Traffic shaping on F/R using MQC

From: Dale Shaw (dale.shaw@gmail.com)
Date: Fri Feb 27 2009 - 00:54:15 ARST


Hi all,

Re: traffic shaping on Frame Relay links using the MQC (as distinct from FRTS)

Is there any functional difference between the following two configs? See below:

Configuration #1:

class-map match-all FR-R2
 match fr-dlci 102
class-map match-all FR-R3
 match fr-dlci 103
class-map match-all FR-R4
 match fr-dlci 104
!
policy-map THING
 class FR-R2
  shape average 64000 8000 0
  shape adaptive 32000
 class FR-R3
  shape average 128000 16000 0
  shape adaptive 64000
 class FR-R4
  shape average 192000 24000 0
  shape adaptive 96000
!
interface Serial0/0/0
 ip address 10.1.1.1 255.255.255.0
 encapsulation frame-relay
 load-interval 30
 frame-relay map ip 10.1.1.2 102
 frame-relay map ip 10.1.1.3 103
 frame-relay map ip 10.1.1.4 104
 no frame-relay inverse-arp
 service-policy output THING

Configuration #1 "sh policy-map interface" output:

R1#sh policy-map int s0/0/0 out

 Serial0/0/0

  Service-policy output: THING

    Class-map: FR-R2 (match-all)
      3226 packets, 4616500 bytes
      30 second offered rate 64000 bps, drop rate 0 bps
      Match: fr-dlci 102
      Traffic Shaping
           Target/Average Byte Sustain Excess Interval Increment
             Rate Limit bits/int bits/int (ms) (bytes)
            64000/64000 1000 8000 0 125 1000

        Adapt Queue Packets Bytes Packets Bytes Shaping
        Active Depth Delayed Delayed Active
        - 3 3223 4612240 1150 1612073 yes
[...]

Configuration #2:

policy-map THING-R2
 class class-default
  shape average 64000 8000 0
  shape adapt 32000
!
policy-map THING-R3
 class class-default
  shape average 128000 16000 0
  shape adapt 64000
!
policy-map THING-R4
 class class-default
  shape average 192000 24000 0
  shape adapt 96000
!
map-class frame FR-R2
 service-policy out THING-R2
!
map-class frame FR-R3
 service-policy out THING-R3
!
map-class frame FR-R4
 service-policy out THING-R4
!
interface Serial0/0/0
 ip address 10.1.1.1 255.255.255.0
 encapsulation frame-relay
 load-interval 30
 frame-relay map ip 10.1.1.2 102
 frame-relay map ip 10.1.1.3 103
 frame-relay map ip 10.1.1.4 104
 no frame-relay inverse-arp
 frame-relay interface-dlci 102
  class FR-R2
 frame-relay interface-dlci 103
  class FR-R3
 frame-relay interface-dlci 104
  class FR-R4

Configuration #2 "sh policy-map interface" output:

R1#sh policy-map int s0/0/0 out
 Serial0/0/0: DLCI 102 -

  Service-policy output: THING-R2

    Class-map: class-default (match-any)
      1537 packets, 2214376 bytes
      30 second offered rate 64000 bps, drop rate 0 bps
      Match: any
      Traffic Shaping
           Target/Average Byte Sustain Excess Interval Increment
             Rate Limit bits/int bits/int (ms) (bytes)
            64000/64000 1000 8000 0 125 1000

        Adapt Queue Packets Bytes Packets Bytes Shaping
        Active Depth Delayed Delayed Active
        BECN 3 1534 2210116 1533 2208612 yes
[...]

Configuration #2 provides cleaner/more intuitive output in "show
policy-map interface" (e.g. shows the discrete DLCIs the policies are
applied to). It's not clear to me whether Configuration #1 results in
a functional adaptive shaping configuration, either, since the "show
policy-map interface" output says nothing about BECNs.

In terms of the actual shaping rate, both configurations seem to have
the desired effect:

R1#sh int s0/0/0 | i output rate
  30 second output rate 384000 bits/sec, 33 packets/sec

(this is with R2 (64Kbps), R3 (128Kbps) and R4 (192Kbps) all
transferring an IOS image from R1 using HTTP -- total = 384Kbps)

cheers,
Dale

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