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How to verify communities since and from peers?

Hello folks, I have this typical scenario:

               |CE1|-----------|PE1|-----------|P|----------|PE2|-----------|CE2|

           1.1.1.1/32       2.2.2.2/32     3.3.3.3/32 4.4.4.4/32     5.5.5.5/32

                                                                                       Lo0 10.34.154.90

The PE-CE protocol of choice is BGP, and the customer wants to add whatever community to prefixes as they want without the intervention of the provider. I setup the send-community both VPNv4 statement in the PE routers, but I have not found a good command can help me verify the community added by CEs to prefixes.

Using the command in PE2:

show ip bgp vpnv4 all <prefix> , show the regular community using by the RT, but not the added by the CE with additive statement.

PE1#sh ip bgp vpnv4 all 10.34.154.90

BGP routing table entry for 22364:21300:10.34.154.90/32, version 44605017

Paths: (1 available, best #1, table VRF1)

Advertised to update-groups:

     1         2         596

64852

   CE2 from CE2 (10.43.255.255)

     Origin incomplete, metric 0, localpref 100, valid, external, best

     Community: 200 14549214

     Extended Community: RT:22364:21300

     mpls labels in/out 918/nolabel

What command can show me the total of the extend communities?

Also how can I change the peer: 10.25.234.14 (CE2) from the point of view of this command to P peer?

Thanks in advanced

  • MPLS
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Re: How to verify communities since and from peers?

Hello Mbonilla,

PE-CE protocol is EBGP but it is a standard session so the CE can only add standard BGP communities

Community: 200 14549214

     Extended Community: RT:22364:21300

the second line refers to RT extended community the first line refers to standard community.

It is likely that the community was set by CE router I see that the value is expressed in the default format.

In order to see more readable community ( like ASN:value)  values you need the command

config t

ip bgp-community new-format

see

http://www.cisco.com/en/US/docs/ios-xml/ios/iproute_bgp/command/bgp-c1.html#GUID-D2961543-7CC3-4AB0-8CD7-4DC0B47F32E1

after this the router will show communities values like 65000:2345, instead of a 32 bit unsigned integer that we poor human beings cannot understand!

Hope to help

Giuseppe

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