POS Links not going down ?

[FilthyMinx]

Hi,

I've had a situation arise recently where some STM-16 POS links were killed due to a fiber cut. While this was happening, I started noticing that some of the routers were making some rather inventive OSPF decisions ( like sending traffic to a router which had only one working interface etc etc. )

Further investigation revealed that a number of the POS links were sitting in an "Up / Up" state, even though there was a physical cut at the optical layer.

The POS interfaces are point to point , GSR to GSR. I tried pinging across them - no response. I then admin'd them down and everything returned to "normal", OSPF picking the correct links etc etc.

Question is, has anyone seen this sort of behaviour before ? We're running HDLC encapsulation on the links - would PPP have handled better ?

Any theorys / help would be greatly appreciated

Thanks,
Allan.

 

[benzito]

Have you tried enabling keepalives on the interfaces? Never seen this and not sure if this would work...just a suggestion. I'm thinking that the router would drop the interface when the hello packet (keepalive) isn't ack'd.