Is Low MTU (ie 320) for VoIP over Frame-relay can be used to avoid serialization delay for large dat...

admin_2 · ‎06-24-2002

In order to provide voice quality for VoIP, is FR fragmentation equivalent to lowering the MTU size for the serial subinterface of a Frame relay subinterface?

Is there any isues like stop communications, using Low MTU ?

Report Inappropriate Content · ‎06-24-2002

If the router belongs to any of the

platform listed below, then use

FRF12 for you fragmentation. The MTU size

lowering also works but this can cause a high over

head as it can't be specified on a per dlci level.

With multiple dlci i.e. subinterfaces use per dlci fragmentation.. this helps reduce the overhead of changing the MTU size of the physical interface.

Snip config example.( __Must be configured on both side of the termination___)

PHONE 3333312---ROUTERA ----DLCI 100----ROUTERB ---PHONE 2111123

ROUTER A

!

dial-peer voice 1 voip

destination-pettern 2T

session target ipv4:10.10.10.2

!

int ser 0/0

encap frame-relay

frame-relay traffic-shaping

no ip address

!

interface serial0/0.1 point-to-point

ip add 10.10.10.1 255.255.255.252

frame-relay interface-dlci 100

class voice

!

map-class frame-relay voice

frame cir 64000

frame bc 640

frame mincir 64000

frame-relay ip rtp priority 16384 16383 48

frame fragment 80

frame fair-queue 64 256 0

ROUTER B

!

dial-peer voice 3 voip

destination-pettern 3T

session target ipv4:10.10.10.1

!