RSVP on Frame-Relay

[kswonnell]

Why in the following configuration is it necessary to specify on the main interface, the sum total of reservations of the two subinterfaces? ie. 500 (350 + 150)

interface Serial3/0

encapsulation frame-relay

max-reserved-bandwidth 20

no fair-queue

frame-relay traffic-shaping

frame-relay lmi-type cisco

ip rsvp bandwidth 500 500

!

interface Serial3/0.1 point-to-point

ip address 10.1.1.1 255.255.0.0

frame-relay interface-dlci 101

class fr-voip

ip rsvp bandwidth 350 350

!

interface Serial3/0.2 point-to-point

ip address 10.3.1.1 255.255.0.0

frame-relay interface-dlci 201

class fast-vcs

ip rsvp bandwidth 150 150

ip rsvp pq-profile 6000 2000 ignore-peak-value

[jbohla]

I think the bandwidth reservation configuration under the main interface is optional. Depending on the version, IOS by default adds this command under the main interface with a value of 75% of the main interface bandwidth. If you want to change the value, you can configure the value as shown in your example with the sum of values under each sub-interface. Even if you remove this command from the main interface, the 'show ip rsvp interface' will still show that RSVP is configured under the sub-interfaces. So this seems to be optional which does not affect the functionality irrespective of whether it is configured or not under the main interface.