[nsp] WAN traffic management

From: Art Houle (houle@zeppo.acns.fsu.edu)
Date: Tue Apr 02 2002 - 09:36:59 EST


Hello,

  We have a cisco 7507 with PA-A3-OC3 ATM interface on a VIP4-80 connected
to our ISP with a 45Mbps CIR. On our core network we are marking DSCP bits
for all traffic so that we can selectivly drop less important traffic at
our expensive WAN links.

  To date we have failed to implement "Class Based Weighted Fair Queueing"
(CBWFQ). This seems like the most efficient mechanism for controlling our
traffic. This seemed to work with a policy that had 'shape average' but
that drove our VIP CPU to 100% (with only 10Mbps traffic during spring
break) and transit times to our ISP varied up to 3000ms with lots of user
complaints. We had to back that out. Our current interim solution is:

=====================
policy-map policeISP-out
  class class-default
    random-detect dscp-based
    fair-queue
     police 45000000 22500 22500 conform-action transmit exceed-action drop
 
interface ATM4/0/0.4 point-to-point
 ip address x.x.x.x 255.255.255.252
 ip access-group 140 in
 ip access-group 145 out
 no ip redirects
 no ip proxy-arp
 ip split-horizon
 pvc 0/155
  ubr 45000
  oam-pvc manage 1
  oam retry 3 5 1
 !
 service-policy output policeISP-out
=====================
  this results in FIFO queueing with drops that are not keyed to DSCP
values... so we loose our BGP and DNS traffic in addition to our napster
traffic...
=====================
rsb-7507#sho policy-map int atm 4/0/0.4
 ATM4/0/0.4
  service-policy output: policeISP-out
    class-map: class-default (match-any)
      56047666 packets, 42473755239 bytes
      30 second offered rate 39216000 bps, drop rate 5110000 bps
      match: any
        56047666 packets, 42473755239 bytes
        30 second rate 39216000 bps
      queue size 6, queue limit 11249
      packets output 52196496, packet drops 3859749
      tail/random drops 0, no buffer drops 0, other drops 3859749
      random-detect:
        Exp-weight-constant: 9 (1/512)
        Mean queue depth: 4
        Class Random Tail Minimum Maximum Mark Output
                drop drop threshold threshold probability packets
        0 0 0 2812 5624 1/10 6710443
        8 0 0 3163 5624 1/10 25031155
        16 0 0 3515 5624 1/10 1339585
        24 0 0 3866 5624 1/10 18860220
        48 0 0 4921 5624 1/10 2024
        56 0 0 5272 5624 1/10 253059
      fair-queue: per-flow queue limit 2812
      police:
        45000000 bps, 22500 limit, 22500 extended limit
        conformed 52196339 packets, 38131308564 bytes; action: transmit
        exceeded 3365244 packets, 3738952907 bytes; action: drop
        violated 494417 packets, 610351336 bytes; action: drop
        conformed 36088000 bps, exceed 3910000 bps violate 1197000 bps
=====================

We have been asking our local cisco office for help with this for months
and they have not suplied a workable CBWFQ solution yet.
 
Has anybody got CBWFQ to work with a a 7507? a 6509 on integrated IOS?
how about a Juniper box?

thank you for any help.

Art Houle e-mail: houle@acns.fsu.edu.
Academic Computing & Network Services Voice: 850-644-2591
Florida State University FAX: 850-644-8722



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