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BGP_down due to service policy

Unanswered Question
Apr 11th, 2012
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Hi,


After upgrade from 10 Mbps to 20 Mbps BGP down,if we remove the  services policy immediately BGP came up.


!

class-map match-any COS3

match ip dscp cs1

class-map match-any COS2

match ip dscp cs4

match ip dscp af21

match access-group name COS2_LIST

class-map match-any COS1

match ip dscp cs6

match ip dscp ef

match ip dscp af31

match ip dscp cs3

!

!

policy-map pune-troy-qos

class COS1

  set ip dscp cs5

    priority percent 25

class COS2

  set ip dscp cs4

    bandwidth percent 20

class COS3

  set ip dscp cs2

    bandwidth percent 5

     random-detect dscp-based

class class-default

  set ip dscp default

    fair-queue

     random-detect dscp-based

policy-map shape-zzz-20

class class-default

    shape average 20480000

  service-policy pune-troy-qos

!

if we remove service policy output shape-zzz-20  from WAN interface immediately BGP came up.

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Vasileios Boulo... Fri, 04/13/2012 - 02:37
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Hi Karthikeyan,


Does the BGP flap only during traffic congestion?

If yes, I would recommend to match to the class COS1 also the IP prec = 6 value.

This is the default value that is used for BGP packets and you can cross check this by running the sh ip bgp neighbor command. So, the BGP (network Control traffic) is prioritized to the LLQ class.

Apply again the Service Policy and check if the Class matchs IP-Prec traffic and hopefully BGP will not flap anymore.


Hope that helps!

Vasilis

searskarthik Fri, 04/13/2012 - 03:23
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Thansks  Vasilis,


even witout traffic BGP not up,if I removed service policy from Int Gi0/1 immediately BGP came up.



#sh policy-map shape-ZZZ-10

  Policy Map shape-ZZZ-10

    Class class-default

      Average Rate Traffic Shaping

      cir 10240000 (bps)

      service-policy pune-troy-qos

#sh policy-map  pune-troy-qos

  Policy Map pune-troy-qos

    Class COS1

      set ip dscp cs5

      priority 25 (%)

    Class COS2

      set ip dscp cs4

      bandwidth 20 (%)

    Class COS3

      set ip dscp cs2

      bandwidth 5 (%)

       packet-based wred, exponential weight 9


      dscp    min-threshold    max-threshold    mark-probablity

      ----------------------------------------------------------

      default (0)   -                -                1/10

    Class class-default

      set ip dscp default

      fair-queue

       packet-based wred, exponential weight 9


      dscp    min-threshold    max-threshold    mark-probablity

      ----------------------------------------------------------

      default (0)   -                -                1/10

#sh class-map COS1

Class Map match-any COS1 (id 3)

   Match ip  dscp cs6 (48)

   Match ip  dscp ef (46)

   Match ip  dscp af31 (26)

   Match ip  dscp cs3 (24)


#sh class-map COS2

Class Map match-any COS2 (id 2)

   Match ip  dscp cs4 (32)

   Match ip  dscp af21 (18)

   Match access-group name COS2_LIST

Ivan Krimmel Fri, 04/13/2012 - 03:32
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Hi Karthikeyan,


while in the problem state, could you provide:


sh policy-map int wan_int output

sh policy-map int wan_int output class


please?


Thanks,

Ivan.

Kishore Chennupati Fri, 04/13/2012 - 19:08
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Karthik,


Let me ask you a question. Did this work when you had the same policy for 10Mbps. I mean all you did was to upgrade the link from 10Mbs to 20Mbps right? or is it the first time you are applying Qos


Regards Kishore

Vasileios Boulo... Fri, 04/13/2012 - 02:46
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I assume that you do not have errors/drop/CRC to your interface and any Control plane policy configured in this router.


Regards,

Vasilis

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