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S310 V600R022C10 Configuration Guide - Ethernet Switching

ERPS Configuration

ERPS Configuration

Overview of ERPS

Definition

Ethernet Ring Protection Switching (ERPS) is a protocol defined by the International Telecommunication Union-Telecommunication Standardization Sector (ITU-T) to prevent loops at Layer 2. ERPS is also called G.8032 because its standard number is ITU-T G.8032/Y.1344. It defines the ring automatic protection switching (R-APS) messages and protection switching mechanism.

Purpose

Redundant links (such as those on a ring network) are usually used on an Ethernet switched network to provide link backup and improve network reliability. The use of redundant links, however, may cause loops, leading to broadcast storms and unstable MAC address entries. As a result, the communication quality deteriorates, and communication services may even be interrupted. To prevent loops, the device supports the ring network protocols listed in Table 7-1.
Table 7-1 Ring network protocols supported by the device

Ring Network Protocol

Advantage

Disadvantage

STP/RSTP/MSTP

  • STP, RSTP, and MSTP apply to all Layer 2 networks.

  • STP, RSTP, and MSTP are standard IEEE protocols that allow the device to communicate with devices from other vendors.

STP, RSTP, and MSTP provide slow convergence, which is affected by the network size and cannot meet carrier-class reliability requirements.

ERPS

  • ERPS provides fast convergence, which meets carrier-class reliability requirements.

  • ERPS is a standard ITU-T protocol that allows the device to communicate with devices from other vendors.

  • ERPSv2 supports both single-ring and multi-ring topologies.

The network topology must be planned, and the configuration is complex.

As a standard loop prevention protocol defined by the ITU-T, ERPS overcomes the drawbacks of STP, RSTP, and MSTP. ERPS provides fast convergence, meets carrier-class reliability requirements, and supports multiple networking modes. It has good compatibility and allows the device to communicate with devices from other vendors. Therefore, ERPS is widely used on Layer 2 ring networks.

Understanding ERPS

Basic Concepts of ERPS

ERPS prevents loops at the Ethernet link layer. ERPS works for ERPS rings. It blocks the ring protection link (RPL) owner port and controls other common ports to switch the port status between Forwarding and Discarding to eliminate loops. There are two versions of ERPS: ERPSv1 and ERPSv2. ERPSv2 is fully compatible with ERPSv1 and extends ERPSv1 functions.

In Figure 7-1, DeviceA through DeviceD constitute a ring and are connected to the upstream network. This connection mode will cause a loop on the entire network. To eliminate loops on the network and ensure link connectivity, a loop prevention mechanism needs to be used.

Figure 7-1 ERPS single-ring networking

ERPS can be deployed on the network shown in Figure 7-1. The following describes basic concepts of ERPS based on the figure:

ERPS Ring

An ERPS ring consists of connected Layer 2 switching devices that are configured with the same control VLAN. An ERPS ring is the basic unit of ERPS. An ERPS ring can be a major ring or a sub-ring. By default, an ERPS ring is a major ring. A major ring is a closed ring, whereas a sub-ring is an open ring. Both of them are configured using commands. On the network shown in Figure 7-2, DeviceA through DeviceD constitute a major ring, and DeviceC through DeviceF constitute a sub-ring. Only ERPSv2 supports sub-rings, while ERPSv1 does not.

Figure 7-2 ERPS major ring and sub-ring networking

ERPS Port

ERPS defines three types of ports: RPL owner port, RPL neighbour port, and common port. Only ERPSv2 supports the RPL neighbour port, while ERPSv1 does not.

  • RPL owner port

    An RPL owner port is manually specified. Once specified, it is blocked to prevent loops on the ERPS ring where it resides. An ERPS ring has only one RPL owner port. When the device where the RPL owner port resides receives a message indicating a node or link fault on the ERPS ring, the device unblocks the RPL owner port so that the port resumes sending and receiving traffic, thus ensuring nonstop traffic forwarding. The link where the RPL owner port resides is the RPL.

  • RPL neighbour port

    An RPL neighbour port is directly connected to an RPL owner port. The RPL neighbour port reduces the number of FDB entry updates on the device where the RPL neighbour port resides. Both the RPL owner port and RPL neighbour port are blocked to prevent loops under normal circumstances, and are unblocked if the ERPS ring fails.

  • Common port

    In an ERPS ring, all ports except the RPL owner port and RPL neighbour port are common ports. A common port monitors the status of the directly connected ERPS link and sends messages to notify the other ports of link status changes.

An ERPS port can be in either of the following states:

  • Forwarding: In this state, the port forwards user traffic and sends and receives R-APS PDUs.

  • Discarding: In this state, the port can only send and receive R-APS PDUs.

VLAN

ERPS has two types of VLANs: data VLAN and control VLAN. A data VLAN is used to transmit data packets, and a control VLAN is used to transmit R-APS PDUs. Each ERPS ring must be configured with a control VLAN. After a port is added to an ERPS ring configured with a control VLAN, the port is automatically added to the control VLAN. Different ERPS rings cannot be configured with the same control VLAN.

ERP Instance

On a Layer 2 device running ERPS, the VLANs in which R-APS PDUs and data packets are transmitted must be mapped to an Ethernet Ring Protection (ERP) instance so that ERPS forwards or blocks these packets based on blocking rules. If the VLAN is not mapped to an ERP instance, a broadcast storm may occur on the ring network, causing the ring network to become unavailable.

Timers

ERPS defines four timers: Guard timer, wait to restore (WTR) timer, Holdoff timer, and wait to block (WTB) timer. Only ERPSv2 supports the WTB timer, whereas ERPSv1 does not.

  • Guard timer

    After a faulty link or node recovers or a clear operation is performed, the device sends R-APS No Request (NR) messages to notify other devices of the link or node recovery and starts the Guard timer. Before the Guard timer expires, the device does not process any R-APS NR message to avoid receiving out-of-date R-APS NR messages. If the device still receives an R-APS NR message after the timer expires, the local port enters the Forwarding state.

  • WTR timer

    If a device or link fails, the RPL owner port is unblocked. After the fault is rectified, the faulty port may have not changed from down to up. To prevent network flapping caused by immediate blocking of the RPL owner port, the device starts the WTR timer after the RPL owner port receives an R-APS NR message. If the device receives an R-APS Signal Failed (SF) message before the WTR timer expires, the device disables the WTR timer and does not block the RPL owner port. If the device does not receive any R-APS SF message before the WTR timer expires, the device blocks the RPL owner port when the WTR timer expires and sends an R-APS No Request RPL Blocked (NRRB) message. After receiving the R-APS NRRB message, the other ports set their forwarding status to Forwarding.

  • Holdoff timer

    Layer 2 networks running ERPS may have different requirements on the protection switching sequence. For example, if a server fails on a network that provides multi-layer services, users may require a period of time to restore the server, during which clients are unaware of the fault. That is, protection switching is not performed immediately. You can set a proper Holdoff timer value. If a fault occurs, the fault is not immediately reported to ERPS. Instead, the fault is reported only when the Holdoff timer expires and the fault persists.

  • WTB timer

    When the switching status (Forced Switch or Manual Switch) of a port is cleared, the WTB timer is started. Because multiple ports on an ERPS ring may be manually blocked, the clear operation takes effect only after the WTB timer expires. This prevents the RPL owner port from being blocked immediately.

    The WTB timer cannot be manually specified but depends on the Guard timer configuration. The value of the WTB timer is the value of the Guard timer plus 5s. The default value of the WTB timer is 7s.

Revertive and Non-revertive Switching Modes

After a link fault on an ERPS ring is rectified, re-blocking the RPL owner port depends on the configured revertive or non-revertive switching mode.

  • In revertive switching mode, if the faulty link recovers, the RPL owner port is re-blocked after the WTR timer expires. The blocked link is switched back to the RPL.
  • In non-revertive switching mode, if the faulty link recovers, the WTR timer is not started and the original faulty link is still blocked.

By default, an ERPS ring works in revertive switching mode.

ERPSv1 supports only revertive switching mode, whereas ERPSv2 supports both revertive and non-revertive switching modes.

Port Blocking Modes

Because the RPL on which the RPL owner port resides may have higher bandwidth, you can block a low-bandwidth link so that user traffic can be transmitted on the RPL. ERPS supports Forced Switch (FS) and Manual Switch (MS) modes for blocking a port:
  • FS: A port configured with FS is immediately blocked regardless of whether other links on the ring are faulty.
  • MS: The process of performing an MS operation on a port on an ERPS ring is similar to that of performing an FS operation on a port. The difference is that the MS operation does not take effect if the ERPS ring is not in Idle or Pending state.
In addition to FS and MS operations, ERPS also supports the clear operation. The clear operation applies to the following scenarios:
  • Clears the local MS and FS configurations.
  • Triggers revertive switching before the WTB or WTR timer expires when the ERPS ring is in revertive switching mode.
  • Triggers revertive switching when the ERPS ring is in non-revertive switching mode.

Only ERPSv2 supports port blocking modes, whereas ERPSv1 does not.

R-APS PDU Transmission Mode in a Sub-ring

ERPSv2 supports single-ring and multi-ring topologies. In multi-ring topologies, R-APS PDUs from sub-rings can be transmitted in virtual channel (VC) and non-virtual channel (NVC) modes.

  • VC mode: R-APS PDUs from a sub-ring are transmitted to the major ring through interconnected nodes. That is, interconnected nodes do not terminate R-APS PDUs from a sub-ring. A blocked port on the sub-ring blocks both R-APS PDUs and data traffic on the sub-ring.
  • NVC mode: R-APS PDUs from a sub-ring are terminated on interconnection nodes. A blocked port on the sub-ring blocks data traffic but not R-APS PDUs on the sub-ring.

On the network shown in Figure 7-3, a major ring is interconnected with two sub-rings. The sub-ring on the left transmits R-APS PDUs in VC mode, and the sub-ring on the right transmits R-APS PDUs in NVC mode.

Figure 7-3 Interconnected rings using VC and NVC modes

By default, R-APS PDUs from a sub-ring are transmitted in NVC mode. In a special networking scenario shown in Figure 7-4 where sub-ring links are discontinuous, the VC mode must be used. In other scenarios, the default NVC mode is recommended. On the network shown in Figure 7-4, links b and d belong to major rings 1 and 2 respectively, and links a and c belong to a sub-ring. Links a and c are independent of each other and cannot detect the status change of each other. Therefore, VCs must be used to transmit R-APS PDUs.

Figure 7-4 Network diagram of a special scenario where virtual channels are used
Table 7-2 lists the advantages and disadvantages of R-APS PDU transmission modes on sub-rings using VC and NVC modes.
Table 7-2 Comparison between VC and NVC modes

R-APS PDU Transmission Mode in a Sub-ring

Advantage

Disadvantage

VC

This mode can be applied to the special networking scenario shown in Figure 7-4.

