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Huawei’s equivalent of Cisco’s ‘logging synchronous’

15 Jan, 2013 FAQ 0

If a router wants you to know something, it wants you to know right now!

Let’s look what will happen if you are entering a long command and the device wants you to be informed about a link’s failure:

[Huawei-acl-adv-3000]rule 10 permit ip vpn-instance vpn_labnario source 1.1.1.1 0.0.0.255 destination 1.1.1.2
Jan 15 2013 11:04:18-08:00 Huawei %%01PHY/1/PHY(l)[5]:    GigabitEthernet0/0/0:
change status to down
Jan 15 2013 11:04:18-08:00 Huawei %%01IFNET/4/LINK_STATE(l)[6]:The line protocol
IP on the interface GigabitEthernet0/0/0 has entered the DOWN state.
^
Error:Incomplete command found at '^' position.

When you click ‘Enter’ you will have to write the command once again. It is frustrating for all network administrators.

Unfortunately we cannot change it, like on Cisco’s devices, by ‘logging synchronous‘ command.

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BGP peering with loopback interfaces

8 Jan, 2013 IP Routing 0

As you know BGP uses TCP to establish connection between two neighbours. That’s why TCP source IP is an IP of outgoing interface. To establish IBGP peering between loopback interfaces, you have to define source IP. On Huawei device, you can define source IP, as loopback interface, by the following command:

peer 150.0.0.1 connect-interface LoopBack 0

This command is applicable in a case when multiple links exist between BGP neighbours. Even if physical interface fails, the device still sends BGP packets.

What about EBGP connection with loopback interfaces?

A directly connected physical link must be available between EBGP peers. You have additional hops when using loopback interfaces. In case of indirect peer relationship please remember to use the following command:

peer 160.0.0.1 ebgp-max-hop 3

Anyway, there is recommended to establish EBGP connection through directly connected physical links.

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how does BGP select routes

27 Dec, 2012 IP Routing 0

When there are multiple routes to the same destination, BGP (Border Getaway Protocol)  on Huawei devices:

  • Prefers the route with the largest PreVal. PrefVal is a Huawei-specific parameter. It is valid only on the device where it is configured.
  • Prefers the route with the highest Local_Pref.
  • Prefers a locally originated route. A locally originated route takes precedence over a route learned from a peer.
  • Prefers the aggregated route. The preference of an aggregated route is higher than a non-aggregated route.
  • Prefers the local route that is manually aggregated. The preference of the local route that is manually aggregated is higher than that of automatically aggregated.
  • Prefers the local route that is imported by using network command. The preference of the route that is imported by using the network command is higher than that imported by  import-route command.
  • Prefers the route with the shortest AS_Path.
  • Compares Origin attributes, and selects routes whose origin types are IGP, EGP, and Incomplete respectively.
  • Prefers the route with the smallest MED.
  • Prefers the routes learned from EBGP. The preference of an EBGP route is higher than an IBGP.
  • Prefers the route of an IGP with the lawest metric in an AS. If load balancing is configured and there are multiple external routes with the same AS_Path, load balancing is performed according to the number of configured routes.
  • Prefers the route with the shortest Cluster_List.
  • Prefers the route with the smallest Originator_ID.
  • Prefers the route advertised by the router with the smallest router ID.
  • Compares IP addresses of its peers, and prefers the route that is learnt from the peer with the smallest IP address.

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    Multiple Spanning Tree Protocol on Huawei switch

    20 Dec, 2012 Ethernet 0

    The Multiple Spanning Tree Protocol (MSTP) was originally defined as the IEEE 802.1s standard protocol. Now the standard IEEE 802.1Q-2005 includes MSTP. The basic role of this protocol is to prevent L2 loops. I do not want to explain MSTP in details, as this can be easily found on the Internet. I just want to show you:

    • how to configure this protocol using Huawei CLI
    • how to load balance traffic over redundant links.

    Let’s assume that we have the following physical topology:

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