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NE40E-M2 V800R010C10SPC500 Configuration Guide - WAN Access 01

This is NE40E-M2 V800R010C10SPC500 Configuration Guide - WAN Access
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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Configuring a POS Interface

Configuring a POS Interface

You can configure the link layer protocol, clock mode, overhead byte, frame format, and CRC for a POS interface.

Usage Scenario

Before using a POS interface to carry packets, configure parameters for the POS interface.

Pre-configuration Tasks

  • Before configuring a POS interface, power on the Router and ensure that it is working properly.

Configuration Procedure

By default, parameters in POS interface configuration commands use default values. Perform one or more of the following configurations as required.

Configuring the Link Layer Protocol for a POS Interface

The link layer protocol of a POS interface can be configured as PPP or HDLC.

Context

PPP is a link layer protocol used to encapsulate and transmit network layer packets over P2P links. If a bit-oriented link layer protocol is needed for synchronous transmission and no complex services are configured, HDLC can be applied. HDLC does not require that data to be transmitted must be character sets. Instead, it can transparently transmit bit flows of all types, especially the control and response messages. Unlike PPP, HDLC uses authentication protocols to ensure the correctness and connectivity of links to be established. A cyclic redundancy check (CRC) is performed for HDLC frames and information frames are sequentially numbered to ensure reliable transmission. An IP-Trunk can consist of only POS links, and the link layer protocol running on IP-Trunk member interfaces must be HDLC.

Perform the following steps on the Routers:

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run interface pos interface-number

    The POS interface view is displayed.

  3. Run link-protocol { ppp | hdlc }

    A link layer protocol is configured for the POS interface.

  4. Run commit

    The configuration is committed.

Configuring the Clock Mode for a POS Interface

A POS interface works in either master or slave clock mode. You can configure different clock modes for POS interfaces that function as a DTE or DCE.

Context

A POS interface supports the following clock modes:

  • Master clock mode: uses internal clock signals.

  • Slave clock mode: uses line clock signals.

The principles for configuring clock modes for POS interfaces in actual networking are as follows:

  • Clocks modes on the POS interfaces of two directly connected Routers must be both set to master, or on one end set to master and the other end set to slave.

  • If two Routers are connected over a WDM transmission device, clocks modes on the POS interfaces of the two interconnected devices must be both set to master.

  • If two Routers are connected over an active SDH or SONET device, clock modes on the POS interfaces of the two interconnected devices can be set to slave to trace clock signals of the active SDH or SONET device.

  • If the connection mode of two Routers is unknown, the clocks of the POS interfaces on the two Routers must work in master mode.

Perform the following steps on the Routers:

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run interface pos interface-number

    The POS interface view is displayed.

  3. Run clock { master | slave }

    A clock mode is configured for the POS interface.

  4. Run commit

    The configuration is committed.

Configuring Overhead Bytes for a POS Interface

SONET/SDH provides a variety of overhead bytes to implement monitoring at different levels.

Context

C2, the path signal label byte, is contained in the higher-order path overhead. C2 is used to specify the multiplexing structure and the attributes of the information payload in a VC frame.

J0, the regenerator section trace byte, is contained in the section overhead. J0 is used to check the continuity between two ports at the section layer.

J1, the higher-order VC-N path trace byte, is used to check the continuity between two ports at the path layer.

NOTE:

C2, J0, and J1 of the receiver must be the same as those of the transmitter; otherwise, the two ends cannot communicate.

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run interface pos interface-number

    The POS interface view is displayed.

  3. Configure the overhead byte for the POS interface.

    Run the following command as required.

    • Run flag j0 64byte-or-null-mode [ j0-value ] or flag j0 { 16byte-mode | 1byte-mode } j0-value or flag j0 peer

      The overhead byte J0 is configured for the interface.

    • Run flag j1 64byte-or-null-mode [ j1-value ] or flag j1 { 16byte-mode | 1byte-mode } j1-value or flag j1 peer

      The overhead byte J1 is configured for the interface.

    • Run flag c2 c2-value

      The overhead byte C2 is configured for the interface.

  4. Run commit

    The configuration is committed.

Configuring the Frame Format for a POS Interface

The frame format of a POS interface determines the application mode of the interface. POS interfaces support two frame formats: SDH and SONET.

Context

A POS interface supports the following types of frame formats:

  • SDH

  • SONET

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run interface pos interface-number

    The POS interface view is displayed.

  3. Run frame-format { sdh | sonet }

    A frame format is configured for the POS interface.

    SDH and SONET are two optical transmission standards defined by different organizations. These two standards do not have obvious differences in contents and specifications. The selection of SDH or SONET is determined by carriers in different geographical locations and by different device manufacturers. The frame format configured on the POS interface must be the same as that on transmission devices.

  4. Run commit

    The configuration is committed.

Configuring the Scrambling Function for a POS Interface

POS interfaces support the scrambling function for the payload data to avoid excessive consecutive 1s or 0s, which helps the receiver extract line clock signals.

Context

The scrambling function must be enabled on both of the directly connected interfaces.

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run interface pos interface-number

    The POS interface view is displayed.

  3. Run scramble

    The scrambling function of the payload is enabled for the POS interface.

  4. Run commit

    The configuration is committed.

Configuring the Length of the CRC Code for a POS Interface

POS interfaces support a 16- or 32-bit CRC code.

