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Configuration Guide - IP Unicast Routing

S7700 and S9700 V200R010C00

This document describes IP Unicast Routing configurations supported by the switch, including the principle and configuration procedures of IP Routing Overview, Static Route, RIP, RIPng, OSPF, OSPFv3, IS-IS(IPv4), IS-IS(IPv6), BGP, Routing Policy ,and PBR, and provides configuration examples.
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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).
Displaying and Maintaining FIB Tables

Displaying and Maintaining FIB Tables

Context

NOTE:

Unless otherwise stated, FIB tables in this document refer to unicast FIB tables.

A device selects routes according to its IP routing table and forwards packets according to FIB tables. If the number of entries in a FIB table reaches or exceeds the limit, that is, the FIB table is overloaded, new active routes cannot be delivered to the FIB table, affecting packet forwarding.

You can increase the FIB table size or use the following methods to solve this problem.
  • Configure a FIB policy for LPUs to filter unnecessary FIB entries and reduce the FIB entries delivered to LPUs.
  • Configure the resource allocation mode of the LPU extended entry register to adjust the IPv4 FIB table size and IPv6 FIB table size on LPUs.
When the FIB table of an LPU is overloaded, the device deals with this problem in either of the following ways:
  • Overload forwarding: The device uses existing FIB entries to forward packets and does not deliver new active routes to this FIB table.

  • Overload suspension: The device shuts down all the physical interfaces on this LPU.

When the FIB table of an LPU is overloaded, this LPU enters the overload forwarding state and must be manually restored to the normal state.

Procedure

  • Check FIB entries.

    NOTE:
    • If no slot ID is specified, you can check FIB entries of an MPU.
    • If a slot ID is specified, you can check FIB entries of the LPU in this specified slot.
    • Run the display fib [ slot-id ] [ vpn-instance vpn-instance-name ] [ verbose ] command to check IPv4 FIB entries.
    • Run the display fib [ vpn-instance vpn-instance-name ] acl acl-number [ verbose ] command to check IPv4 FIB entries that match a specified ACL.
    • Run the display fib [ vpn-instance vpn-instance-name ] ip-prefix prefix-name [ verbose ] command to check IPv4 FIB entries that match a specified IP prefix list.
    • Run the display fib [ slot-id ] [ vpn-instance vpn-instance-name ] destination-address1 [ verbose ] command to check IPv4 FIB entries that match a specified destination IP address.
    • Run the display fib [ slot-id ] [ vpn-instance vpn-instance-name ] destination-address1 destination-mask1 [ verbose ] command to check IPv4 FIB entries that exactly match a specified destination IP address and mask.
    • Run the display fib [ slot-id ] [ vpn-instance vpn-instance-name ] destination-address1 longer [ verbose ] command to check all IPv4 FIB entries that match destination IP addresses in the natural mask range.
    • Run the display fib [ slot-id ] [ vpn-instance vpn-instance-name ] destination-address1 destination-mask1 longer [ verbose ] command to check all IPv4 FIB entries that match destination IP addresses in a specified mask range.
    • Run the display fib [ slot-id ] [ vpn-instance vpn-instance-name ] destination-address1 destination-mask1 destination-address2 destination-mask2 [ verbose ] command to check IPv4 FIB entries that match destination IP addresses in the range of destination-address1 destination-mask1 and destination-address2 destination-mask2.
    • Run the display fib [ vpn-instance vpn-instance-name ] next-hop ip-address command to check IPv4 FIB entries that match a specified next-hop IP address.
    • Run the display fib [ slot-id ] [ vpn-instance vpn-instance-name ] statistics command to check the total number of IPv4 FIB entries.
    • Run the display fib [ slot-id ] statistics all command to check IPv4 FIB entry statistics.
    • Run the display ipv6 fib [ slot-id ] [ vpn-instance vpn-instance-name ] [ verbose ] command to check IPv6 FIB entries.
    • Run the display ipv6 fib [ slot-id ] [ vpn-instance vpn-instance-name ] ipv6-address [ verbose ] command to check IPv6 FIB entries that match a specified destination IPv6 address.
    • Run the display ipv6 fib [ slot-id ] [ vpn-instance vpn-instance-name ] ipv6-address prefix-length [ verbose ] command to check IPv6 FIB entries that exactly match a specified destination IPv6 address and mask.
    • Run the display ipv6 fib [ slot-id ] [ vpn-instance vpn-instance-name ] statistics command to check the total number of IPv6 FIB entries.
    • Run the display ipv6 fib [ slot-id ] statistics all command to check IPv6 FIB entry statistics.