R-APS virtual channels on a sub-ring are affected by the topology of adjacent rings. Resources need to be reserved and control VLAN IDs need to be allocated for R-APS virtual channels on the network where these virtual channels reside.

NVC

This mode does not require resource reservation and control VLAN ID assignment from adjacent rings.

This mode cannot be applied to the special networking scenario shown in Figure 7-4.

ERPSv1 and ERPSv2

ERPS has two versions: ERPSv1 and ERPSv2. ERPSv1 was released by the ITU-T in June 2008, and ERPSv2 was released by the ITU-T in August 2010. ERPSv2 is fully compatible with ERPSv1 and extends ERPSv1 functions. Table 7-3 lists the differences between ERPSv1 and ERPSv2.
Table 7-3 Comparison between ERPSv1 and ERPSv2

Function

ERPSv1

ERPSv2

Ring creation

Only a single ring can be created. Sub-rings cannot be configured.

Multiple rings can be created, that is, major rings and sub-rings can be configured.

Port role configuration

The RPL owner port and common ports can be configured.

The RPL owner port, the RPL neighbour port, and common ports can be configured.

Topology change notification

This function is not supported.

This function is supported.

Transmitting R-APS PDUs from sub-rings in VC and NVC modes

This function is not supported.

This function is supported.

Revertive and non-revertive switching mode

The revertive switching mode is used by default and cannot be configured. The non-revertive switching mode is not supported.

Both the revertive switching and non-revertive switching modes can be configured.

Manually switching blocked ports

This function is not supported.

This function is supported. Both FS and MS modes are supported.

ERPSv2 is fully compatible with ERPSv1. If all devices on an ERPS ring support both ERPSv1 and ERPSv2, configuring ERPSv2 is recommended.

R-APS PDUs

ERPS protocol packets are called ring automatic protection switching (R-APS) protocol data units (PDUs). R-APS PDUs contain ERPS ring information and are transmitted on ERPS rings to exchange port information between devices. Figure 7-5 shows the basic R-APS PDU format.

Figure 7-5 Basic R-APS PDU format

Table 7-4 describes the fields in an R-APS PDU.

Table 7-4 Fields in an R-APS PDU

Field

Length

Description

MEL

3 bits

Indicates the maintenance entity group (MEG) level.

Version

5 bits
  • 0x00: ERPSv1
  • 0x01: ERPSv2

OpCode

8 bits

Indicates that the PDU is an R-APS PDU. This field has a fixed value of 0x28.

Flags

8 bits

This field has a fixed value of 0x00. It is ignored during packet receiving.

Type-length-value (TLV) Offset

8 bits

Indicates that the TLV starts after an offset of 32 bytes. This field has a fixed value of 0x20.

R-APS Specific Information

32 x 8 bits

Carries ERPS ring information. This field is the core field in an R-APS PDU. ERPSv1 and ERPSv2 differ in some sub-fields of this field. Figure 7-6 shows the sub-fields contained in this field in ERPSv1, and Figure 7-7 shows the sub-fields contained in this field in ERPSv2.

TLV

Unlimited

Describes information to be loaded. The End TLV has a fixed value of 0x00.
Figure 7-6 Format of the R-APS Specific Information field in ERPSv1

Figure 7-7 Format of the R-APS Specific Information field in ERPSv2

Table 7-5 describes the meanings of sub-fields in the R-APS Specific Information field.
Table 7-5 Meanings of sub-fields in the R-APS Specific Information field

Field

Length

Description

Request/State

4 bits

Indicates that this R-APS PDU is a request or state PDU. The value can be:

  • 1101: Forced Switch (FS)

  • 1110: Event

  • 1011: Signal Failed (SF)

  • 0111: Manual Switch (MS)

  • 0000: No Request (NR)

  • Others: reserved

Reserved 1

4 bits

In ERPSv1, this field is Reserved 1, indicating that it is reserved for subsequent packet response or protection type identification.

In ERPSv2, this field is Sub-code.
  • If the value of the Request/State field is 1110, the value of this field is 0000, indicating an FDB entry update request.
  • If the Request/State field is set to other values, the value of this field is all 0s. This field is reserved and will be ignored during R-APS PDU receiving.

Sub-code

Status

8 bits
Includes the following status information:

  • RPL Blocked (RB) (1 bit): If the value is 1, the RPL is blocked. If the value is 0, the RPL is unblocked. The nodes where the RPL owner port does not reside set this field to 0 when sending a PDU.

  • Do Not Flush (DNF) (1 bit): If the value is 1, an FDB flush is not triggered when an R-APS PDU is received. If the value is 0, an FDB flush is triggered when an R-APS PDU is received.

  • Blocked port reference (BPR) (1 bit): If the value is 0, the first port is blocked. If the value is 1, the second port is blocked.

    Only ERPSv2 supports this field.

  • Status Reserved: This field is reserved. This field is set to all 0s during R-APS PDU sending and is ignored during R-APS PDU receiving. In ERPSv1, this field has 6 bits. In ERPSv2, this field has 5 bits.

Node ID

6 x 8 bits

Indicates the MAC address of a node on an ERPS ring. This field is informational and does not affect protection switching on the ERPS ring.

Reserved 2

24 x 8 bits

Reserved field. This field is set to all 0s during R-APS PDU sending and is ignored during R-APS PDU receiving.

ERPS Single-Ring

ERPS is a standard ring network protocol used to prevent loops on an ERPS ring at the Ethernet link layer. To prevent loops on an ERPS ring, you can enable the loop prevention mechanism to block the RPL owner port to eliminate loops. If a link on the ring network fails, the device running ERPS immediately unblocks the blocked port and performs link protection switching to restore communication between nodes on the ring network. In an ERPS single-ring scenario, only one ERPS ring is configured on an ERPS network. Both ERPSv1 and ERPSv2 support ERPS single-ring.

This section describes how ERPS is implemented on a single-ring network when links are normal, when a link fails, and when the link recovers (including protection switching operations).

Normal Links

In Figure 7-8, DeviceA through DeviceE constitute a ring and can communicate with each other.
  1. To prevent loops, ERPS blocks the RPL owner port and also the RPL neighbour port (if any). Other ports can forward service traffic.
  2. The RPL owner port on the ERPS ring sends R-APS NRRB messages to other nodes on the ring at an interval of 5s, indicating that ERPS links are normal.
Figure 7-8 ERPS single-ring networking (normal links)

Link Fault

In Figure 7-9, if the link between DeviceD and DeviceE fails, the ERPS protection switching mechanism is triggered. The ports on both ends of the faulty link are blocked, and the RPL owner port and RPL neighbour port are unblocked to send and receive user traffic, ensuring uninterrupted traffic forwarding. The detailed process is as follows:

  1. After DeviceD and DeviceE detect the link fault, they block their ports on the faulty link and update their FDB entries.
  2. DeviceD and DeviceE send three consecutive R-APS SF messages carrying local link fault information to the other devices and then send R-APS SF messages at an interval of 5s.
  3. After receiving R-APS SF messages, the other devices update their FDB entries. After receiving R-APS SF messages, DeviceC (where the RPL owner port resides) unblocks the RPL owner port and updates its FDB entries. Similarly, after receiving R-APS SF messages, DeviceB (where the RPL neighbour port resides) unblocks the RPL neighbour port and updates its FDB entries.
Figure 7-9 ERPS single-ring networking (link fault)

Link Recovery

After the faulty link recovers, if the ERPS ring uses the revertive switching mode, the device where the RPL owner port resides blocks the RPL again, and the link that has recovered is used to forward traffic. If the ERPS ring uses the non-revertive switching mode, the link that has recovered is still blocked, and the RPL is not blocked. The following uses the revertive switching mode as an example to describe the recovery process:

  1. After the link between DeviceD and DeviceE recovers, DeviceD and DeviceE start the Guard timer to prevent them from receiving out-of-date R-APS NR messages. They do not receive any R-APS NR messages before the Guard timer expires. At the same time, DeviceD and DeviceE send R-APS NR messages.
  2. After receiving R-APS NR messages, DeviceC on which the RPL owner port resides starts the WTR timer. After the WTR timer expires, DeviceC blocks the RPL owner port and sends R-APS NRRB messages.
  3. After receiving R-APS NRRB messages from DeviceC, DeviceD and DeviceE unblock their blocked ports, stop sending R-APS NR messages, and update their FDB entries. After receiving R-APS NRRB messages from DeviceC, the other devices update their FDB entries.

ERPS Multi-Ring

In an ERPS multi-ring scenario, multiple ERPS rings are configured on an ERPS network. ERPSv1 supports only single-ring topologies, whereas ERPSv2 supports both single-ring and multi-ring topologies. An ERPS multi-ring network consists of one or more major rings and sub-rings. R-APS PDUs from sub-rings can be transmitted in VC or NVC mode, depending on whether the R-APS PDUs enter the major ring.

This section describes how ERPS is implemented on a multi-ring network where R-APS PDUs from sub-rings are transmitted in NVC mode when links are normal, when a link fails, and when the link recovers.

Normal Links

In Figure 7-10, DeviceA through DeviceE constitute a major ring. DeviceB, DeviceC, and DeviceF constitute sub-ring 1, and DeviceC, DeviceD, and DeviceG constitute sub-ring 2. The devices on each ring can communicate with each other.

  1. To prevent loops, each ring blocks its RPL owner port.
  2. The RPL owner port on the major ring sends R-APS NRRB messages to other nodes on the major ring at an interval of 5s. Similarly, the RPL owner ports on sub-rings 1 and 2 send R-APS NR messages to other nodes on their respective rings at an interval of 5s. The R-APS PDUs of the major ring are transmitted only on the major ring. The R-APS PDUs of the two sub-rings are terminated on the interconnected nodes and are not transmitted to the major ring.

Traffic exchanged between PC1 and the upstream network is transmitted along the path PC1 <-> DeviceF <-> DeviceB <-> DeviceA <-> Router1, and traffic exchanged between PC2 and the upstream network is transmitted along the path PC2 <-> DeviceG <-> DeviceD <-> DeviceE <-> Router2.