Context

CRC uses an algorithm to verify data consistency on the POS interfaces connecting two devices. The lengths of the CRC codes configured for POS interfaces connecting two devices must be identical.

Perform the following steps on the Routers:

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run interface pos interface-number

    The POS interface view is displayed.

  3. Run crc { 16 | 32 }

    The length of the CRC code is configured for the POS interface.

    The lengths of the CRC codes configured for POS interfaces connecting two devices must be identical. If the lengths of the CRC codes configured for POS interfaces connecting two devices are different, a large number of CRC error packets will be generated.

    CRC uses a high-precision algorithm to verify data consistency on the POS interfaces connecting two devices. CRC using a 32-bit CRC code is more precise than that using a 16-bit CRC code but consumes more resources.

  4. Run commit

    The configuration is committed.

Configuring the MTU for a POS Interface

The MTU is used to reassemble or fragment packets on a POS interface when packets are received or sent on the interface through the IP network protocol.

Context

A Router reassembles or fragments the received or sent packets based on the MTU.

The IP layer limits the length of each frame in a packet to be sent each time. Any time the IP layer receives an IP packet to be sent, it determines to which interface the packet should be delivered and obtains the MTU of the target interface. Then, the IP layer compares the MTU with the packet length. If the packet length is longer than the MTU, the IP layer fragments the packet. Each fragment is not longer than the MTU.

NOTE:
  • If the MTU is set too small and the size of packets is quite large, packets will be divided into too many fragments and be discarded by QoS queues.
  • If the MTU is set too large, packet transmission will be slowed down.

After changing the MTU of an interface by running the mtu mtu command, restart the interface to validate the configuration by running the shutdown and then undo shutdown commands.

Perform the following steps on the Routers:

Procedure

  • Configure the IPv4 MTU.
    1. Run system-view

      The system view is displayed.

    2. Run interface pos interface-number

      The POS interface view is displayed.

    3. Run mtu mtu

      The IPv4 MTU is configured for the POS interface. The MTU is expressed in bytes. The default MTU is 4470.

    4. Run commit

      The configuration is committed.

  • Configure the IPv6 MTU.
    1. Run system-view

      The system view is displayed.

    2. Run interface pos interface-number

      The POS interface view is displayed.

    3. Run ipv6 mtu mtu

      The IPv6 MTU is configured for the POS interface.

      After configuring the IPv6 MTU, run the ppp mru-negotiate { ipv4 | ipv6 } command to start negotiation of the IPv6 MTU.

    4. Run commit

      The configuration is committed.

Configuring the Loopback Function for a POS Interface

Loopback is enabled on an interface only when some special function tests need to be carried out.

Context

If local loopback has been enabled on an interface, the physical status of the interface changes to Up, whereas the link layer protocol of the interface remains Down.

If remote loopback has been enabled on an interface and PPP is used as the link layer protocol, the physical status of the interface changes to Up, whereas the link layer protocol of the interface remains Down. If HDLC is used as the link layer protocol, both the physical status and the link layer protocol status of the interface are Up.

Local loopback and remote loopback cannot be both enabled on a POS interface.

NOTE:

The loopback configurations on a POS interface are different for different LPUs. In the actual configuration, note the following points:

  • To enable local loopback on a POS interface, ensure that the clock of the POS interface works in master mode.
  • To enable remote loopback on a POS interface, ensure that the clock of the POS interface works in slave mode.

Perform the following steps on the Routers:

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run interface pos interface-number

    The POS interface view is displayed.

  3. Run loopback { local | remote }

    The loopback function is configured for the POS interface.

  4. Run commit

    The configuration is committed.

Switching the Working Rate of a POS Subcard

You can run the speed (POS interface view) command to change the working rate of a POS subcard to 155Mbit/s or 622Mbit/s.

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run interface pos interface-number

    The POS interface view is displayed.

  3. Run speed { 155 | 622 }

    Change the working rate of a POS subcard to 155Mbit/s or 622Mbit/s.

  4. Run commit

    The configuration is committed.

Verifying the POS Interface Configuration

After configuring a POS interface, verify the configuration.

Prerequisites

A POS interface has been configured.

Procedure

  • Run the display interface pos [ interface-number ] [ | { begin | exclude | include } regular-expression ] command to check the configuration and status of the POS interface.
  • Run the display interface brief [ | { begin | include | exclude } regular-expression ] command to check brief information about the POS interface.

Example

Run the display interface brief [ | { begin | include | exclude } regular-expression ] command to view brief information about POS interfaces, including the physical status, link layer protocol status, bandwidth utilization, and number of error packets. The display of the command is as follows:

<HUAWEI> display interface brief | include Pos
*down: administratively down
^down: standby
(l): loopback
(s): spoofing
(b): BFD down
(d): DampeningSuppressed
InUti/OutUti: input utility/output utility
Interface                   PHY      Protocol InUti OutUti  inErrors  outErrors
Pos0/1/0                    down     down           0%     0% 831745956          0 
Pos0/1/1                    up       up          0.01%  0.01%3795064053          0 
Pos0/1/2                    down     down           0%     0% 343911292          0 
Pos0/1/3                    down     down           0%     0% 343913408          0 
Pos0/1/4                    down     down           0%     0% 343915353          0 
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Updated: 2019-01-02

Document ID: EDOC1100058399

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