  • Maintain FIB tables.

    • Enable the alarm function for the IPv4 route prefix usage and set the alarm threshold.
      1. Run:

        system-view

        The system view is displayed.

      2. Run:

        fib threshold-alarm upper-limit upper-limit-value lower-limit lower-limit-value

        The alarm function for the IPv4 route prefix usage is enabled and the alarm threshold is set.

        By default, the alarm function for IPv4 route prefix usage is enabled. The upper alarm threshold is 85% and the lower alarm threshold is 75%.

        NOTE:

        X series cards do not support the alarm function for the IPv4 route prefix usage.

    • Configure an IPv4 FIB policy on a specified LPU.

      1. (Optional) Run:

        display fib-policy slot slot-id

        The IPv4 FIB policy configuration of a specified LPU is displayed.

      2. Run:

        system-view

        The system view is displayed.

      3. Run:

        apply fib-policy { no-route | public | vpn-instance vpn-instance-name &<1-6> } slot slot-id

        An IPv4 FIB policy is configured on a specified LPU.

        By default, an LPU does not have an IPv4 FIB policy configured and receives all IPv4 FIB entries delivered by an MPU.

      4. Run:

        refresh fib slot slot-id

        The IPv4 FIB table of a specified LPU is refreshed.

    • Configure an IPv6 FIB policy on a specified LPU.
      1. (Optional) Run:

        display ipv6 fib-policy slot slot-id

        The IPv6 FIB policy configuration of a specified LPU is displayed.

      2. Run:

        system-view

        The system view is displayed.

      3. Run:

        apply ipv6 fib-policy { no-route | public | vpn-instance vpn-instance-name &<1-6> } slot slot-id

        An IPv6 FIB policy is configured on a specified LPU.

        By default, an LPU does not have an IPv6 FIB policy configured and receives all IPv6 FIB entries delivered by an MPU.

      4. Run:

        refresh ipv6 fib slot slot-id

        The IPv6 FIB table of a specified LPU is refreshed.

    • Restore a specified LPU that uses an overloaded IPv4 FIB table from the overload forwarding state to the normal state.
      1. (Optional) Run:

        display fib overload state slot slot-id

        The current status and overload processing mode of a specified LPU that uses an overloaded IPv4 FIB table are displayed.

      2. Run:

        system-view

        The system view is displayed.

      3. Run:

        recover fib overload forward slot slot-id

        The specified LPU that uses an overloaded IPv4 FIB table is restored from the overload forwarding state to the normal state.

      4. Run:

        refresh fib slot slot-id

        The IPv4 FIB table of a specified LPU is refreshed.

    • Restore a specified LPU that uses an overloaded IPv6 FIB table from the overload forwarding state to the normal state.
      1. (Optional) Run:

        display ipv6 fib overload state slot slot-id

        The current status and overload processing mode of a specified LPU that uses an overloaded IPv6 FIB table are displayed.

      2. Run:

        system-view

        The system view is displayed.

      3. Run:

        recover ipv6 fib overload forward slot slot-id

        The specified LPU that uses an overloaded IPv6 FIB table is restored from the overload forwarding state to the normal state.

      4. Run:

        refresh ipv6 fib slot slot-id

        The IPv6 FIB table of a specified LPU is refreshed.

    • Configure the resource allocation mode of the LPU extended entry register to adjust the IPv4 FIB table size and IPv6 FIB table size on an LPU.

      After configuring the resource allocation mode of the LPU extended entry register, save the configuration and restart the LPU to make the configuration take effect. Restarting the LPU will interrupt services on the LPU. Therefore, confirm the action when you restart the LPU.

      1. (Optional) Run:

        display resource-assign configuration

        The configuration of the extended entry space resource of all LPUs is displayed.

