frame-relay fragment
Enables dual-FIFO, but how to get VoIP into the voice queue? Is rtp heasder compression enough to do this or is LLQ needed with a priority class?

I’d be inclined to think that RTP header compression has no influence over FRF.12 fragmentation, unless it matches RTP traffic into the propper FIFO queue (dual-FIFO). Seeing that FRF.12 enables dual-FIFO I can only assume this matching to be the case, I’ve not yet found a doc stating this without doubt. So please leave a note if you do.

Anyway I think it’s good to know both options. Dual-FIFO applies fragmentation only to the ‘data’ queue, I know this from Multiclass Multilink PPP (MC-MLPPP) which is also dual-FIFO. I use MC-MLPoA for QoS on DSL lines.

——- (Without FRTS)
# One config:
Int S0/0
frame-relay fragment 40 end-to-end
!
Int S0/0.1
frame-relay interface-dlci 1
frame-relay ip rtp header-compression

——- (With FRTS)
# Other config:
Class-map match-any voip
match protocol rtp audio
Policy-map FR-voip
class voip
# Enable PQ so the router can differentiate between flows (dual-FIFO)
priority
class class-default
!
map-class FR-voip+FRF12
service-policy output FR-voip
frame-relay fragment 40
!
Int S0/0
frame-relay traffic-shaping
!
Int S0/0.1
frame-relay interface-dlci 1
class FR-voip+FRF12

CCO: VoIP o F/R with QoS

Categories: CCIE R&S
Comments Off on F/R dual-FIFO