Cisco IOS Cookbook, 2nd Edition

Aggregating RSVP Reservations

Problem

You want to aggregate several RSVP reservations so that the core of your network doesn’t need to keep track of them all separately.

Solution

This feature requires the creation of a boundary between the edge region of the network, where RSVP runs normally, and the core of the network where packets are classified purely using DSCP:

Router2#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router2(config)#interface FastEthernet0/0
Router2(config-if)#ip address 192.168.101.1 255.255.255.0
Router2(config-if)#ip rsvp bandwidth 128 56
Router2(config-if)#ip rsvp data-packet classification none
Router2(config-if)#ip rsvp resource-provider none
Router2(config-if)#exit
Router2(config)#interface Serial0/0.1 point-to-point
Router2(config-subif)#ip address 192.168.55.10 255.255.255.252
Router2(config-subif)#frame-relay interface-dlci 409
Router2(config-fr-dlci)#ip rsvp bandwidth 128 56
Router2(config-subif)#ip rsvp data-packet classification none
Router2(config-subif)#ip rsvp resource-provider none
Router2(config-subif)#exit
Router2(config)#end
Router2#

Discussion

The biggest problem with RSVP is that it doesn’t scale well when you have a large number of reservations. This is a good model at the edge of the network, but in the middle of the network, where there could be a huge number of flows to keep track of, it would be preferable to use traditional DSCP-based packet marking and queuing.

However, it is not sufficient to just run RSVP ...