ERPS (G.8032) Configuration Commands

Usage Scenario

Precautions

The clear command is supported in both ERPSv1 and ERPSv2.

Usage Scenario

After an ERPS ring is created, run the control-vlan command to create the control VLAN. Unlike a data VLAN, a control VLAN is used only to forward ERPS protocol packets but not forward service packets in an ERPS ring, which improves the security of the ERPS protocol.

Precautions

• If you run the control-vlan command multiple times, only the latest configuration takes effect.

• After a control VLAN is created, the vlan batch { vlan-id1 [ to vlan-id2 ] } &<1-10> command used to create common VLANs is displayed in the configuration file.

• After a port is added to an ERPS ring configured with a control VLAN, the port is added to the control VLAN.

  • If the port is a trunk port, the port trunk allow-pass vlan vlan-id command is displayed in the record of the port that has been added to the ERPS ring in the configuration file.
  • If the port is a hybrid port, the port hybrid tagged vlan vlan-id command is displayed in the record of the port that has been added to the ERPS ring in the configuration file.

• All the devices in an ERPS ring must use the same control VLAN in an ERPS ring, and different ERPS rings must use different control VLANs.

• The control VLAN must be not created, and is not used by other features. In addition, no interface is added to the control VLAN.

• If ports have been added to an ERPS ring, the control VLAN cannot be modified. To delete the configured control VLAN, run the undo erps ring command in the interface view or the undo port command in the ERPS ring view to delete ports from the ERPS ring, and run the undo control-vlan command to delete the control VLAN.

• Run the display erps command to check whether the control VLAN is configured or which VLAN is configured as the control VLAN.

Usage Scenario

You can run the description command on the ERPS-enabled device to configure the description of an ERPS ring. The description contains information such as the ID of the ERPS ring, which facilitates maintenance.

Precautions

If you run the description command multiple times, only the latest configuration takes effect.

After the description is configured in the ERPS ring view, the description only takes effect on the device.

Usage Scenario

You can run the display erps command on the ERPS-enabled device to view ports added to the ERPS ring and information about the ERPS ring. The command output facilitates ERPS management and helps you learn the running status of ports.

Prerequisites

To view information about ports that have been added to a specified ERPS ring and the ERPS ring, ensure that the ERPS ring has already been created.

Precautions

If ring ring-id is not specified, information about all the ERPS rings and ports added to the ERPS rings is displayed.

To check the running status of ports that have been added to an ERPS ring, run the display erps interface command.

Usage Scenario

On a Layer 2 network running ERPS, the display erps statistics command displays statistics about sent and received RAPS PDUs on the ports that are added to ERPS rings. The command output helps you analyze the network situation, learn the network running status, and maintain devices.

Prerequisites

To query statistics about sent and received RAPS PDUs on the ports that have been added to a specified ERPS ring, ensure that the ERPS ring has been created.

The Simple Network Management Protocol (SNMP) is a standard network management protocol widely used on TCP/IP networks. It uses a central computer (a network management station) that runs network management software to manage network elements. The management agent on the network element automatically reports traps to the network management station so that the network administrator can immediately take measures to resolve the problem.

The display snmp-agent trap feature-name erps all command displays trap functions of the ERPS module.

Usage Scenario

Ethernet Ring Protection Switching (ERPS) is a standard protocol issued by the ITU-T to prevent loops on ring networks. ERPS implements fast convergence of carrier-class reliability standards. It allows all ERPS-capable devices on a ring network to communicate.

To enable ERPS on the device, run the erps ring command to create an ERPS ring and enter the ERPS ring view.

To configure parameters such as the control VLAN and the protected instance for an ERPS ring, run the erps ring command to enter the ERPS ring view.

Follow-up Procedure

Run the control-vlan (ERPS ring view) command to configure a control VLAN for the ERPS ring.

Run the protected-instance (ERPS ring view) command to configure an ERP instance for the ERPS ring.

Precautions

To delete an ERPS ring, ensure that no ports are added to the ERPS ring. If any port is added to the ERPS ring, the system displays a message indicating a failure to delete the ERPS ring. To delete an ERPS ring where ports are added, run the undo erps ring command in the interface view or the undo port command in the ERPS ring view to remove the port, and run the undo erps ring command to delete the ERPS ring.

Usage Scenario

After an ERPS ring is created, run the erps ring command in the interface view to add Layer 2 ports to the ERPS ring so that RAPS PDUs can be correctly forwarded. Each device in an ERPS ring is a node, and a maximum of two Layer 2 ports on each node can be added to the same ERPS ring.

Prerequisites

An ERPS ring has been created using the erps ring command.

Precautions

• Before running the undo erps ring command to delete a port from an ERPS ring, run the shutdown (interface view) command to shut down the port. The port can be enabled again according to the actual situation.

• If ports added to an ERPS ring are all ordinary ports, any port on the device with the largest MAC address will be blocked.

• If an RPL neighbour port is configured for a non-virtual channel of a sub-ring, network convergence may fail to meet requirements because SF packets are discarded on the port in the case of a link fault.

Usage Scenario

FS takes precedence over MS.

