IP precedence is really unecessary if you are
doing voip over frame-relay. The queuing mechanism would
be Ip rtp priority which create two queues. A high
queue for voip traffic and a low queue populated by the queue
mechanism used for data traffic. In the example below it is
WFQ.
Also to ensure good voice quality, large data packets
should be fragmented to reduce the propagation time across the link. The
frame relay tc should be kept at a small value to reduce
the maximum time we will need to wait for a token ( i.e. clocking of next frame on the wire)
Example below shown how these issues are addressed.
Interface ethernet 0
ip address 2.2.2.1 255.255.255.0
!
int ser 0/0
encap frame-relay
frame-relay traffic-shaping
no ip address
!
interface serial0/0.1 point-to-point
ip add 1.1.1.1 255.255.255.252
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