Hi, I've enabled bfd on an iBGP session between two routers. The routers are directly connected, just L2. Taking down the iBGP session (in this case, rebooting the router) results in the following which I find a bit confusing: # birdc show proto BIRD 2.0.3 ready. Name Proto Table State Since Info bfd_ibgp_v4 BFD --- up 2019-02-11 ibgp_v4 BGP --- start 20:59:33.284 Connect Received: Administrative shutdown Why is bfd still in "up" state? Configuration from one of the routers: protocol bfd bfd_ibgp_v4 { interface "igb2" { multiplier 3; interval 500 ms; idle tx interval 1000 ms; }; neighbor X.X.1.6 dev "igb2"; } protocol bgp ibgp_v4 { local X.X.1.5 as 11111; neighbor X.X.1.6 as 11111; bfd on; ipv4 { import all; export all; next hop self; }; } -- Joel
Hi Joel, On 12.02.19 21:08, Joel Dahl wrote:
Hi,
I've enabled bfd on an iBGP session between two routers. The routers are directly connected, just L2.
Taking down the iBGP session (in this case, rebooting the router) results in the following which I find a bit confusing:
# birdc show proto BIRD 2.0.3 ready. Name Proto Table State Since Info bfd_ibgp_v4 BFD --- up 2019-02-11 ibgp_v4 BGP --- start 20:59:33.284 Connect Received: Administrative shutdown
Why is bfd still in "up" state?
Configuration from one of the routers:
protocol bfd bfd_ibgp_v4 { interface "igb2" { multiplier 3; interval 500 ms; idle tx interval 1000 ms; }; neighbor X.X.1.6 dev "igb2"; }
protocol bgp ibgp_v4 { local X.X.1.5 as 11111; neighbor X.X.1.6 as 11111; bfd on; ipv4 { import all; export all; next hop self; }; }
I think because the proto bfd is independent from dynamic routing protocols, because you need at minimum the config stanza for bfd and then enable the usage of bfd for bgp or ospf anyway to make use of it; for reason you could have only running bfd on its own (but I don't know for what benefit). In case of keepalived you could have booth, vrrp and bfd. Best, Bernd
On Wed, Feb 13, 2019 at 02:31:41PM +0100, Bernd Naumann wrote:
Hi Joel,
On 12.02.19 21:08, Joel Dahl wrote:
Hi,
I've enabled bfd on an iBGP session between two routers. The routers are directly connected, just L2.
Taking down the iBGP session (in this case, rebooting the router) results in the following which I find a bit confusing:
# birdc show proto BIRD 2.0.3 ready. Name Proto Table State Since Info bfd_ibgp_v4 BFD --- up 2019-02-11 ibgp_v4 BGP --- start 20:59:33.284 Connect Received: Administrative shutdown
Why is bfd still in "up" state?
Configuration from one of the routers:
protocol bfd bfd_ibgp_v4 { interface "igb2" { multiplier 3; interval 500 ms; idle tx interval 1000 ms; }; neighbor X.X.1.6 dev "igb2"; }
protocol bgp ibgp_v4 { local X.X.1.5 as 11111; neighbor X.X.1.6 as 11111; bfd on; ipv4 { import all; export all; next hop self; }; }
I think because the proto bfd is independent from dynamic routing protocols, because you need at minimum the config stanza for bfd and then enable the usage of bfd for bgp or ospf anyway to make use of it; for reason you could have only running bfd on its own (but I don't know for what benefit).
In case of keepalived you could have booth, vrrp and bfd.
So the bfd state being "up" has nothing to do with the actual session with the neighbor being up or down? -- Joel
Hi Joel, On Wed, Feb 13, 2019 at 08:41:54PM +0100, Joel Dahl wrote:
On Wed, Feb 13, 2019 at 02:31:41PM +0100, Bernd Naumann wrote:
Hi Joel,
On 12.02.19 21:08, Joel Dahl wrote:
Hi,
I've enabled bfd on an iBGP session between two routers. The routers are directly connected, just L2.
Taking down the iBGP session (in this case, rebooting the router) results in the following which I find a bit confusing:
# birdc show proto BIRD 2.0.3 ready. Name Proto Table State Since Info bfd_ibgp_v4 BFD --- up 2019-02-11
[...] This indicates that the BFP Protocol is up not more as i know.
So the bfd state being "up" has nothing to do with the actual session with the neighbor being up or down?
If you want see the different neighbor states use: sh bfd sessions ... 172.XXX.XXX.45 eth0 Down 2018-12-08 1.000 0.000 172.XXX.XXX.15 eth0 Up 2018-12-01 0.100 0.500 172.XXX.XXX.6 eth0 Up 2018-12-16 0.100 0.500 ... This should indicate the different neighbors. HTH, tim -- Tim Weippert http://weiti.org - weiti@weiti.org GPG Fingerprint - E704 7303 6FF0 8393 ADB1 398E 67F2 94AE 5995 7DD8
participants (3)
-
Bernd Naumann -
Joel Dahl -
Tim Weippert