04-02-2003 11:18 AM - edited 03-02-2019 06:20 AM
How do Frame-Relay Keepalives affect routing tables when using
static routes that point to a Next-Hop-Address versus using static
routes that point to the local serial (sub)interface ? I know that if
you point to the local interface versus a next-hop-address and the
frame link causes a change in the serial interface's status that the
routes are dropped from the routing table much quicker than they
would be dropped from the routing table if the static route pointed
to the next-hop-address. Please advise.
04-03-2003 11:26 AM
LMI is the protocol between the router's FR interface and the carrier's FR edge switch. If you disable keepalives on the FR interface, you're turning off LMI. This is a bad idea, since LMI keepalive packets let the router know when PVC's are up or not (see status on every 6th LMI update). Without LMI the router would never flag a PVC as down.
Regards,
Rob Bristow
CCIE #3335
04-03-2003 12:14 PM
Rob,
Are LMI keepalives enabled by default on a cisco router ? I've never manually
disabled it and I was given the following configuration statements by a customer
of our's. I'm curious... If the following statements aren't in a router's configuration,
does that mean LMI isn't enabled for a given interface ?
Global Config Mode:
map-class frame-relay keepalive
frame-relay end-to-end keepalive mode bidirectional
(Sub)Interface Mode:
frame-relay class keepalive
Please advise.
Thanks,
Mike
04-08-2003 03:20 PM
Hi Mike,
The lmi keepalives are enabled by default on the interface, regardless of whether or not yo have the map-class. You can tell this by looking at the output of show frame-relay lmi. You'll see the lmi status frames being sent and recieved.
The map-class allows you to monitor/manage each pvc per sub-interface, by sending keepalives back and forth between pvc end points.
Hope that helps
Parvez
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