RSVP question

Unanswered Question
Aug 5th, 2008


I have two remote location connected to MPLS cloud .Both are locations have severs those are running heartbeats to check the connectivity can I go for RSVP to reserve some bandwidth for heartbeats .

Incase RSVP is right options what will be the configuration I need to make .

I thought of implementing Priority quque but the outgoing interfaces are gigabit interface and bandwidth is limited from Service provide dont know if priority quque will help in this scenario pls suggest .


I have this problem too.
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4rmorris Tue, 08/05/2008 - 17:00

I would go with priority queuing. RSVP is complicated, and between two routers doesn't make much sense to me. You have control of the interfaces, so you can allocate bandwidth the way you want.

Priority queue always goes first, so you could put traffic in the priority queue and even though you're not doing the rate limiting the heartbeat traffic will still be at the head of the line. If the link is congested it can still be dropped by the SP, so it's not great if you expect congestion. If you configure the "bandwidth" statement correctly on the interface, this should work ok though.

Better option: shape the traffic out of the interface to the speed the service provider guarantees. Then the priority queuing mechanism will provide the configured bandwidth to the heartbeat traffic. We shape our MPLS links because they're provided as sub-interfaces and have no native queuing.

Sample config (for a 1 Mbps service with a 512k priority queue)

policy-map SHAPE

class class-default

shape average 1000000

service-policy PRIORITY


policy-map PRIORITY


priority 512


interface gigabit 0/0

bandwidth 1000

service-policy output SHAPE

The nested policy map PRIORITY handles the queuing, and the parent map SHAPE ensures you don't oversubscribe your bandwidth.

Good luck,



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