In a FR scenario (hub and spoke topology) at hub side A I have two pvc each one for the two remote sides B and C.
Hub side A has line speed 2Mbps, one spoke side B has line speed 2mbps and the other C has line speed 64kbps.
Both pvcs cir are 48kbps.
Now on one pvc, suppose AB, we need to have voip and data traffic and on the other pvc AC only data traffic.
We will use LLQ, FR traffic shaping and the other QoS features.
For AB pvc traffic classification:
match access-group 100
map-class frame-relay pvc-AB
no frame-relay adaptive-shaping becn
frame-relay cir 48000
frame-relay bc 480
frame-relay be 0
frame-relay mincir 48000
service-policy output qos-AB
frame-relay fragment 60
For pvc AC traffic classification:
match access-group 101
bandwidth 36 (75% of mincir)
map-class frame-relay pvc-AC
frame-relay adaptive-shaping becn
frame-relay cir 64000
frame-relay bc 6000
frame-relay be 2000
service-policy output qos-AC
In first case AB we use a "conservative approach" : no adaptive shaping and cir=mincir=48kbps.
So the FR subinterface for the pvc AB has a "well know" bandwidth and if I configure the statement "bandwidth 48" in subinterface I think it could not be ambiguous.
interface s0.20 point-to-point
description pvc AB
In second case pvc AC, we don't use a conservative approach so traffic can exceed mincir and subinterface bandwidth isn't "well know" !
In queues and traffic flows bandwidths/weigths calculation, LLQ/WFQ algorithm uses, if configured, the mincir to determine the available bandwidth.
The "bandwidth" statement in interface configuration has other important uses for example in interface load calculation, dynamic routing....
For pvc AC subinterface where approach is NOT conservative and bandwidth fluctuates, the use of "bandwidth 48" (mincir) statement
interface s0.50 point-to-point
description pvc AC
could be AMBIGUOUS for queues and traffic flows bandwidths/weigths calculation or it is mandatory ?
1. You need to add CIR to your frame-relay maps
not micCIR. MinCIR is only looked at when we're doing adptive
shaping for refereal to drop down level.
2. If you add a bandwidth statement on an interface, it has nothing to do
with the actual frame forwarding over the DLCI, its mostly for routing protocol
use. The traffic queue is kick off by conjection which is measured against CIR and
not interface bandwidth statement.
3. It is mandatory that you have a CIR, BC configured for mapp-class frame-relay when doing