Figure 7-10 ERPS multi-ring networking (normal links)

Link Fault

In Figure 7-11, if the link between DeviceD and DeviceG fails, the ERPS protection switching mechanism is triggered. The ports on both ends of the faulty link are blocked, and the RPL owner port on sub-ring 2 is unblocked to send and receive traffic. User traffic of PC1 is not affected. To ensure that downlink traffic of PC2 is not interrupted, interconnected nodes DeviceC and DeviceD need to notify the other nodes on the major ring of the topology change on sub-ring 2. Traffic exchanged between PC2 and the upstream network is transmitted along the path PC2 <-> DeviceG <-> DeviceC <-> DeviceB <-> DeviceA <-> DeviceE <-> Router2. The detailed process is as follows:

  1. After DeviceD and DeviceG detect the link fault, they block their ports on the faulty link and update their FDB entries.
  2. DeviceG sends three consecutive R-APS SF messages carrying local link fault information within sub-ring 2 immediately after detecting the link fault and then sends R-APS SF messages at an interval of 5s.
  3. DeviceG where the RPL owner port resides unblocks the RPL owner port and updates its FDB entries.
  4. After the interconnected node DeviceC receives R-APS SF messages, it updates its FDB entries. After detecting the topology change, DeviceC and DeviceD send R-APS Event messages within the major ring to notify the other nodes of the topology change on sub-ring 2.
  5. After receiving R-APS Event messages, the other nodes on the major ring update their FDB entries.
Figure 7-11 ERPS multi-ring networking (link fault)

Link Recovery

After the faulty link recovers, if the ERPS rings use the revertive switching mode, the device where the RPL owner port resides blocks the RPL again, and the link that has recovered is used to forward traffic. If the ERPS rings use the non-revertive switching mode, the link that has recovered is still blocked, and the RPL is not blocked. The following uses the revertive switching mode as an example to describe the recovery process:

  1. After the link between DeviceD and DeviceG recovers, DeviceD and DeviceG start the Guard timer to avoid receiving out-of-date R-APS PDUs. They do not receive any R-APS PDUs before the timer expires. At the same time, DeviceD and DeviceG send R-APS NR messages within sub-ring 2.
  2. DeviceG where the RPL owner port resides starts the WTR timer. After the WTR timer expires, DeviceG blocks the RPL owner port and unblocks its port on the link that has recovered. At the same time, DeviceG sends R-APS NRRB messages.
  3. After receiving R-APS NRRB messages from DeviceG, DeviceD unblocks its blocked port, stops sending R-APS NR messages, and updates its FDB entries. After receiving R-APS NRRB messages from DeviceG, DeviceC also updates its FDB entries.
  4. After DeviceC and DeviceD update their FDB entries, they send R-APS Event messages within the major ring to notify the other nodes of the topology change on sub-ring 2.
  5. After receiving R-APS Event messages, the other nodes on the major ring update their FDB entries.

Finally, the user traffic of PC2 is switched back to the path shown in Figure 7-10.

Configuration Precautions for ERPS

Hardware Requirements

Table 7-6 Hardware requirements

Series

Models

S310 series

S310-24P4S/S310-24T4S/S310-48T4S

Feature Requirements

Table 7-7 Feature requirements

Feature Requirements

Series

Models

ERPS can be associated only with outward-facing MEPs.

The association does not take effect in other scenarios.

You are advised to ensure that the associated MEP is outward-facing.

S310 series

S310-24P4S/S310-24T4S/S310-48T4S

Default Settings for ERPS

Table 7-8 Default settings for ERPS

Parameter

Default Setting

ERPS ring

Not created

Guard timer

200 milliseconds

WTR timer

5 minutes

Holdoff timer

0 deciseconds

ERPS version

ERPSv1

Configuring ERPSv1

Creating an ERPS Ring

Context

ERPS works for ERPS rings. An ERPS ring consists of connected Layer 2 switching devices that are configured with the same control VLAN and data VLAN. Before configuring other ERPS functions, create an ERPS ring.

Procedure

  1. Enter the system view.

    system-view

  2. Create an ERPS ring and enter the ERPS ring view.

    erps ring ring-id

  3. (Optional) Enable the function of encapsulating an ERPS ring ID into the destination MAC address of R-APS PDUs.

    encapsulate-ring-id enable

    By default, the function of encapsulating an ERPS ring ID into the destination MAC address of R-APS PDUs is disabled.

  4. (Optional) Configure a description.

    description description

    By default, the description of an ERPS ring is the ERPS ring name, for example, Ring 1.

Configuring a Control VLAN

Context

Control and data VLANs have different functions. On an ERPS ring, a control VLAN is used to transmit only R-APS PDUs but not user service packets, which improves ERPS security. All the devices on an ERPS ring must be configured with the same control VLAN. Different ERPS rings cannot use the same control VLAN.

Procedure

  1. Enter the system view.

    system-view

  2. Enter the view of a created ERPS ring.

    erps ring ring-id

  3. Configure a control VLAN for the ERPS ring.

    control-vlan vlan-id

    • If you run the control-vlan command multiple times, only the latest configuration takes effect.
    • The control VLAN specified by the vlan-id parameter must be a VLAN that has not been created or used.
    • If ports have been added to the ERPS ring, the control VLAN cannot be changed. To delete a configured control VLAN, you must run the undo erps ring command in the interface view or the undo port command in the ERPS ring view to remove the ports from the ERPS ring, and then run the undo control-vlan command to delete the control VLAN.
    • After a control VLAN is created, the vlan batch vlan-id1 [ to vlan-id2 ] &<1-10> command is automatically displayed in the configuration file.
    • After a port is added to an ERPS ring configured with a control VLAN, the port is automatically added to the control VLAN. If the port is a trunk port, the port trunk allow-pass vlan vlan-id command is automatically displayed in the view of the port in the configuration file. If the port is a hybrid port, the port hybrid tagged vlan vlan-id command is automatically displayed in the view of the port in the configuration file.

Configuring an ERP Instance and Activating the Mapping Between the ERP Instance and a VLAN

Context

On a Layer 2 device running ERPS, the VLANs in which R-APS PDUs and data packets are transmitted must be mapped to an ERP instance so that ERPS forwards or blocks the packets based on blocking rules. Otherwise, the preceding packets may cause broadcast storms on the ring network, causing the network to become unavailable.

Procedure

  1. Enter the system view.

    system-view

  2. Enter the ERPS ring view.

    erps ring ring-id

  3. Create an ERP instance for the ERPS ring.

    protected-instance { all | { instance-id1 [ to instance-id2 ] } &<1-10> }

    By default, no ERP instance is configured for an ERPS ring.

    • If the stp mode command has been run in the system view to set the STP working mode to VBST, the ERP instance configured using the protected-instance command must be a created static instance.

    • If you run the protected-instance command multiple times in the same ERPS ring, multiple ERP instances are configured.

    • If ports have been added to the ERPS ring, the ERP instance cannot be changed. To delete a configured ERP instance, you must run the undo erps ring command in the interface view or the undo port command in the ERPS ring view to remove the ports from the ERPS ring, and then run the undo protected-instance command to delete the ERP instance.

  4. Exit the ERPS ring view to enter the system view.

    quit

  5. Configure the mapping between the ERP instance and a VLAN.
    1. Enter the MST region view.

      stp region-configuration

    2. Configure the mapping between the ERP instance and a VLAN.

      instance instance-id vlan { vlan-id1 [ to vlan-id2 ] } &<1-10>

      By default, all VLANs in an MST region are mapped to instance 0.

      The value of the instance-id parameter must be the same as the value of the instance-id parameter specified in the protected-instance command.

      • A VLAN cannot be mapped to multiple instances. If you map a VLAN that has been mapped to an instance to another instance, the original mapping is deleted.

      • The vlan-mapping modulo modulo command configures mappings between MSTIs and VLANs based on a default algorithm. However, the mappings configured using this command cannot meet the actual requirements. Therefore, this command is not recommended.

      • To configure the mapping between an ERP instance and a MUX VLAN, you are advised to configure the principal VLAN, group VLANs, and separate VLANs of the MUX VLAN to map the same ERP instance. Otherwise, loops may occur.

Adding a Layer 2 Port to an ERPS Ring and Configuring the Port Role

Prerequisites

Before adding a Layer 2 port to an ERPS ring and configuring the port role, you have completed the following tasks:

  • Disable STP and Smart Link on the Layer 2 port to be added to the ERPS ring.
    • If STP has been enabled on the port, run the stp disable command in the interface view to disable STP.
    • If Smart Link has been enabled on the port, run the undo port command in the Smart Link group view to disable Smart Link.

  • Run the control-vlan command to configure a control VLAN and the protected-instance command to configure an ERP instance.

Context

After an ERPS ring is created, add Layer 2 ports to the ERPS ring and configure the port roles so that ERPS can work properly.

Use either of the following methods to add a Layer 2 port to an ERPS ring and configure the port role:

  • In the ERPS ring view, add a specified port to the ERPS ring and configure the port role.

  • In the interface view, add the port to an ERPS ring and configure the port role.

  • An ERPS-enabled port must be configured as a trunk or hybrid port because it needs to allow packets from both the control VLAN and data VLAN to pass through.

  • Currently, packets for updating MAC addresses cannot be sent separately. Therefore, it is not recommended that a direct link between two upstream nodes be configured as the RPL.

  • Before changing the port role, run the shutdown command to shut down the port. After the port role is changed, run the undo shutdown command to enable the port. Otherwise, traffic cannot be forwarded.

  • Before adding a port to an ERPS ring, disable port security on the port. Otherwise, loops cannot be prevented.

Procedure

  1. Enter the system view.

    system-view

  2. Add a Layer 2 port to an ERPS ring.

    • In the ERPS ring view, add a specified port to the ERPS ring and configure the port role.
      interface interface-type interface-number
stp disable
port link-type trunk
port trunk allow-pass vlan { { vlan-id1 [ to vlan-id2 ] }&<1-10> | all }
quit
erps ring ring-id
port interface-type interface-number [ rpl owner ]
    • In the interface view, add the port to an ERPS ring and configure the port role.
      interface interface-type interface-number
stp disable
port link-type trunk
port trunk allow-pass vlan { { vlan-id1 [ to vlan-id2 ] }&<1-10> | all }
erps ring ring-id [ rpl owner ]

(Optional) Configuring the Self-Healing Function for an ERPS Ring

Context

On a stable ERPS ring, if a node where the RPL owner port does not reside incorrectly sends R-APS SF messages when no fault occurs, the RPL owner port may be unblocked, causing a loop. After the self-healing function is enabled, the device eliminates the loop caused by incorrectly sent messages through status detection.

Procedure

  1. Enter the system view.

    system-view

  2. Enter the view of a created ERPS ring.

    erps ring ring-id

  3. Disable the self-healing function for the ERPS ring.

    erps self-heal disable

    By default, this function is enabled.

Verifying the ERPSv1 Configuration

Procedure

  1. Run the display erps [ ring ring-id ] [ verbose ] command to check device ports added to an ERPS ring and ERPS ring configurations.
  2. Run the display erps interface interface-type interface-number [ ring ring-id ] command to check the physical status of ports added to an ERPS ring.

Example for Configuring ERPSv1

Networking Requirements

Redundant links are usually used on an Ethernet switched network to provide link backup and improve network reliability. The use of redundant links, however, may cause loops on the switched network, leading to broadcast storms and unstable MAC address entries. As a result, the communication quality deteriorates, and communication services may even be interrupted. ERPS can be configured on devices on a ring network to prevent loops caused by redundant links. As a Layer 2 loop prevention protocol defined by the ITU-T, ERPS provides fast convergence that can meet carrier-class reliability requirements.

