[j-nsp] BFD issue on OSFP between ASR9001 and MX80

[Terry Jones]

Hello all, hoping for some info.  I am seeing an issue with BFD between an
MX80 and a Cisco ASR9001. Long story short is I am seeing a bfd issue caused
by adaptive mode on the Juniper. 

Setup is    ASR<--o-->EX4200<--o-->EX4500<--o-->MX80
                       |                       |vc|
|vc|             
                    ASR<--o-->EX4200<--o-->EX4500<--o-->MX80


On the MX80, I have an interface configured in a logical-system with a link
that has an ospf session through the EX4200 & EX4500 to the ASR. In the
logical-system I have a bridge-domain between the two MX80's that use an irb
using vrrp. I have route-tracking on a route that is north of the ASR.

Problem is that when I configure a bfd session to 3x100ms and fail the ASR
link, the ospf is dropped & vrrp cuts over within a sub-second time (900ms)
the first time only as it should. When I fail it a second (or more) times,
it fails at the default BFD time of 3 multipler x3 interval time (9 secs).
The first output below shows the BFD session in a down state with these
defaults. It defaults to 3.0 transmit interval with a multiplier of 3,so a
detect time of 9sec. When it comes back up, the transmit interval cuts back
to 100ms, but the next time that I fail the link, bfd actually doesn't
conform to the 100ms time that is shows, but rather it waits for 9 seconds.
This can be overcome by running the 'clear bfd adaptation' command. I tried
the no-adaption knob on the bfd-liveliness-detection and it doesn't appear
to work. Only clearing the bfd adaptation seems to fix the issue. I've tried
changing the bfd-liveness-detection parameters, but not sure if I'm making
an error or what. The commands are below. Any ideas?

I am running 13.3R1.6 on the MX80.

set groups OSPF_DEFAULTS logical-systems <*> protocols ospf area <*>
interface "<[axg]e*>" bfd-liveness-detection version automatic
set groups OSPF_DEFAULTS logical-systems <*> protocols ospf area <*>
interface "<[axg]e*>" bfd-liveness-detection minimum-interval 100
set groups OSPF_DEFAULTS logical-systems <*> protocols ospf area <*>
interface "<[axg]e*>" bfd-liveness-detection minimum-receive-interval 100
set groups OSPF_DEFAULTS logical-systems <*> protocols ospf area <*>
interface "<[axg]e*>" bfd-liveness-detection multiplier 3
set groups OSPF_DEFAULTS logical-systems <*> protocols ospf area <*>
interface "<[axg]e*>" bfd-liveness-detection no-adaptation
set groups OSPF_DEFAULTS logical-systems <*> protocols ospf area <*>
interface "<[axg]e*>" bfd-liveness-detection detection-time threshold 500

 
Detect   Transmit
Address                  State     Interface      Time     Interval
Multiplier
172.28.242.253           Up        ae2.0          9.000     3.000        3
 Client OSPF realm ospf-v2 Area 0.0.0.0, TX interval 0.100, RX interval
0.100
 Session up time 00:00:03
 Local diagnostic None, remote diagnostic None
 Remote state Up, version 1
 Logical system 1, routing table index 10
 Session type: Single hop BFD
 Min async interval 0.100, min slow interval 3.000
 Adaptive async TX interval 3.000, RX interval 3.000
 Local min TX interval 3.000, minimum RX interval 0.100, multiplier 3
 Remote min TX interval 0.100, min RX interval 0.100, multiplier 3
 Threshold for detection time 0.500
 Local discriminator 115, remote discriminator 2148073574
 Echo mode disabled/inactive
 Remote is control-plane independent
 Adaptation disabled
  Session ID: 0x80017

1 sessions, 1 clients

 
Detect   Transmit
Address                  State     Interface      Time     Interval
Multiplier
172.28.242.253           Up        ae2.0          0.300     0.100        3
 Client OSPF realm ospf-v2 Area 0.0.0.0, TX interval 0.100, RX interval
0.100
 Session up time 00:00:04
 Local diagnostic None, remote diagnostic None
 Remote state Up, version 1
 Logical system 1, routing table index 10
 Session type: Single hop BFD
 Min async interval 0.100, min slow interval 1.000
 Adaptive async TX interval 0.100, RX interval 0.100
 Local min TX interval 0.100, minimum RX interval 0.100, multiplier 3
 Remote min TX interval 0.100, min RX interval 0.100, multiplier 3
 Threshold for detection time 0.500
 Local discriminator 115, remote discriminator 2148073574
 Echo mode disabled/inactiveupdate-adj
 Remote is control-plane independent
 Adaptation disabled
  Session ID: 0x80017

1 sessions, 1 clients
Cumulative transmit rate 10.0 pps, cumulative receive rate 10.0 pps

Thanks,
Terry 
terry.jones at war-eagle.me