Huawei AR1200 can not receive same AS routes from its neighbor peer case

Latest reply: May 21, 2018 02:14:53 352 1 0 0
      Issue Description

The issue is that eBGP session is established but unable to receive any routing in routing table which contains same AS number i.e 65450, Routes with AS 65450 while Advertised from PE & there are 23 items are not visible in CE routing table.


The network topology as follwing:

            147701ea1e954f489811b640c4648505

 

transparent.gif Handling Process

1. Analyzed the information customer feedback, the router on PE include the AS 65450,as following:

Detail of routes from AS 65450 on PE:

 

*> 10.10.101.0/24   172.16.0.2               0             0 65450 i

*>i10.10.109.0/24   221.120.255.79           0    700      0 65450 i

*>i10.10.110.0/24   221.120.255.79           0    700      0 65450 i

*>i10.10.113.0/24   221.120.255.77           0    700      0 65450 i

*>i10.10.114.0/24   221.120.255.77           0    700      0 65450 i

*>i10.10.121.0/24   221.120.255.76           0    700      0 65450 i

*>i10.10.122.0/24   221.120.255.76           0    700      0 65450 i

*>i10.10.123.0/24   221.120.255.67           0    700      0 65450 i

*>i10.10.124.0/24   221.120.255.67           0    700      0 65450 i

*> 10.10.129.0/24   172.16.0.114             0             0 65450 i

*> 10.10.130.0/24   172.16.0.114             0             0 65450 i

*> 10.10.131.0/24   172.16.0.122             0             0 65450 i

*> 10.10.132.0/24   172.16.0.122             0             0 65450 i


2. According to network topology and the route informtion, by default the eBGP peer will not receive the route which include the same AS in the AS-list(same with your situation) , this is used to avoid the route loop. So this is a normal behaviour.


3. But customer said when they change CE device from Huawei to Cisco, Cisco device is able to recerve all routes which PE is advertising. So we suspend Cisco has some special configuration to do this. So we check if huawei device have some command can reach this requirement. after check and test confirm, we find the solution as following:

bgp 65450

peer 172.16.0.121 as-number 17557

#

ipv4-family unicast

  undo synchronization

  network 10.10.131.0 255.255.255.0

  network 10.10.132.0 255.255.255.0

  import-route direct

  peer 172.16.0.121 enable

peer 172.16.0.121 allow-as-loop 2          //need to add this command,  the parameter 2 is the AS in the AS-list times

 

 And notice that if all the CE devices are AR1220, then all the devices need to add the above command.

transparent.gif Root Cause

by default the eBGP peer will not receive the route which include the same AS in the AS-list(same with your situation) , this is used to avoid the route loop. So this is a normal behaviour.Need to add some special command to reach this requirement.

transparent.gif Solution

Need to add some special command to reach this requirement. As following:

bgp 65450

peer 172.16.0.121 as-number 17557

#

ipv4-family unicast

  undo synchronization

  network 10.10.131.0 255.255.255.0

  network 10.10.132.0 255.255.255.0

  import-route direct

  peer 172.16.0.121 enable

peer 172.16.0.121 allow-as-loop 2          //need to add this command,  the parameter 2 is the AS in the AS-list times

From group: Router
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MVE Created May 21, 2018 02:14:53 Helpful(0) Helpful(0)

useful document, thanks
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Telecommunications%20Engineer%2C%20currently%20senior%20project%20manager%20of%20the%20radio%20access%20network%20and%20partner%20of%20Huawei%20de%20Tunisia.

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