In Figure 7-12, DeviceA, DeviceB, DeviceC, and DeviceD constitute an ERPS ring.

Figure 7-12 ERPS single-ring networking

In this example, interface 1 and interface 2 represent GE1/0/1 and GE1/0/2, respectively.


Configuration Roadmap

The configuration roadmap is as follows:

  1. Set the link type of all ports to be added to an ERPS ring to trunk.

  2. Create an ERPS ring and configure a control VLAN and an ERP instance.

  3. Add Layer 2 ports to the ERPS ring and configure port roles.

  4. Configure the Guard timer and WTR timer for the ERPS ring.

  5. Configure the Layer 2 forwarding function on DeviceA through DeviceD.

Procedure

  1. Set the link type of all ports to be added to an ERPS ring to trunk.

    # Configure DeviceA. The configurations of DeviceB, DeviceC, and DeviceD are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    <HUAWEI> system-view
[HUAWEI] sysname DeviceA
[DeviceA] interface ge 1/0/1
[DeviceA-GE1/0/1] port link-type trunk
[DeviceA-GE1/0/1] quit
[DeviceA] interface ge 1/0/2
[DeviceA-GE1/0/2] port link-type trunk
[DeviceA-GE1/0/2] quit

  2. Create ERPS ring 1 and configure an ERP instance. Set the control VLAN ID of the ERPS ring to 10 and configure ERPS ring 1 to transmit data packets from VLANs 100 to 200.

    # Configure DeviceA. The configurations of DeviceB, DeviceC, and DeviceD are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    [DeviceA] stp region-configuration
[DeviceA-mst-region] instance 1 vlan 10 100 to 200
[DeviceA-mst-region] quit
[DeviceA] erps ring 1
[DeviceA-erps-ring1] control-vlan 10
[DeviceA-erps-ring1] protected-instance 1
[DeviceA-erps-ring1] quit

  3. Add Layer 2 ports to the ERPS ring and configure port roles. Configure GE1/0/1 on DeviceB as the RPL owner port.

    # Configure DeviceA. The configurations of DeviceC and DeviceD are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    [DeviceA] interface ge 1/0/1
[DeviceA-GE1/0/1] stp disable
[DeviceA-GE1/0/1] erps ring 1
[DeviceA-GE1/0/1] quit
[DeviceA] interface ge 1/0/2
[DeviceA-GE1/0/2] stp disable
[DeviceA-GE1/0/2] erps ring 1
[DeviceA-GE1/0/2] quit

    # Configure DeviceB.

    [DeviceB] interface ge 1/0/1
[DeviceB-GE1/0/1] stp disable
[DeviceB-GE1/0/1] erps ring 1 rpl owner
[DeviceB-GE1/0/1] quit
[DeviceB] interface ge 1/0/2
[DeviceB-GE1/0/2] stp disable
[DeviceB-GE1/0/2] erps ring 1
[DeviceB-GE1/0/2] quit

  4. Configure the Guard timer and WTR timer for the ERPS ring.

    # Configure DeviceA. The configurations of DeviceB, DeviceC, and DeviceD are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    [DeviceA] erps ring 1
[DeviceA-erps-ring1] wtr-timer 6
[DeviceA-erps-ring1] guard-timer 100
[DeviceA-erps-ring1] quit

  5. Configure the Layer 2 forwarding function on DeviceA through DeviceD.

    # Configure DeviceA. The configurations of DeviceB, DeviceC, and DeviceD are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    [DeviceA] vlan batch 100 to 200
[DeviceA] interface ge 1/0/1
[DeviceA-GE1/0/1] undo port trunk allow-pass vlan 1
[DeviceA-GE1/0/1] port trunk allow-pass vlan 100 to 200
[DeviceA-GE1/0/1] quit
[DeviceA] interface ge 1/0/2
[DeviceA-GE1/0/2] undo port trunk allow-pass vlan 1
[DeviceA-GE1/0/2] port trunk allow-pass vlan 100 to 200 
[DeviceA-GE1/0/2] quit

  6. Verify the configuration.

    # After the network becomes stable, run the display erps command to check brief information about the ERPS ring and ports added to the ERPS ring. The following example uses the command output on DeviceB.

    [DeviceB] display erps
D  : Discarding
F  : Forwarding
R  : RPL Owner
N  : RPL Neighbour
FS : Forced 
MS : Manual Switch
Total number of rings configured = 1
Ring  Control  WTR Timer  Guard Timer  Port 1               Port 2
ID    VLAN     (min)      (csec)
--------------------------------------------------------------------------------
   1       10          6          100  (D,R)GE1/0/1         (F)GE1/0/2
--------------------------------------------------------------------------------

    # Run the display erps verbose command to check detailed information about the ERPS ring and ports added to the ERPS ring. The following example uses the command output on DeviceB.

    [DeviceB] display erps verbose
Ring ID                             : 1
Description                         : Ring 1
Control Vlan                        : 10
Protected Instance                  : 1 
Service Vlan                        : 100 to 200
WTR Timer Setting (min)             : 6      Running (s)           : 0  
Guard Timer Setting (csec)          : 100    Running (csec)        : 0  
Holdoff Timer Setting (deciseconds) : 0      Running (deciseconds) : 0  
WTB Timer Running (csec)            : 0  
Ring State                          : Idle
RAPS_MEL                            : 7
Revertive Mode                      : Revertive
R-APS Channel Mode                  : -
Version                             : 1
Sub-ring                            : No 
Forced Switch Port                  : -
Manual Switch Port                  : -
TC-Notify                           : -
Time since last topology change     : 0 days 4h:12m:20s
--------------------------------------------------------------------------------
Port                Port Role     Port Status     Signal Status
--------------------------------------------------------------------------------
GE1/0/1             RPL Owner     Discarding      Non-failed      
GE1/0/2             Common        Forwarding      Non-failed

Configuration Scripts

  • DeviceA

    #
sysname DeviceA
#
vlan batch 100 to 200
#
stp region-configuration
 instance 1 vlan 10 100 to 200
#
erps ring 1
 control-vlan 10
 protected-instance 1
 wtr-timer 6
 guard-timer 100
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200 
 stp disable
 erps ring 1
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200 
 stp disable
 erps ring 1
#
return

  • DeviceB

    #
sysname DeviceB
#
vlan batch 100 to 200
#
stp region-configuration
 instance 1 vlan 10 100 to 200
#
erps ring 1
 control-vlan 10
 protected-instance 1
 wtr-timer 6
 guard-timer 100
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200 
 stp disable
 erps ring 1
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200 
 stp disable
 erps ring 1 rpl owner
#
return

  • DeviceC

    #
sysname DeviceC
#
vlan batch 100 to 200
#
stp region-configuration
 instance 1 vlan 10 100 to 200
#
erps ring 1
 control-vlan 10
 protected-instance 1
 wtr-timer 6
 guard-timer 100
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200 
 stp disable
 erps ring 1
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200 
 stp disable
 erps ring 1
#
return

  • DeviceD

    #
sysname DeviceD
#
vlan batch 100 to 200
#
stp region-configuration
 instance 1 vlan 10 100 to 200
#
erps ring 1
 control-vlan 10
 protected-instance 1
 wtr-timer 6
 guard-timer 100
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200 
 stp disable
 erps ring 1
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200 
 stp disable
 erps ring 1
#
return

Configuring ERPSv2

Creating an ERPS Ring

Context

ERPS works for ERPS rings. An ERPS ring consists of connected Layer 2 switching devices that are configured with the same control VLAN and data VLAN. Before configuring other ERPS functions, create an ERPS ring.

Procedure

  1. Enter the system view.

    system-view

  2. Create an ERPS ring and enter the ERPS ring view.

    erps ring ring-id

    By default, an ERPS ring created using the erps ring ring-id command is a major ring.

  3. Configure the device to run ERPSv2.

    version v2

    By default, the device runs ERPSv1.

    Before changing ERPSv2 to ERPSv1, delete ERPS configurations that are not supported in ERPSv1.

  4. (Optional) Configure the ERPS ring as a sub-ring.

    sub-ring

    By default, an ERPS ring is a major ring. The difference between a major ring and a sub-ring is that the major ring is a closed ring but the sub-ring is not. If the ERPS ring needs to be configured as a major ring, skip this step.

    Ensure that no port is added to the ERPS ring to be configured as a sub-ring. If a port is added to the ERPS ring, you must run the undo erps ring command in the interface view or the undo port command in the ERPS ring view to remove the port from the ERPS ring.

  5. (Optional) Configure the R-APS PDU transmission mode in a sub-ring.

    virtual-channel { enable | disable }

    By default, nodes in a sub-ring transmit R-APS PDUs in NVC mode. The default transmission mode is recommended. When the sub-ring links are discontinuous, the VC transmission mode is required. If the ERPS ring is a major ring, skip this step.

    To use a virtual channel, configure the VC transmission mode on all nodes of the sub-ring and the interconnected nodes of the sub-ring and major ring.

  6. (Optional) Enable the function of encapsulating an ERPS ring ID into the destination MAC address of R-APS PDUs.

    encapsulate-ring-id enable

    By default, the function of encapsulating an ERPS ring ID into the destination MAC address of R-APS PDUs is disabled.

  7. (Optional) Configure a description.

    description description

    By default, the description of an ERPS ring is the ERPS ring name, for example, Ring 1.

Configuring a Control VLAN

Context

Control and data VLANs have different functions. On an ERPS ring, a control VLAN is used to transmit only R-APS PDUs but not user service packets, which improves ERPS security. All the devices on an ERPS ring must be configured with the same control VLAN. Different ERPS rings cannot use the same control VLAN.

Procedure

  1. Enter the system view.

    system-view

  2. Enter the view of a created ERPS ring.

    erps ring ring-id

  3. Configure a control VLAN for the ERPS ring.

    control-vlan vlan-id

    • If you run the control-vlan command multiple times, only the latest configuration takes effect.
    • The control VLAN specified by the vlan-id parameter must be a VLAN that has not been created or used.
    • If ports have been added to the ERPS ring, the control VLAN cannot be changed. To delete a configured control VLAN, you must run the undo erps ring command in the interface view or the undo port command in the ERPS ring view to remove the ports from the ERPS ring, and then run the undo control-vlan command to delete the control VLAN.
    • After a control VLAN is created, the vlan batch vlan-id1 [ to vlan-id2 ] &<1-10> command is automatically displayed in the configuration file.
    • After a port is added to an ERPS ring configured with a control VLAN, the port is automatically added to the control VLAN. If the port is a trunk port, the port trunk allow-pass vlan vlan-id command is automatically displayed in the view of the port in the configuration file. If the port is a hybrid port, the port hybrid tagged vlan vlan-id command is automatically displayed in the view of the port in the configuration file.

Configuring an ERP Instance and Activating the Mapping Between the ERP Instance and a VLAN

Context

On a Layer 2 device running ERPS, the VLANs in which R-APS PDUs and data packets are transmitted must be mapped to an ERP instance so that ERPS forwards or blocks the packets based on blocking rules. Otherwise, the preceding packets may cause broadcast storms on the ring network, causing the network to become unavailable.