Prerequisites

Configuration Impact

After an ERPS port is blocked in FS or MS mode, the node on which the ERPS port resides sends RAPS (FS) or RAPS (MS) messages to the other nodes in the ERPS ring. As a result, ERPS performs recalculation and finally unblocks the RPL owner port.

Precautions

The ERPS ring specified by ring-id must be the one to which the port belongs; otherwise, the command does not take effect.

To change the port blocking mode from MS to FS, run the erps ring ring-id protect-switch force command to set the FS mode. To change the port blocking mode from FS to MS, run the clear command in the ERPS ring view to delete the FS mode, and then run the erps ring ring-id protect-switch manual command to set the MS mode.

You can delete the manual port blocking mode only by using the clear command in the ERPS ring view.

The erps ring protect-switch command is not saved in the configuration file.

Usage Scenario

To quickly detect faults, implement fast convergence, and shorten traffic interruptions, run the erps track cfm command to associate ERPS with Ethernet CFM on a port added to an ERPS ring.

Prerequisites

Precautions

This command is supported in both ERPSv1 and ERPSv2.

The association between ERPS and CFM takes effect only when the interface has ERPS associated with CFM and has an interface-based MEP created using the mep mep-id command.

Usage Scenario

On a Layer 2 network running ERPS, after a faulty link or node recovers, the device sends RAPS PDUs to inform the other nodes of link or node recovery and starts the Guard timer. Before the Guard timer expires, the device does not receive any RAPS PDU. If the device receives out-of-date RAPS PDUs indicating that the link or node fails, the local port may be blocked again. After the Guard timer expires, if the device receives an RAPS PDU indicating that another port fails, the local port enters the Forwarding state.

Precautions

If the value of the Guard timer is too small, network loops may occur. The default value of 200 centiseconds is recommended.

Usage Scenario

On Layer 2 networks running ERPS, there may be different requirements for protection switching. For example, on a network where multi-layer services are provided, after a server fails, users may require a period of time to rectify the server fault so that clients do not detect the fault. That is, protection switching is not performed immediately.

You can run the holdoff-timer command to set the Holdoff timer. When a fault occurs, the fault is not immediately reported to ERPS. Instead, the Holdoff timer starts. If the fault persists after the timer expires, the fault will be reported to ERPS.

Precautions

If you run the holdoff-timer command multiple times, only the latest configuration takes effect.

Usage Scenario

After an ERPS ring is created, run the port command to add Layer 2 ports to the ERPS ring so that RAPS PDUs can be correctly forwarded. Each device in an ERPS ring is a node, and a maximum of two Layer 2 ports on each node can be added to the same ERPS ring.

Prerequisites

Precautions

Before deleting a port from an ERPS ring or changing the port role, use the shutdown (interface view) command to disable the port. Then remove the port or change the port role and run the undo shutdown (interface view) command to enable the port. Otherwise, traffic forwarding may fail.

If ports added to an ERPS ring are all ordinary ports, any port on the device with the largest MAC address will be blocked.

Usage Scenario

On a device running ERPS, the VLAN where ERPS PDUs and data packets are transmitted must be mapped to an ERP instance. Otherwise, VLAN packets may cause broadcast storms on the ring network. As a result, the network may become unavailable.

Precautions

• If the stp mode (system view) command is used to set the STP working mode to VLAN-based Spanning Tree (VBST), the ERP instance specified by the protected-instance command must be the 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 modified. To delete the configured ERP instance, run the undo erps ring command in the interface view or the undo port command in the ERPS ring view to delete ports from the ERPS ring, and run the undo protected-instance command to delete the ERP instance.

Follow-up Procedure

Usage Scenario

On a Layer 2 network running ERPS, if another fault detection protocol is enabled, the MEL field in RAPS PDUs is used to determine whether the RAPS PDUs can be forwarded. If the MEL value in an ERPS ring is smaller than the MEL value of the fault detection protocol, the RAPS PDUs have a lower priority and are discarded. If the MEL value in an ERPS ring is larger than the MEL value of the fault detection protocol, the RAPS PDUs can be forwarded. You can run the raps-mel command to set the value of the MEL field in RAPS PDUs.

In addition, the MEL value can also be used for interworking with other vendors' devices in an ERPS ring. The same MEL value ensures smooth communication between devices.

Precautions

If you run the raps-mel command multiple times, only the latest configuration takes effect.

Usage Scenario

Before collecting traffic statistics on a specific interface in a given period of time, clear the existing statistics on the interface by using the reset erps command.

Prerequisites

The ERPS ring has been created, and ports have been added to the specified ERPS ring.

Precautions

The cleared statistics cannot be restored. Exercise caution when you run this command.

Usage Scenario

After link faults in an ERPS ring are rectified, re-blocking the RPL owner port depends on the switching mode:

• In revertive switching, the RPL owner port is re-blocked after the WTR timer expires, and the RPL is blocked.
• In non-revertive switching, the WTR timer is not started, and the original faulty link is still blocked.

Prerequisites

The version v2 command has been executed to specify ERPSv2.

You can specify trap-name to enable the trap function for one or more events of the ERPS module.

