[c-nsp] ME3600 : BFD for BGP running on EVC interface in an VRF

Amos Thong amosthy at hotmail.com
Thu Feb 4 10:58:40 EST 2016

Hi Cisco-NSP Member ?

Have anyone in the forum ever put an SVI/EVC interface in a VRF and do BGP with BFD ?

We made everything work except BFD.  Cisco document at http://products.mcisco.com/c/en/us/products/collateral/switches/me-3800x-series-carrier-ethernet-switch-routers/product_bulletin_c25-683297.html indicates it support BFD on SVI but did no mentioned if it works in a VRF.

Our config is as follow, everything seems right but BFD just wont come up.

Some advise would be appreciated. Thanks.



Interface facing Partner.
platform bfd allow-svi
interface GigabitEthernet0/1
 switchport trunk allowed vlan none
 switchport mode trunk
 mtu 9178
 no cdp enable
 hold-queue 2000 in
  service instance 1 ethernet
  encapsulation dot1q 2501
  rewrite ingress tag pop 1 symmetric
  bridge-domain 2501
vlan 2501

Terminating directly into VRF
interface Vlan2501
 ip vrf forwarding VRF-VOIP                <<<<<<<<<
 mtu 9178
 bandwidth 1000000000
 ip address 211.25.x.x
 no ip redirects
 no ip unreachables
 no ip proxy-arp
 bfd interval 250 min_rx 250 multiplier 3      <<<<<< Enable BFD.
 hold-queue 2000 in

The following config will make the router to be advertised as a VPNv4 route to be advertised to
the RR.
router bgp 1234
  address-family ipv4 vrf VRF-VOIP
  network 211.25.z.z mask
ip route vrf VRF-VOIP 211.25.z.z Null 0

BGP config with Partner
router bgp 1234
 address-family ipv4 vrf VRF-VOIP
  neighbor 211.25.y.y description eBGP Session with telecom (AS4321)
  neighbor 211.25.y.y inherit peer-session voip-nni-telecom
  neighbor 211.25.y.y advertisement-interval 0        <<<<< Configured but not displayed, 0 is the def.
  neighbor 211.25.y.y fall-over bfd single-hop
  neighbor 211.25.y.y activate
  no auto-summary
  no synchronization

template peer-session voip-nni-telecom
  description eBGP Session with telecom
  remote-as 4321
  version 4
  timers 7 21

Verification : Show BGP neighbour status in VRF
vi-01-siteA#show bgp vrf VRF-VOIP all summary
For address family: IPv4 Unicast
<<<<<<Snippe output>>>>>>>>>>>>>>>>
Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
211.25.y.y   4         4321   16558   16992 28744203    0    0 5d09h           2           <<<<< BGP session in VRF is good and exchanging routes

Verfication : BFD function is down.
vi-01-siteA#show bfd nei
IPv4 Sessions
NeighAddr                              LD/RD         RH/RS     State     Int
211.25.y.y                           5/0          Down      Down      Vl2501        <<<<< BFD just wont come up !!!

vi-01-siteA#show bfd neighbors details

IPv4 Sessions
NeighAddr                              LD/RD         RH/RS     State     Int
211.25.y.y                           5/0          Down      Down      Vl2501
Session Host: Software
OurAddr: 211.25.x.x
Handle: 2
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3
Received MinRxInt: 0, Received Multiplier: 0
Holddown (hits): 0(0), Hello (hits): 1000(598)
Rx Count: 0, Rx Interval (ms) min/max/avg: 0/0/0 last: -1 ms ago
Tx Count: 598, Tx Interval (ms) min/max/avg: 760/1000/883 last: 12 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: BGP CEF
Last packet: Version: 1                  - Diagnostic: 0
             State bit: AdminDown        - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 0               - Length: 0
             My Discr.: 0                - Your Discr.: 0
             Min tx interval: 0          - Min rx interval: 0
             Min Echo interval: 0
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