3

I have a problem with understanding the neighbor-groups in Cisco IOS XR. I will describe it on below example:

router bgp 10429 
 bfd minimum-interval 300
 !
 neighbor-group IBGP
  remote-as 10429
  address-family ipv4 unicast
   route-policy pass-all in
   route-policy pass-all out
  !
  address-family l2vpn vpls-vpws
   route-policy block-all in
   route-policy block-all out
  !
 !
 neighbor 187.100.0.89
  remote-as 65200
  use neighbor-group IBGP
  description TEST
  address-family ipv4 unicast
 !
!

1. Remote-as will be overwritten by neighbor-group?
2. Does neighbor inherit pass-all in and pass-all out policies because contain 'address-family ipv4 unicast' row?
3. Does neighbor inherit policies, which are under 'address-family l2vpn vpls-vpws'?

In my current understanding:
1. No
2. Yes
3. No, because there is no row 'address-family l2vpn vpls-vpws' under the neighbor.

3

Here are my answers:

  1. No, remote-as value (of neighbor 187.100.0.89) stays unchanged of 65200.
  2. Yes, even you do not have 'address-family ipv4 unicast'.
  3. Yes, the neighbor inherits policies under 'address-family l2vpn vpls-vpws'.

You can verify all the answers by using commands:

#show bgp neighbors 187.100.0.89 configuration    

  neighbor 187.100.0.89
     remote-as 65200             []
     description TEST            []
     address-family IPv4 Unicast []
      policy pass-all in         [n:IBGP]
      policy pass-all out        [n:IBGP]
     address-family L2VPN VPLS   [n:IBGP]
      policy block-all in        [n:IBGP]
      policy block-all out       [n:IBGP]

#show bgp neighbors 187.100.0.89 inheritance

  Session:      n:IBGP
  IPv4 Unicast: n:IBGP
  L2VPN VPLS:   n:IBGP

#show bgp neighbors  187.100.0.89

  BGP neighbor is 187.100.0.89
  Remote AS 65200, local AS 10429, external link
  Description: TEST
  ...
  For Address Family: IPv4 Unicast
  BGP neighbor version 0
  Update group: 0.1 Filter-group: 0.0  No Refresh request being processed
  Route refresh request: received 0, sent 0
  Policy for incoming advertisements is pass-all
  Policy for outgoing advertisements is pass-all
  ...
  For Address Family: L2VPN VPLS
  BGP neighbor version 0
  Update group: 0.1 Filter-group: 0.0  No Refresh request being processed
  Community attribute sent to this neighbor
  Extended community attribute sent to this neighbor
  Route refresh request: received 0, sent 0
  Policy for incoming advertisements is block-all
  Policy for outgoing advertisements is block-all

I hope it is useful and answers your questions. Please check Cisco docs about Template Inheritance Rules for BGP on IOS-XR.

1

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.