I think you've accurately described the situation. After setting static routes and disabling the underlay I see the following
root@test> show bgp summary
Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
10.92.101.194 64830 13 13 0 3 1 Active
root@test> show bgp summary
Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
10.92.101.194 64830 13 13 0 3 2 Active
. . .
root@test> show bgp summary
Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
10.92.101.194 64830 13 13 0 3 29 Active
root@test> show bgp summary
Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
10.92.101.194 64830 13 13 0 3 30 Active
root@test> show bgp summary
Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
10.92.101.194 64830 13 13 0 3 31 Active
root@test> show bgp summary
Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
10.92.101.194 64830 1 1 0 3 0 Establ
Original Message:
Sent: 11-17-2020 22:09
From: BEN DALE
Subject: EVPN VXLAN Overlay Peering
Hi Paul,
During the 30-second window, can you grab the output of show bgp summary
and see what state the OVERLAY group session is in?
It sounds a bit like the OVERLAY group session might be failing to connect initially (neighbour address may not yet be reachable), then having to wait for a full session timeout before trying again. You could prove this by configuring static routes from [L1]->[S1]->[L2 Peering Address] and [L2]->[S1]->[L1 Peering Address] and seeing if the session comes up faster.
------------------------------
Cheers,
Ben Dale
JNCIE-SEC #63
JNCIP-SP
JNCIP-ENT
JNCIP-DC
Original Message:
Sent: 11-15-2020 02:15
From: Unknown User
Subject: EVPN VXLAN Overlay Peering
Greetings-
I have a simple two-leaf evpn-vxlan setup with a single esi-lag configured. When rebooting one of the leafs (or disabling and reenabling all interfaces) I'm seeing the leaf-to-leaf overlay bgp neighborship sit in active state and take up to 30 seconds to peer even though the underlay has fully established (which is very quick) and I have layer 3 connectivity between the two leafs. There appears to be some sort of rolling 30-second holddown that the ibgp peering is experiencing that the underlay ebgp is not, with the result being a 1-30 second delay. I've tried playing with hold-down settings but don't see any change in behavior. The issue is that the esi-lag interface comes up before peering has established, resulting in traffic from the host being blackholed. I've set a 60-second hold-time up on the lag interfaces, which allows enough time for peering to catch up, but I'd like to know if there is a way to peer quickly once layer 3 is established between the leafs.
group OVERLAY {
type internal;
local-address 10.92.101.194;
family evpn {
signaling;
}
local-as 64830;
multipath;
bfd-liveness-detection {
minimum-interval 1000;
multiplier 3;
session-mode automatic;
}
neighbor 10.92.101.195;
}
-Paul