Procedure

  1. Enter the system view.

    system-view

  2. Enter the ERPS ring view.

    erps ring ring-id

  3. Create an ERP instance for the ERPS ring.

    protected-instance { all | { instance-id1 [ to instance-id2 ] } &<1-10> }

    By default, no ERP instance is configured for an ERPS ring.

    • If the stp mode command has been run in the system view to set the STP working mode to VBST, the ERP instance configured using the protected-instance command must be a created static instance.

    • If you run the protected-instance command multiple times in the same ERPS ring, multiple ERP instances are configured.

    • If ports have been added to the ERPS ring, the ERP instance cannot be changed. To delete a configured ERP instance, you must run the undo erps ring command in the interface view or the undo port command in the ERPS ring view to remove the ports from the ERPS ring, and then run the undo protected-instance command to delete the ERP instance.

  4. Exit the ERPS ring view to enter the system view.

    quit

  5. Configure the mapping between the ERP instance and a VLAN.
    1. Enter the MST region view.

      stp region-configuration

    2. Configure the mapping between the ERP instance and a VLAN.

      instance instance-id vlan { vlan-id1 [ to vlan-id2 ] } &<1-10>

      By default, all VLANs in an MST region are mapped to instance 0.

      The value of the instance-id parameter must be the same as the value of the instance-id parameter specified in the protected-instance command.

      • A VLAN cannot be mapped to multiple instances. If you map a VLAN that has been mapped to an instance to another instance, the original mapping is deleted.

      • The vlan-mapping modulo modulo command configures mappings between MSTIs and VLANs based on a default algorithm. However, the mappings configured using this command cannot meet the actual requirements. Therefore, this command is not recommended.

      • To configure the mapping between an ERP instance and a MUX VLAN, you are advised to configure the principal VLAN, group VLANs, and separate VLANs of the MUX VLAN to map the same ERP instance. Otherwise, loops may occur.

Adding a Layer 2 Port to an ERPS Ring and Configuring the Port Role

Prerequisites

  • Disable STP and Smart Link on the Layer 2 port to be added to an ERPS ring.
    • If STP has been enabled on the port, run the stp disable command in the interface view to disable STP.
    • If Smart Link has been enabled on the port, run the undo port command in the Smart Link group view to disable Smart Link.

  • Before adding a port to an ERPS ring, run the control-vlan command to configure a control VLAN and the protected-instance command to configure an ERP instance.

Context

After an ERPS ring is created, add Layer 2 ports to the ERPS ring and configure the port roles so that ERPS can work properly.

Use either of the following methods to add a Layer 2 port to an ERPS ring:

  • In the ERPS ring view, add a specified port to the ERPS ring and configure the port role.

  • In the interface view, add the port to an ERPS ring and configure the port role.

  • An ERPS-enabled port must be configured as a trunk or hybrid port because it needs to allow packets from both the control VLAN and data VLAN to pass through.

  • Currently, packets for updating MAC addresses cannot be sent separately. Therefore, it is not recommended that a direct link between two upstream nodes be configured as the RPL.

  • Before changing the port role, run the shutdown command to shut down the port. After the port role is changed, run the undo shutdown command to enable the port. Otherwise, traffic cannot be forwarded.

  • Before adding a port to an ERPS ring, disable port security on the port. Otherwise, loops cannot be prevented.

Procedure

  1. Enter the system view.

    system-view

  2. Add a Layer 2 port to an ERPS ring.

    • In the ERPS ring view, add a specified port to the ERPS ring and configure the port role.
      interface interface-type interface-number
stp disable
port link-type trunk
port trunk allow-pass vlan { { vlan-id1 [ to vlan-id2 ] }&<1-10> | all }
quit
erps ring ring-id
port interface-type interface-number [ rpl { owner | neighbour } ]
    • In the interface view, add the port to an ERPS ring and configure the port role.
      interface interface-type interface-number
stp disable
port link-type trunk
port trunk allow-pass vlan { { vlan-id1 [ to vlan-id2 ] }&<1-10> | all }
erps ring ring-id [ rpl { owner | neighbour } ]

Configuring the Topology Change Notification Function

Context

If an upper-layer Layer 2 network is not notified of the topology change in an ERPS ring, MAC address entries on the upper-layer Layer 2 network are not updated. As a result, user traffic is interrupted. To ensure nonstop traffic transmission, configure the topology change notification function and specify the ERPS rings that will be notified of the topology change.

Frequent topology change notifications degrade the CPU processing capability of devices in an ERPS ring and cause the devices to frequently update Flush-FDB messages, consuming bandwidth resources. To prevent this problem, suppress topology change notification messages. You can set the topology change protection interval to suppress topology change notification messages and set the maximum number of topology change notification messages that can be processed during the topology change protection interval to prevent frequent MAC address and ARP entry deletion.

Procedure

  1. Enter the system view.

    system-view

  2. Enter the view of a created ERPS ring.

    erps ring ring-id

  3. Configure the ERPS ring to notify other ERPS rings of its topology change.

    tc-notify erps ring { ring-id1 [ to ring-id2 ] } &<1-10>

    The ring-id1 [ to ring-id2 ] parameter specifies the start and end IDs of the ERPS rings that will be notified of the topology change. Ensure that the rings specified by ring-id1 and ring-id2 exist. Otherwise, the configuration does not take effect.

    After devices in the ERPS rings receive topology change notification messages from an ERPS ring, they send Flush-FDB messages on their own rings to instruct other devices in the rings to delete MAC addresses and learn new MAC addresses to ensure nonstop traffic transmission.

  4. (Optional) Set the topology change protection interval to suppress topology change notification messages.

    tc-protection interval interval-value

  5. (Optional) Set the maximum number of topology change notification messages that devices in an ERPS ring can process within the topology change protection interval.

    tc-protection threshold threshold-value

    The topology change protection interval is specified using the tc-protection interval command.

(Optional) Configuring the ERPS Protection Switching Function

Context

To ensure that an ERPS ring function properly when a node or link fails, configure the switching mode, port blocking mode, and timers.

Procedure

  1. Enter the system view.

    system-view

  2. Enter the view of a created ERPS ring.

    erps ring ring-id

  3. Configure the revertive or non-revertive switching mode for the ERPS ring.

    revertive { enable | disable }

    By default, an ERPS ring works in revertive switching mode.

  4. Exit the ERPS ring view to enter the system view.

    quit

  5. Enter the view of a port to be blocked.

    interface interface-type interface-number

  6. Configure the port blocking mode.

    erps ring ring-id protect-switch { force | manual }

    The ERPS ring specified by ring ring-id must be the one to which the port is added.

    To cancel port blocking, run the clear command in the ERPS ring view.

  7. Exit the ERPS ring view to enter the system view.

    quit

(Optional) Configuring the Self-Healing Function for an ERPS Ring

Context

On a stable ERPS ring, if a node where the RPL owner port does not reside incorrectly sends R-APS SF messages when no fault occurs, the RPL owner port may be unblocked, causing a loop. After the self-healing function is enabled, the device eliminates the loop caused by incorrectly sent messages through status detection.

Procedure

  1. Enter the system view.

    system-view

  2. Enter the view of a created ERPS ring.

    erps ring ring-id

  3. Disable the self-healing function for the ERPS ring.

    erps self-heal disable

    By default, this function is enabled.

Verifying the ERPSv2 Configuration

Procedure

  1. Run the display erps [ ring ring-id ] [ verbose ] command to check device ports added to an ERPS ring and ERPS ring configurations.
  2. Run the display erps interface interface-type interface-number [ ring ring-id ] command to check the physical status of ports added to an ERPS ring.

Example for Configuring ERPSv2

Networking Requirements

Redundant links are usually used on an Ethernet switched network to provide link backup and improve network reliability. The use of redundant links, however, may cause loops on the switched network, leading to broadcast storms and unstable MAC address entries. As a result, the communication quality deteriorates, and communication services may even be interrupted. ERPS can be configured on devices on a ring network to prevent loops caused by redundant links. As a Layer 2 loop prevention protocol defined by the ITU-T, ERPS provides fast convergence that can meet carrier-class reliability requirements. In addition to loop prevention, ERPSv2 supports functions including multi-ring networking and setting the revertive switching mode. It is applicable to more networking scenarios when improving network reliability.

In Figure 7-13, DeviceA, DeviceB, DeviceC, and DeviceD constitute a major ring, and DeviceA, LSW1, LSW2, LSW3, and DeviceD constitute a sub-ring.

Figure 7-13 ERPS multi-ring networking

In this example, interface 1, interface 2, and interface 3 represent GE1/0/1, GE1/0/2, and GE1/0/3, respectively.


Configuration Roadmap

The configuration roadmap is as follows:

  1. Set the link type of all ports to be added to an ERPS ring to trunk.

  2. Create ERPS rings and configure control VLANs and ERP instances.

  3. Configure the ERPS version and configure an ERPS ring as a sub-ring.

  4. Add Layer 2 ports to ERPS rings and configure port roles.

  5. Configure the topology change notification and topology change protection functions.

  6. Configure the Guard timer and WTR timer for ERPS rings.

  7. Configure the Layer 2 forwarding function on DeviceA through DeviceD and LSW1 through LSW3.

Procedure

  1. Set the link type of all ports to be added to an ERPS ring to trunk.

    # Configure DeviceA. The configurations of DeviceB, DeviceC, DeviceD, LSW1, LSW2, and LSW3 are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    <HUAWEI> system-view
[HUAWEI] sysname DeviceA
[DeviceA] interface ge 1/0/1
[DeviceA-GE1/0/1] port link-type trunk
[DeviceA-GE1/0/1] quit
[DeviceA] interface ge 1/0/2
[DeviceA-GE1/0/2] port link-type trunk
[DeviceA-GE1/0/2] quit
[DeviceA] interface ge 1/0/3
[DeviceA-GE1/0/3] port link-type trunk
[DeviceA-GE1/0/3] quit

  2. Create ERPS ring 1 and ERPS ring 2 and configure ERP instances for the two rings. Set the control VLAN ID of ERPS ring 1 to 10 and the control VLAN ID of ERPS ring 2 to 20. Enable ERPS rings 1 and 2 to transmit data packets from VLANs 100 to 200.