      2. (Optional) Run:

        display resource-assign configuration slot slot-id

        The configuration of the extended entry space resource of a specified LPU is displayed.

      3. Run:

        system-view

        The system view is displayed.

      4. Run:

        assign resource-mode mode-id slot slot-id

        The resource allocation mode of the extended entry register of a specified LPU is configured.

        By default, see the following specification list for default specifications of different LPU series.

        NOTE:
        • For different LPUs' support for this command, see the following specification list.

        • After setting the resource mode for extended entry register space of an LPU, save the configuration and reset the LPU for the configuration to take effect.

        • For an X2E or X2H series LPU, set the acl mode to dual-ipv4-ipv6 before configuring this command.
        • In enhanced-ipv4 or ipv4-ipv6 resource mode, EH1D2X48SEC0 LPUs do not support redirection to low-priority next hops.
        • In enhanced-arp resource mode, EH1D2X48SEC0 LPUs do not support MPLS.

        • In 128k-arp resource mode, EE series LPUs do not support MPLS.

    • Configure periodic refresh of FIB entries.
      1. Run:

        system-view

        The system view is displayed.

      2. Run:

        undo fib regularly-refresh disable

        Periodic refresh of FIB entries is enabled.

        By default, periodic refresh of FIB entries is enabled.

      3. You can run either of the following commands according to the actual requirements.

        • Run:

          fib regularly-refresh  { interval interval [ entry-number entry-number ] | entry-number entry-number }

          The interval for refreshing FIB entries and the number of FIB entries refreshed at an interval are configured.

          By default, the interval for refreshing FIB entries is 1 second and the number of FIB entries refreshed at an interval is 100.

        • Run:

          fib regularly-refresh start-time start-time

          The time when FIB entries are refreshed is configured.

          By default, FIB entries are refreshed at 01:00 a.m.

    • Configure periodic refresh of IPv6 FIB entries.
      1. Run:

        system-view

        The system view is displayed.

      2. Run:

        undo ipv6 fib regularly-refresh disable

        Periodic refresh of IPv6 FIB entries is enabled.

      3. You can run either of the following commands according to service requirements.

        • Run:

          ipv6 fib regularly-refresh interval interval

          The interval for refreshing IPv6 FIB entries is configured.

          By default, the interval for refreshing IPv6 FIB entries is 1 second.

        • Run:

          ipv6 fib regularly-refresh entry-number entry-number

          The number of IPv6 FIB entries refreshed at an interval is configured.

          By default, the number of IPv6 FIB entries refreshed at an interval is 100.

        • Run:

          ipv6 fib regularly-refresh start-time start-time

          The time when IPv6 FIB entries are refreshed is configured.

          By default, FIB entries are refreshed at 00:00 a.m.

Example

Run the display fib statistics all command to check the total number of IPv4 FIB entries on an MPU and the total number of all IPv4 FIB entries.

<HUAWEI> display fib statistics all
IPv4 FIB Total Route Prefix Count : 16388; Entry Count : 16388

IPv4 FIB Public Route Prefix Count : 16388; Entry Count : 16388
IPv4 FIB VPN-instance VPNA Route Prefix Count : 0; Entry Count : 0
IPv4 FIB VPN-instance VPNB Route Prefix Count : 0; Entry Count : 0

Run the display fib slot-id statistics all command to check the IPv4 FIB route prefix capacity of a specified LPU.

<HUAWEI> display fib 1 statistics all
IPv4 FIB Route Prefix Capacity : 16384
IPv4 FIB Total Route Prefix Count : 16384; Entry Count : 16384

IPv4 FIB Public Route Prefix Count : 16384; Entry Count : 16384
IPv4 FIB VPN-instance VPNA Route Prefix Count : 0; Entry Count : 0
IPv4 FIB VPN-instance VPNB Route Prefix Count : 0; Entry Count : 0

Run the display fib overload state command to check the overload state of a specified LPU. The command output shows that the LPU is in overload forwarding state.

<HUAWEI> display fib overload state slot 1
  Overload mode:
    Overload forward mode.
  Overload state:
    Overload forward state.
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Updated: 2019-08-21

Document ID: EDOC1000141900

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