Priority under Shaping

From: gladston@br.ibm.com
Date: Tue Jul 26 2005 - 16:25:43 GMT-3


Hi,

Am I wrong expecting a better round-trip time for traffic that receives priority on the queue formed by Shaping?

I could not notice it on tests. Tested CB Shaping and FRTS.

Whithout traffic, the round-trip average is 5ms for priority traffic.
When the link is saturated using SAA (jitter), the round-trip average is 109ms and there is no way to get a small time (on the test I did).

I tried to get a better time using these:

-Priority under CB Shaping
-LLQ under map-class frame-relay
-PQ under map-class frame-relay

With CB priority and LLQ I could check that priority packets are matched.

These are the times:

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 148.5.57.7, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 48/109/132 ms
Rack2R2(config-subif)#do pin 148.5.57.7

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 148.5.57.7, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 96/117/129 ms
Rack2R2(config-subif)#do pin 148.5.57.7

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 148.5.57.7, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/5/8 ms
Rack2R2(config-subif)#do pin 148.5.57.7

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 148.5.57.7, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/5/8 ms
Rack2R2(config-subif)#do pin 148.5.57.7

These are the configs:

For CB Shaping

 class-map match-all DLSW-priority
  match access-group 114
!
 policy-map Child-priority-dlsw
  class DLSW-priority
   priority 64
 policy-map CB-Shaping-and-priority
  class class-default
   shape average 128000 16000 1000
   service-policy Child-priority-dlsw
!
int ser 0/0.235
 service-police output CB-Shaping-and-priority

For FRTS

class-map match-all Priority-under-Shaping
  match access-group 132
!
policy-map Priority-under-Shaping
  class Priority-under-Shaping
   priority 64
!
int ser 0/0
frame-relay traffic-shaping
frame interface-dl 502
 class Shaping-to-r2
!
map-class fra Shaping-to-r2
 service-policy out Priority-under-Shaping

Monitoring for CB Shaping:

Rack2R2#sh pol int ser 0/0.235

 Serial0/0.235

  Service-policy output: CB-Shaping-and-priority

    Class-map: class-default (match-any)
      1007047 packets, 64489391 bytes
      5 minute offered rate 188000 bps, drop rate 59000 bps
      Match: any
      Traffic Shaping
           Target/Average Byte Sustain Excess Interval Increment
             Rate Limit bits/int bits/int (ms) (bytes)
           128000/128000 2125 16000 1000 125 2000

        Adapt Queue Packets Bytes Packets Bytes Shaping
        Active Depth Delayed Delayed Active
        - 0 718864 46045640 682359 43687588 yes

      Service-policy : Child-priority-dlsw

        Class-map: DLSW-priority (match-all)
          755 packets, 49824 bytes
          5 minute offered rate 0 bps, drop rate 0 bps
          Match: access-group 114
          Queueing
            Strict Priority
            Output Queue: Conversation 24
            Bandwidth 64 (kbps) Burst 1600 (Bytes)
            (pkts matched/bytes matched) 461/36268
            (total drops/bytes drops) 0/0

        Class-map: class-default (match-any)
          738922 packets, 47304513 bytes
          5 minute offered rate 187000 bps, drop rate 59000 bps
          Match: any

Monitoring for FRTS:

Rack2R5(config-if)#do sh fram pvc 502

PVC Statistics for interface Serial0/0 (Frame Relay DTE)

DLCI = 502, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0

  input pkts 873443 output pkts 889948 in bytes 55946844
  out bytes 57035216 dropped pkts 968 in pkts dropped 0
  out pkts dropped 968 out bytes dropped 62102
  late-dropped out pkts 968 late-dropped out bytes 62102
  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 500 out bcast bytes 72475
  5 minute input rate 79000 bits/sec, 155 packets/sec
  5 minute output rate 87000 bits/sec, 182 packets/sec
  pvc create time 02:41:56, last time pvc status changed 02:41:33
  cir 128000 bc 128000 be 0 byte limit 2000 interval 125
  mincir 64000 byte increment 2000 Adaptive Shaping none
  pkts 16 bytes 1450 pkts delayed 0 bytes delayed 0
  shaping inactive
  traffic shaping drops 0
  service policy Priority-under-Shaping
 Serial0/0: DLCI 502 -

  Service-policy output: Priority-under-Shaping

    Class-map: Priority-under-Shaping (match-all)
      12 packets, 1188 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: access-group 132
      Queueing
        Strict Priority
        Output Queue: Conversation 24
        Bandwidth 64 (kbps) Burst 1600 (Bytes)
        (pkts matched/bytes matched) 0/0
        (total drops/bytes drops) 0/0

    Class-map: class-default (match-any)
      5 packets, 320 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any
  Output queue size 0/max total 600/drops 0



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