    # Configure DeviceA. The configurations of DeviceB, DeviceC, DeviceD, LSW1, LSW2, and LSW3 are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    [DeviceA] stp region-configuration
[DeviceA-mst-region] instance 1 vlan 10 20 100 to 200
[DeviceA-mst-region] quit
[DeviceA] erps ring 1
[DeviceA-erps-ring1] control-vlan 10
[DeviceA-erps-ring1] protected-instance 1
[DeviceA-erps-ring1] quit
[DeviceA] erps ring 2
[DeviceA-erps-ring2] control-vlan 20
[DeviceA-erps-ring2] protected-instance 1
[DeviceA-erps-ring2] quit

  3. Configure ERPSv2 and configure ERPS ring 2 as a sub-ring.

    # Configure DeviceA. The configurations of DeviceB, DeviceC, DeviceD, LSW1, LSW2, and LSW3 are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    [DeviceA] erps ring 1
[DeviceA-erps-ring1] version v2
[DeviceA-erps-ring1] quit
[DeviceA] erps ring 2
[DeviceA-erps-ring2] version v2
[DeviceA-erps-ring2] sub-ring
[DeviceA-erps-ring2] quit

  4. Add Layer 2 ports to ERPS rings and configure port roles. Configure GE1/0/1 on DeviceB and GE1/0/2 on LSW3 as their respective RPL owner ports.

    # Configure DeviceA. The configurations of DeviceC, DeviceD, LSW1, and LSW2 are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    [DeviceA] interface ge 1/0/1
[DeviceA-GE1/0/1] stp disable
[DeviceA-GE1/0/1] erps ring 2
[DeviceA-GE1/0/1] quit
[DeviceA] interface ge 1/0/2
[DeviceA-GE1/0/2] stp disable
[DeviceA-GE1/0/2] erps ring 1
[DeviceA-GE1/0/2] quit
[DeviceA] interface ge 1/0/3
[DeviceA-GE1/0/3] stp disable
[DeviceA-GE1/0/3] erps ring 1
[DeviceA-GE1/0/3] quit

    # Configure DeviceB. The configuration of LSW3 is similar to that of DeviceB. For detailed configurations, see Configuration Scripts.

    [DeviceB] interface ge 1/0/1
[DeviceB-GE1/0/1] stp disable
[DeviceB-GE1/0/1] erps ring 1 rpl owner
[DeviceB-GE1/0/1] quit
[DeviceB] interface ge 1/0/2
[DeviceB-GE1/0/2] stp disable
[DeviceB-GE1/0/2] erps ring 1
[DeviceB-GE1/0/2] quit

  5. Configure the topology change notification and topology change protection functions on interconnected nodes DeviceA and DeviceD.

    # Configure DeviceA. The configuration of DeviceD is similar to that of DeviceA. For detailed configurations, see Configuration Scripts.

    [DeviceA] erps ring 1
[DeviceA-erps-ring1] tc-protection interval 200
[DeviceA-erps-ring1] tc-protection threshold 60
[DeviceA-erps-ring1] quit
[DeviceA] erps ring 2
[DeviceA-erps-ring2] tc-notify erps ring 1
[DeviceA-erps-ring2] quit

  6. Configure the Guard timer and WTR timer for ERPS rings.

    # Configure DeviceA. The configurations of DeviceB, DeviceC, DeviceD, LSW1, LSW2, and LSW3 are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    [DeviceA] erps ring 1
[DeviceA-erps-ring1] wtr-timer 6
[DeviceA-erps-ring1] guard-timer 100
[DeviceA-erps-ring1] quit
[DeviceA] erps ring 2
[DeviceA-erps-ring2] wtr-timer 6
[DeviceA-erps-ring2] guard-timer 100
[DeviceA-erps-ring2] quit

  7. Configure the Layer 2 forwarding function on DeviceA through DeviceD and LSW1 through LSW3.

    # Configure DeviceA. The configurations of DeviceB, DeviceC, DeviceD, LSW1, LSW2, and LSW3 are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    [DeviceA] vlan batch 100 to 200
[DeviceA] interface ge 1/0/1
[DeviceA-GE1/0/1] undo port trunk allow-pass vlan 1
[DeviceA-GE1/0/1] port trunk allow-pass vlan 100 to 200
[DeviceA-GE1/0/1] quit
[DeviceA] interface ge 1/0/2
[DeviceA-GE1/0/2] undo port trunk allow-pass vlan 1
[DeviceA-GE1/0/2] port trunk allow-pass vlan 100 to 200 
[DeviceA-GE1/0/2] quit
[DeviceA] interface ge 1/0/3
[DeviceA-GE1/0/3] undo port trunk allow-pass vlan 1
[DeviceA-GE1/0/3] port trunk allow-pass vlan 100 to 200
[DeviceA-GE1/0/3] quit

  8. Verify the configuration.

    # After the network becomes stable, run the display erps command to check brief information about the ERPS ring and ports added to the ERPS ring. The following example uses the command output on DeviceB.

    [DeviceB] display erps
D  : Discarding
F  : Forwarding
R  : RPL Owner
N  : RPL Neighbour
FS : Forced Device
MS : Manual Device
Total number of rings configured = 1
Ring  Control  WTR Timer  Guard Timer  Port 1               Port 2
ID    VLAN     (min)      (csec)
--------------------------------------------------------------------------------
   1       10          6          100  (D,R)GE1/0/1         (F)GE1/0/2
--------------------------------------------------------------------------------

    # Run the display erps verbose command to check detailed information about the ERPS ring and ports added to the ERPS ring.

    [DeviceB] display erps verbose
Ring ID                             : 1
Description                         : Ring 1
Control Vlan                        : 10
Protected Instance                  : 1 
Service Vlan                        : 100 to 200
WTR Timer Setting (min)             : 6      Running (s)           : 0  
Guard Timer Setting (csec)          : 100    Running (csec)        : 0  
Holdoff Timer Setting (deciseconds) : 0      Running (deciseconds) : 0  
WTB Timer Running (csec)            : 0  
Ring State                          : Idle
RAPS_MEL                            : 7
Revertive Mode                      : Revertive
R-APS Channel Mode                  : -
Version                             : 2
Sub-ring                            : No 
Forced Device Port                  : -
Manual Device Port                  : -
TC-Notify                           : -
Time since last topology change     : 0 days 4h:12m:20s
 
--------------------------------------------------------------------------------
Port                Port Role     Port Status     Signal Status
--------------------------------------------------------------------------------
GE1/0/1             RPL Owner     Discarding      Non-failed      
GE1/0/2             Common        Forwarding      Non-failed

Configuration Scripts

  • DeviceA

    #
sysname DeviceA
#
vlan batch 100 to 200
#
stp region-configuration
 instance 1 vlan 10 20 100 to 200
#
erps ring 1
 control-vlan 10
 protected-instance 1
 wtr-timer 6
 guard-timer 100
 version v2
 tc-protection interval 200
 tc-protection threshold 60
erps ring 2
 control-vlan 20
 protected-instance 1
 wtr-timer 6
 guard-timer 100
 version v2
 sub-ring
 tc-notify erps ring 1
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 20 100 to 200
 stp disable
 erps ring 2
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200
 stp disable
 erps ring 1
#
interface ge 1/0/3
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200
 stp disable
 erps ring 1
#
return

  • DeviceB

    #
sysname DeviceB
#
vlan batch 100 to 200
#
stp region-configuration
 instance 1 vlan 10 100 to 200
#
erps ring 1
 control-vlan 10
 protected-instance 1
 wtr-timer 6
 guard-timer 100
 version v2
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200
 stp disable
 erps ring 1 rpl owner
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200
 stp disable
 erps ring 1
#
return

  • DeviceC

    #
sysname DeviceC
#
vlan batch 100 to 200
#
stp region-configuration
 instance 1 vlan 10 100 to 200
#
erps ring 1
 control-vlan 10
 protected-instance 1
 wtr-timer 6
 guard-timer 100
 version v2
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200
 stp disable
 erps ring 1
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200
 stp disable
 erps ring 1
#
return

  • DeviceD

    #
sysname DeviceD
#
vlan batch 100 to 200
#
stp region-configuration
 instance 1 vlan 10 20 100 to 200
#
erps ring 1
 control-vlan 10
 protected-instance 1
 wtr-timer 6
 guard-timer 100
 version v2
 tc-protection interval 200
 tc-protection threshold 60
erps ring 2
 control-vlan 20
 protected-instance 1
 wtr-timer 6
 guard-timer 100
 version v2
 sub-ring
 tc-notify erps ring 1
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 20 100 to 200
 stp disable
 erps ring 2
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200
 stp disable
 erps ring 1
#
interface ge 1/0/3
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 100 to 200
 stp disable
 erps ring 1
#
return

  • LSW1

    #
sysname LSW1
#
vlan batch 100 to 200
#
stp region-configuration
 instance 1 vlan 20 100 to 200
#
erps ring 2
 control-vlan 20
 protected-instance 1
 wtr-timer 6
 guard-timer 100
 version v2
 sub-ring
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 20 100 to 200
 stp disable
 erps ring 2
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 20 100 to 200
 stp disable
 erps ring 2
#
return

  • LSW2

    #
sysname LSW2
#
vlan batch 100 to 200
#
stp region-configuration
 instance 1 vlan 20 100 to 200
#
erps ring 2
 control-vlan 20
 protected-instance 1
 wtr-timer 6
 guard-timer 100
 version v2
 sub-ring
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 20 100 to 200
 stp disable
 erps ring 2
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 20 100 to 200
 stp disable
 erps ring 2
#
return

  • LSW3

    #
sysname LSW3
#
vlan batch 100 to 200
#
stp region-configuration
 instance 1 vlan 20 100 to 200
#
erps ring 2
 control-vlan 20
 protected-instance 1
 wtr-timer 6
 guard-timer 100
 version v2
 sub-ring
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 20 100 to 200
 stp disable
 erps ring 2
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 20 100 to 200
 stp disable
 erps ring 2 rpl owner
#
return

Configuring Timers for an ERPS Ring

Context

To prevent network flapping after a faulty node or link on an ERPS ring recovers, the device starts timers to reduce the traffic interruption time in the ERPS ring.

Procedure

  1. Enter the system view.

    system-view

  2. Enter the view of a created ERPS ring.

    erps ring ring-id

  3. Configure the WTR timer, Guard timer, and Holdoff timer for the ERPS ring as required.

    Table 7-9 Configuring timers for an ERPS ring

    Operation

    Command

    Description

    Configuring the WTR timer for an ERPS ring

    wtr-timer time-value

    By default, the WTR timer is 5 minutes in an ERPS ring.

    Configuring the Guard timer for an ERPS ring

    guard-timer time-value

    By default, the Guard timer is 200 centiseconds in an ERPS ring.

    Configuring the Holdoff timer for an ERPS ring

    holdoff-timer time-value

    By default, the Holdoff timer is 0 deciseconds in an ERPS ring.

    For details about the differences between timers, see Timers.

Configuring the MEL Value for an ERPS Ring

Context

On a Layer 2 network running ERPS, if another fault detection protocol (for example, CFM) is configured, the MEL field in R-APS PDUs can be used to determine whether the R-APS PDUs can be forwarded. If the MEL value configured for an ERPS ring is smaller than the MEL value in packets of the fault detection protocol, the R-APS PDUs cannot be forwarded. Otherwise, the R-APS PDUs can be forwarded. The MEL value can also be used for communication with non-Huawei devices. The same MEL value ensures smooth communication between devices.