Usage Scenario

ERPS has two versions: ERPSv1 and ERPSv2. ERPSv2 supports multi-ring topologies such as intersecting ring topologies in addition to single-ring topologies.

To deploy ERPS on a multi-ring network, run the sub-ring command to configure some rings as sub-rings.

Major rings are closed, and sub-rings are open.

Prerequisites

• The version v2 command has been executed to specify ERPSv2.
• The ERPS ring does not have any port. If the ERPS ring has a port, run the undo erps ring ring-id or undo port interface-type interface-number command to delete the port from the ERPS ring.

Precautions

If a sub-ring uses the VC mode to transmit RAPS PDUs, you must run the virtual-channel disable command to restore the RAPS PDU transmission mode to NVC before running the undo sub-ring command to restore the sub-ring to a major ring.

Usage Scenario

When the topology of the local ERPS ring changes and other ERPS rings is not notified of the topology change, the MAC address entries remain unchanged on the other ERPS rings and therefore user traffic is interrupted. To ensure nonstop traffic transmission, run the tc-notify erps ring command to specify ERPS rings to which topology change notifications are sent.

Prerequisites

The version v2 command has been executed to specify ERPSv2.

Precautions

• The tc-notify erps ring command takes effect only on ERPS sub-rings.

• If an ERPS ring topology changes, the ERPS ring notifies the specified ERPS rings of its topology change. If the ERPS ring that has been specified to receive the topology change notification does not exist, the configuration does not take effect.

• After other ERPS rings receive the topology change notification from an ERPS ring, they send Flush-FDB messages on their separate rings to instruct their nodes to update MAC addresses. This ensures nonstop traffic transmission.

• If the tc-notify erps ring command is run more than once, all configurations take effect.

Usage Scenario

If a user terminal connects to an upper-layer network through multiple ERPS rings and the topology of the ERPS ring closest to the user terminal changes, topology change notifications are doubled when passing through a ring until they reach the upper-layer network. As a result, the upper-layer network receives many identical topology change notifications.

In addition, if an ERPS ring frequently receives topology change notifications, its nodes will have lower CPU processing capability and repeatedly update Flush-FDB packets, consuming much bandwidth. To prevent this problem, run the tc-protection interval command to set the topology change protection interval at which the maximum number of topology change notifications specified in the tc-protection threshold command are processed. Then, during the topology change protection interval, the device processes only the specified maximum number of topology change notification messages. If there are excess notifications, the device processes all the excess notifications once after the topology change protection interval elapses. For example, if the topology change protection interval is set to 10 seconds and the maximum number is set to 5, when a device receives topology change notifications, the device processes only the first 5 topology change notifications within 10 seconds and processes the subsequent topology change notifications only after 10s. This prevents the device from frequently deleting MAC address entries and ARP entries.

Prerequisites

The erps ring command has been executed to create an ERPS ring.

Precautions

Suppressing topology change notification transmission allows the upper-layer network to receive and process only one notification during the topology change protection interval and protects ERPS nodes against topology change (TC) attacks.

Usage Scenario

After a switching device on an ERPS ring network receives topology change notifications, the device updates MAC address entries and ARP entries. Frequent updates will cause a high CPU usage.

To prevent frequent MAC address and ARP entry updates, run the tc-protection threshold command to set the maximum number of topology change notifications that can be processed during the topology change protection interval specified by the tc-protection interval command. Then, during the topology change protection interval, the device processes only the specified maximum number of topology change notification messages. If there are excess notifications, the device processes all the excess notifications once after the topology change protection interval elapses. For example, if the topology change protection interval is set to 10 seconds and the maximum number is set to 5, when a device receives topology change notifications, the device processes only the first 5 topology change notifications within 10 seconds and processes the subsequent topology change notifications only after 10s. This prevents the device from frequently deleting MAC address entries and ARP entries.

Prerequisites

The version v2 command has been run to specify ERPSv2.

Usage Scenario

To configure an ERPS version, run the version command.

Precautions

Before specifying ERPSv1 for an ERPSv2-enabled device, delete all ERPS configurations that ERPSv1 does not support. Otherwise, the version cannot be changed.

Usage Scenario

ERPSv2 supports both single- and multi-ring topologies.

In multi-ring topologies, the VC or NVC mode can be used to transmit RAPS PDUs in a sub-ring:

• VC mode: RAPS PDUs in a sub-ring are transmitted to the major ring by the intersecting node. The RPL owner port of the sub-ring blocks both RAPS PDUs and data traffic.
• NVC mode: RAPS PDUs in a sub-ring are terminated on the intersecting nodes. The RPL owner port of the sub-ring blocks data traffic but not RAPS PDUs.

You can run the virtual-channel command to configure the RAPS PDU transmission mode in a sub-ring.

Prerequisites

Configuration Impact

If a sub-ring uses the VC mode to transmit RAPS PDUs, you must run the virtual-channel disable or undo virtual-channel enable command to restore the RAPS PDU transmission mode to NVC before running the undo sub-ring command to restore the sub-ring to a major ring.

Usage Scenario

Precautions

If you run the wtr-timer command multiple times, only the latest configuration takes effect.