Frame Relay Traffic Shaping - Part II

In this post i look at applying WRED within the frame-relay traffic shaping construct.

Assume interface s2/0 already has frame-relay traffic shaping enabled.

interface Serial2/0
bandwidth 1544
ip address 174.1.145.4 255.255.255.0
ip pim sparse-dense-mode
encapsulation frame-relay
delay 2
serial restart-delay 0
no fair-queue
frame-relay class FR
frame-relay traffic-shaping
frame-relay map ip 174.1.145.1 401 broadcast
frame-relay map ip 174.1.145.4 401
frame-relay map ip 174.1.145.5 401 broadcast
end

The frame-relay map class FR is already applied

map-class frame-relay FR
frame-relay cir 128000
frame-relay bc 16000
frame-relay adaptive-shaping becn
frame-relay fecn-adapt

At this point there is a requirement to apply WRED to IP packets with 'critical' ip precedence. As denoted in an earlier post of mine this can be achieved within MQC via application to a service policy that either has 'bandwidth' applied or must be done in the 'class default' with fair-queue applied. As there are no bandwidth requirements here i use the 'class default' option.


policy-map WRED
class class-default
fair-queue
random-detect
random-detect precedence 5 60 90 5

With the above parameters ip packets with a priority of 5 will start to be dropped once the queue size reaches 60. Once the queue size reaches 90, 1 in 5 packets will be dropped.

To apply a policy to a frame-relay map the same method is used as applying to an interface.

Thus

map-class frame-relay FR
service-policy output WRED

Once applied use the 'show frame-relay pvc' command to examine the settings.

Rack1R4#s frame-relay pvc 401

PVC Statistics for interface Serial2/0 (Frame Relay DTE)

DLCI = 401, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial2/0

input pkts 329 output pkts 294 in bytes 26959
out bytes 18027 dropped pkts 16 in pkts dropped 16
out pkts dropped 0 out bytes dropped 0
in FECN pkts 0 in BECN pkts 0 out FECN pkts 0
out BECN pkts 0 in DE pkts 0 out DE pkts 0
out bcast pkts 198 out bcast bytes 11496
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
Shaping adapts to BECN
pvc create time 00:26:31, last time pvc status changed 00:24:52
cir 128000 bc 16000 be 0 byte limit 2000 interval 125
mincir 64000 byte increment 2000 Adaptive Shaping BECN
pkts 212 bytes 12481 pkts delayed 0 bytes delayed 0
shaping inactive
traffic shaping drops 0
service policy WRED
Serial2/0: DLCI 401 -
Service-policy output: WRED

Class-map: class-default (match-any)
187 packets, 11007 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: any
Queueing
Flow Based Fair Queueing
Maximum Number of Hashed Queues 16
(total queued/total drops/no-buffer drops) 0/0/0
exponential weight: 9

class Transmitted Random drop Tail drop Minimum Maximum Mark
pkts/bytes pkts/bytes pkts/bytes thresh thresh prob
0 0/0 0/0 0/0 20 40 1/10
1 0/0 0/0 0/0 22 40 1/10
2 0/0 0/0 0/0 24 40 1/10
3 0/0 0/0 0/0 26 40 1/10
4 0/0 0/0 0/0 28 40 1/10
5 0/0 0/0 0/0 60 90 1/5
6 72/4237 0/0 0/0 32 40 1/10
7 0/0 0/0 0/0 34 40 1/10
rsvp 0/0 0/0 0/0 36 40 1/10


Output queue size 0/max total 600/drops 0