Procedure

  1. Enter the system view.

    system-view

  2. Enter the view of a created ERPS ring.

    erps ring ring-id

  3. Configure the MEL value for the ERPS ring.

    raps-mel level-id

    By default, the value of the MEL field in R-APS PDUs is 7.

Configuring ERPS Multi-Instance

Understanding ERPS Multi-Instance

ERPS multi-instance allows multiple logical ERPS rings to be configured on a physical ring. On a common ERPS network, a physical ring can be configured with only one ERPS ring and only one blocked port can be specified. When the ERPS ring is complete, the blocked port prevents all user packets from passing through. As a result, all user packets are transmitted over only one path on the ERPS ring, and the link on the other side of the blocked port becomes idle, wasting bandwidth resources. After ERPS multi-instance is configured, each ERPS ring can be configured with one or more ERP instances. Each ERP instance represents a VLAN range. Each blocked port is valid only for the VLANs protected by the local ERPS ring. Traffic from different VLANs can be transmitted through different paths. In this way, traffic load balancing and link backup are implemented, preventing bandwidth resource waste and improving bandwidth utilization.

In Figure 7-14, DeviceA, DeviceB, DeviceC, DeviceD, and DeviceE constitute a physical ring. ERPS Ring1 and ERPS Ring2 are configured for the physical ring. Interface1 is the blocked port in ERPS Ring1. The VLANs mapped to the ERP instance are VLANs 100 to 200. Interface2 is the blocked port in ERPS Ring2. The VLANs mapped to the ERP instance are VLANs 300 to 400. After the configuration is complete, data packets from VLAN 100 to VLAN 200 are forwarded along the path shown in data flow 1, and data packets from VLAN 300 to VLAN 400 are forwarded along the path shown in data flow 2. This implements load balancing and improves link utilization.
Figure 7-14 ERPS multi-instance networking

Creating an ERPS Ring

Context

ERPS works for ERPS rings. An ERPS ring consists of connected Layer 2 switching devices that are configured with the same control VLAN and data VLAN. Before configuring other ERPS functions, create an ERPS ring.

Procedure

  1. Enter the system view.

    system-view

  2. Create an ERPS ring and enter the ERPS ring view.

    erps ring ring-id

  3. (Optional) Enable the function of encapsulating an ERPS ring ID into the destination MAC address of R-APS PDUs.

    encapsulate-ring-id enable

    By default, the function of encapsulating an ERPS ring ID into the destination MAC address of R-APS PDUs is disabled.

  4. (Optional) Configure a description.

    description description

    By default, the description of an ERPS ring is the ERPS ring name, for example, Ring 1.

Configuring a Control VLAN

Context

Control and data VLANs have different functions. On an ERPS ring, a control VLAN is used to transmit only R-APS PDUs but not user service packets, which improves ERPS security. All the devices on an ERPS ring must be configured with the same control VLAN. Different ERPS rings cannot use the same control VLAN.

Procedure

  1. Enter the system view.

    system-view

  2. Enter the view of a created ERPS ring.

    erps ring ring-id

  3. Configure a control VLAN for the ERPS ring.

    control-vlan vlan-id

    • If you run the control-vlan command multiple times, only the latest configuration takes effect.
    • The control VLAN specified by the vlan-id parameter must be a VLAN that has not been created or used.
    • If ports have been added to the ERPS ring, the control VLAN cannot be changed. To delete a configured control VLAN, you must run the undo erps ring command in the interface view or the undo port command in the ERPS ring view to remove the ports from the ERPS ring, and then run the undo control-vlan command to delete the control VLAN.
    • After a control VLAN is created, the vlan batch vlan-id1 [ to vlan-id2 ] &<1-10> command is automatically displayed in the configuration file.
    • After a port is added to an ERPS ring configured with a control VLAN, the port is automatically added to the control VLAN. If the port is a trunk port, the port trunk allow-pass vlan vlan-id command is automatically displayed in the view of the port in the configuration file. If the port is a hybrid port, the port hybrid tagged vlan vlan-id command is automatically displayed in the view of the port in the configuration file.

Configuring an ERP Instance and Activating the Mapping Between the ERP Instance and a VLAN

Context

On a Layer 2 device running ERPS, the VLANs in which R-APS PDUs and data packets are transmitted must be mapped to an ERP instance so that ERPS forwards or blocks the packets based on blocking rules. Otherwise, the preceding packets may cause broadcast storms on the ring network, causing the network to become unavailable.

Procedure

  1. Enter the system view.

    system-view

  2. Enter the ERPS ring view.

    erps ring ring-id

  3. Create an ERP instance for the ERPS ring.

    protected-instance { all | { instance-id1 [ to instance-id2 ] } &<1-10> }

    By default, no ERP instance is configured for an ERPS ring.

    • If the stp mode command has been run in the system view to set the STP working mode to VBST, the ERP instance configured using the protected-instance command must be a created static instance.

    • If you run the protected-instance command multiple times in the same ERPS ring, multiple ERP instances are configured.

    • If ports have been added to the ERPS ring, the ERP instance cannot be changed. To delete a configured ERP instance, you must run the undo erps ring command in the interface view or the undo port command in the ERPS ring view to remove the ports from the ERPS ring, and then run the undo protected-instance command to delete the ERP instance.

  4. Exit the ERPS ring view to enter the system view.

    quit

  5. Configure the mapping between the ERP instance and a VLAN.
    1. Enter the MST region view.

      stp region-configuration

    2. Configure the mapping between the ERP instance and a VLAN.

      instance instance-id vlan { vlan-id1 [ to vlan-id2 ] } &<1-10>

      By default, all VLANs in an MST region are mapped to instance 0.

      The value of the instance-id parameter must be the same as the value of the instance-id parameter specified in the protected-instance command.

      • A VLAN cannot be mapped to multiple instances. If you map a VLAN that has been mapped to an instance to another instance, the original mapping is deleted.

      • The vlan-mapping modulo modulo command configures mappings between MSTIs and VLANs based on a default algorithm. However, the mappings configured using this command cannot meet the actual requirements. Therefore, this command is not recommended.

      • To configure the mapping between an ERP instance and a MUX VLAN, you are advised to configure the principal VLAN, group VLANs, and separate VLANs of the MUX VLAN to map the same ERP instance. Otherwise, loops may occur.

Adding a Layer 2 Port to an ERPS Ring and Configuring the Port Role

Prerequisites

Before adding a Layer 2 port to an ERPS ring and configuring the port role, you have completed the following tasks:

  • Disable STP and Smart Link on the Layer 2 port to be added to the ERPS ring.
    • If STP has been enabled on the port, run the stp disable command in the interface view to disable STP.
    • If Smart Link has been enabled on the port, run the undo port command in the Smart Link group view to disable Smart Link.

  • Run the control-vlan command to configure a control VLAN and the protected-instance command to configure an ERP instance.

Context

After an ERPS ring is created, add Layer 2 ports to the ERPS ring and configure the port roles so that ERPS can work properly.

Use either of the following methods to add a Layer 2 port to an ERPS ring and configure the port role:

  • In the ERPS ring view, add a specified port to the ERPS ring and configure the port role.

  • In the interface view, add the port to an ERPS ring and configure the port role.

  • An ERPS-enabled port must be configured as a trunk or hybrid port because it needs to allow packets from both the control VLAN and data VLAN to pass through.

  • Currently, packets for updating MAC addresses cannot be sent separately. Therefore, it is not recommended that a direct link between two upstream nodes be configured as the RPL.

  • Before changing the port role, run the shutdown command to shut down the port. After the port role is changed, run the undo shutdown command to enable the port. Otherwise, traffic cannot be forwarded.

  • Before adding a port to an ERPS ring, disable port security on the port. Otherwise, loops cannot be prevented.

Procedure

  1. Enter the system view.

    system-view

  2. Add a Layer 2 port to an ERPS ring.

    • In the ERPS ring view, add a specified port to the ERPS ring and configure the port role.
      interface interface-type interface-number
stp disable
port link-type trunk
port trunk allow-pass vlan { { vlan-id1 [ to vlan-id2 ] }&<1-10> | all }
quit
erps ring ring-id
port interface-type interface-number [ rpl owner ]
    • In the interface view, add the port to an ERPS ring and configure the port role.
      interface interface-type interface-number
stp disable
port link-type trunk
port trunk allow-pass vlan { { vlan-id1 [ to vlan-id2 ] }&<1-10> | all }
erps ring ring-id [ rpl owner ]

Verifying the ERPS Multi-Instance Configuration

Procedure

  1. Run the display erps [ ring ring-id ] [ verbose ] command to check device ports added to an ERPS ring and ERPS ring configurations.
  2. Run the display erps interface interface-type interface-number [ ring ring-id ] command to check the physical status of ports added to an ERPS ring.

Example for Configuring ERPS Multi-Instance

Networking Requirements

On an ERPS network, a physical ring can be configured with only one ERPS ring and only one blocked port can be specified. When the ERPS ring is complete, the blocked port prevents all user packets from passing through. As a result, all user packets are transmitted over only one path on the ERPS ring, and the link on the other side of the blocked port becomes idle, wasting bandwidth resources.

In Figure 7-15, two ERPS instances, ERPS ring 1 and ERPS ring 2, are configured on DeviceA through DeviceD. P1 on DeviceB is a blocked port on ERPS ring 1, and P2 on DeviceA is a blocked port on ERPS ring 2, implementing load balancing and link backup.

Figure 7-15 ERPS single-ring multi-instance networking

In this example, interface 1 and interface 2 represent GE1/0/1 and GE1/0/2, respectively.


Configuration Roadmap

The configuration roadmap is as follows:

  1. Set the link type of all ports to be added to an ERPS ring to trunk.

  2. Create ERPS rings and configure control VLANs and ERP instances.

  3. Add Layer 2 ports to ERPS rings and configure port roles.

  4. Configure the Guard timer and WTR timer for ERPS rings.

  5. Configure the Layer 2 forwarding function on DeviceA through DeviceD.

Procedure

  1. Set the link type of all ports to be added to an ERPS ring to trunk.

    # Configure DeviceA. The configurations of DeviceB, DeviceC, and DeviceD are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    <HUAWEI> system-view
[HUAWEI] sysname DeviceA
[DeviceA] interface ge 1/0/1
[DeviceA-GE1/0/1] port link-type trunk
[DeviceA-GE1/0/1] quit
[DeviceA] interface ge 1/0/2
[DeviceA-GE1/0/2] port link-type trunk
[DeviceA-GE1/0/2] quit

  2. Create ERPS ring 1 and ERPS ring 2 and configure ERP instances for the two rings. Set the control VLAN ID of ERPS ring 1 to 10 and the control VLAN ID of ERPS ring 2 to 20. Enable ERPS ring 1 to transmit data packets from VLANs 100 to 200 and ERPS ring 2 to transmit data packets from VLANs 300 to 400.

    # Configure DeviceA. The configurations of DeviceB, DeviceC, and DeviceD are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    [DeviceA] erps ring 1
[DeviceA-erps-ring1] control-vlan 10
[DeviceA-erps-ring1] protected-instance 1
[DeviceA-erps-ring1] quit
[DeviceA] stp region-configuration
[DeviceA-mst-region] instance 1 vlan 10 100 to 200
[DeviceA-mst-region] quit
[DeviceA] erps ring 2
[DeviceA-erps-ring2] control-vlan 20
[DeviceA-erps-ring2] protected-instance 2
[DeviceA-erps-ring2] quit
[DeviceA] stp region-configuration
[DeviceA-mst-region] instance 2 vlan 20 300 to 400
[DeviceA-mst-region] quit

  3. Add Layer 2 ports to ERPS rings and configure port roles. Configure GE1/0/1 on DeviceA and GE1/0/2 on DeviceB as their respective RPL owner ports.

    # Configure DeviceA.

    [DeviceA] interface ge 1/0/1
[DeviceA-GE1/0/1] stp disable
[DeviceA-GE1/0/1] erps ring 1
[DeviceA-GE1/0/1] erps ring 2 rpl owner
[DeviceA-GE1/0/1] quit
[DeviceA] interface ge 1/0/2
[DeviceA-GE1/0/2] stp disable
[DeviceA-GE1/0/2] erps ring 1
[DeviceA-GE1/0/2] erps ring 2
[DeviceA-GE1/0/2] quit
    # Configure DeviceB.
    [DeviceB] interface ge 1/0/1
[DeviceB-GE1/0/1] stp disable
[DeviceB-GE1/0/1] erps ring 1
[DeviceB-GE1/0/1] erps ring 2
[DeviceB-GE1/0/1] quit
[DeviceB] interface ge 1/0/2
[DeviceB-GE1/0/2] stp disable
[DeviceB-GE1/0/2] erps ring 1 rpl owner
[DeviceB-GE1/0/2] erps ring 2
[DeviceB-GE1/0/2] quit

    # Configure DeviceC. The configuration of DeviceD is similar to that of DeviceC. For detailed configurations, see Configuration Scripts.

    [DeviceC] interface ge 1/0/1
[DeviceC-GE1/0/1] stp disable
[DeviceC-GE1/0/1] erps ring 1
[DeviceC-GE1/0/1] erps ring 2
[DeviceC-GE1/0/1] quit
[DeviceC] interface ge 1/0/2
[DeviceC-GE1/0/2] stp disable
[DeviceC-GE1/0/2] erps ring 1
[DeviceC-GE1/0/2] erps ring 2
[DeviceC-GE1/0/2] quit

  4. Configure the Guard timer and WTR timer for ERPS rings.

    # Configure DeviceA. The configurations of DeviceB, DeviceC, and DeviceD are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    [DeviceA] erps ring 1
[DeviceA-erps-ring1] wtr-timer 6
[DeviceA-erps-ring1] guard-timer 100
[DeviceA-erps-ring1] quit
[DeviceA] erps ring 2
[DeviceA-erps-ring2] wtr-timer 6
[DeviceA-erps-ring2] guard-timer 100
[DeviceA-erps-ring2] quit

  5. Configure the Layer 2 forwarding function on DeviceA through DeviceD.

    # Configure DeviceA. The configurations of DeviceB, DeviceC, and DeviceD are similar to the configuration of DeviceA. For detailed configurations, see Configuration Scripts.

    [DeviceA] vlan batch 100 to 200 300 to 400
[DeviceA] interface ge 1/0/1
[DeviceA-GE1/0/1] undo port trunk allow-pass vlan 1
[DeviceA-GE1/0/1] port trunk allow-pass vlan 100 to 200 300 to 400
[DeviceA-GE1/0/1] quit
[DeviceA] interface ge 1/0/2
[DeviceA-GE1/0/2] undo port trunk allow-pass vlan 1
[DeviceA-GE1/0/2] port trunk allow-pass vlan 100 to 200 300 to 400
[DeviceA-GE1/0/2] quit

  6. Verify the configuration.

    # After the network becomes stable, run the display erps command to check brief information about the ERPS ring and ports added to the ERPS ring. The following example uses the command output on DeviceB.

    [DeviceB] display erps
D : Discarding
F : Forwarding
R : RPL Owner
N  : RPL Neighbour
FS : Forced Device
MS : Manual Device
Total number of rings configured = 2
Ring  Control  WTR Timer  Guard Timer  Port 1              Port 2
ID    VLAN     (min)      (csec)
--------------------------------------------------------------------------------
   1       10          6          100  (F)GE1/0/1          (D,R)GE1/0/2
   2       20          6          100  (F)GE1/0/1          (F)GE1/0/2
--------------------------------------------------------------------------------

    # Run the display erps verbose command to check detailed information about the ERPS ring and ports added to the ERPS ring. The following example uses the command output on DeviceB.

    [DeviceB] display erps verbose
Ring ID                             : 1
Description                         : Ring 1
Control Vlan                        : 10
Protected Instance                  : 1
Service Vlan                        : 100 to 200
WTR Timer Setting (min)             : 6      Running (s)           : 0
Guard Timer Setting (csec)          : 100    Running (csec)        : 0
Holdoff Timer Setting (deciseconds) : 0      Running (deciseconds) : 0
WTB Timer Running (csec)            : 0
Ring State                          : Idle
RAPS_MEL                            : 7
Revertive Mode                      : Revertive
R-APS Channel Mode                  : -
Version                             : 1
Sub-ring                            : No
Forced Device Port                  : -
Manual Device Port                  : -
TC-Notify                           : -
Time since last topology change     : 0 days 0h:35m:5s
 
--------------------------------------------------------------------------------
Port                Port Role     Port Status     Signal Status
--------------------------------------------------------------------------------
GE1/0/1             Common        Forwarding      Non-failed
GE1/0/2             RPL Owner     Discarding      Non-failed

Ring ID                             : 2
Description                         : Ring 2
Control Vlan                        : 20
Protected Instance                  : 2
Service Vlan                        : 300 to 400
WTR Timer Setting (min)             : 6      Running (s)           : 0
Guard Timer Setting (csec)          : 100    Running (csec)        : 0
Holdoff Timer Setting (deciseconds) : 0      Running (deciseconds) : 0
WTB Timer Running (csec)            : 0
Ring State                          : Idle
RAPS_MEL                            : 7
Revertive Mode                      : Revertive
R-APS Channel Mode                  : -
Version                             : 1
Sub-ring                            : No 
Forced Device Port                  : -
Manual Device Port                  : -
TC-Notify                           : -
Time since last topology change     : 0 days 0h:35m:30s
--------------------------------------------------------------------------------
Port                Port Role     Port Status     Signal Status
--------------------------------------------------------------------------------
GE1/0/1             Common        Forwarding      Non-failed
GE1/0/2             Common        Forwarding      Non-failed

Configuration Scripts

  • DeviceA

    #
sysname DeviceA
#
vlan batch 10 20 100 to 200 300 to 400
#
stp region-configuration
 instance 1 vlan 10 100 to 200
 instance 2 vlan 20 300 to 400
#
erps ring 1
 control-vlan 10
 protected-instance 1
 wtr-timer 6
 guard-timer 100
erps ring 2
 control-vlan 20
 protected-instance 2
 wtr-timer 6
 guard-timer 100
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 20 100 to 200 300 to 400
 stp disable
 erps ring 1
 erps ring 2 rpl owner
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 20 100 to 200 300 to 400
 stp disable
 erps ring 1
 erps ring 2
#
return

  • DeviceB

    #
sysname DeviceB
#
vlan batch 10 20 100 to 200 300 to 400
#
stp region-configuration
 instance 1 vlan 10 100 to 200
 instance 2 vlan 20 300 to 400
#
erps ring 1
 control-vlan 10
 protected-instance 1
 wtr-timer 6
 guard-timer 100
erps ring 2
 control-vlan 20
 protected-instance 2
 wtr-timer 6
 guard-timer 100
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 20 100 to 200 300 to 400
 stp disable
 erps ring 1
 erps ring 2
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 20 100 to 200 300 to 400
 stp disable
 erps ring 1 rpl owner
 erps ring 2
#
return

  • DeviceC

    #
sysname DeviceC
#
vlan batch 10 20 100 to 200 300 to 400
#
stp region-configuration
 instance 1 vlan 10 100 to 200
 instance 2 vlan 20 300 to 400
#
erps ring 1
 control-vlan 10
 protected-instance 1
 wtr-timer 6
 guard-timer 100
erps ring 2
 control-vlan 20
 protected-instance 2
 wtr-timer 6
 guard-timer 100
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 20 100 to 200 300 to 400
 stp disable
 erps ring 1
 erps ring 2
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 20 100 to 200 300 to 400
 stp disable
 erps ring 1
 erps ring 2
#
return

  • DeviceD

    #
sysname DeviceD
#
vlan batch 10 20 100 to 200 300 to 400
#
stp region-configuration
 instance 1 vlan 10 100 to 200
 instance 2 vlan 20 300 to 400
#
erps ring 1
 control-vlan 10
 protected-instance 1
 wtr-timer 6
 guard-timer 100
erps ring 2
 control-vlan 20
 protected-instance 2
 wtr-timer 6
 guard-timer 100
#
interface ge 1/0/1
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 20 100 to 200 300 to 400
 stp disable
 erps ring 1
 erps ring 2
#
interface ge 1/0/2
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 10 20 100 to 200 300 to 400
 stp disable
 erps ring 1
 erps ring 2
#
return

Maintaining ERPS

Context

Before collecting ERPS statistics again, run the reset erps command to clear existing ERPS statistics.

ERPS statistics cannot be restored after they are cleared. Exercise caution when running this command.

Procedure

  1. Clear packet statistics in an ERPS ring in the user view.

    reset erps [ ring ring-id ] statistics

Troubleshooting ERPS

Traffic Cannot Be Forwarded in an ERPS Ring

Fault Symptom

After ERPS is configured, service traffic cannot be forwarded because the ERPS ring status is abnormal.

Procedure

  1. Check ERPS ring information on the local device in any view.

    display erps [ ring ring-id ] verbose

    Under normal circumstances, an ERPS ring has only one RPL owner port, other ports are common ports or RPL neighbour ports, and Ring State of each node on the ring is Idle in the command output.

    If the ERPS ring is incomplete or abnormal:

    1. Check whether all devices on the ERPS ring are added to the ERPS ring.
    2. Check whether devices on the ERPS ring have the same ERPS ring configuration, including the ERPS version, major ring, and sub-ring configurations.
    3. Check whether port roles, control VLANs, and ERP instances are correctly configured on all devices on the ERPS ring.
    4. Check whether ports are configured to allow packets from the specified data VLAN to pass through.