05-08-2008 06:11 AM - edited 03-03-2019 09:52 PM
Hi all
We have an 8mb ethernet bearer (10MB access) so I have attempted to configure a nested policy map to include traffic shaping.
If I apply the 8M_out map to the outgoing interface I do not see packets in the priority queue when I do "show policy-map interface f0". If I change the interface to use the QOS_out policy (which means I don't have shaping) the priorty queue is recording packets.
Have I configured this incorrectly?
Thanks
class-map match-any REAL_TIME
match ip dscp ef
match ip precedence 5
match ip dscp af31
match access-group name EF
match ip dscp cs2
class-map match-any MGT
match ip precedence 6
match ip precedence 7
match access-group name RIP
!
!
policy-map QOS_out
class MGT
bandwidth remaining percent 5
class REAL_TIME
priority 3500
set dscp ef
policy-map 8M_out
class class-default
shape average 8000000
service-policy QOS_out
Queueing
Strict Priority
Output Queue: Conversation 264
Bandwidth 3500 (kbps) Burst 87500 (Bytes)
(pkts matched/bytes matched) 1892/142908 <<<< These are 0 when 8M_out is used
(total drops/bytes drops) 0/0
Solved! Go to Solution.
05-08-2008 07:47 AM
This is expected behavior in this scenario. With the 8m_out policy applied to the interface, the queuing policy (QOS_out) will only become active if shaping is taking place. Shaping will only be active if you're exceeding 8Mb.
Hope this helps. If so, please rate the post.
Brandon
05-09-2008 04:39 AM
Logically, your configuration looks correct. As Brandon notes, until you load the shaper, queues won't form in the child policy. (A quick test, reduce the shaper's bandwidth to induce congestion earlier if you want to see the policy in action. Use with caution, as doing so would slow traffic in a production environment.)
Some other tips:
Router interfaces sometimes have a hardware FIFO queue that you can adjust, usually with the tx-ring-limit. For highly sensitive traffic like VoIP, you may need to adjust the hardware queue size smaller so the traffic is pushed into the software queues where your LLQ will send such traffic first. Likewise, you may need to decrease the time interval used by the shaper. (My experience has been, at least on some platforms and IOSs, a shaper used with a child policy seems to still maintain its own WFQ queues. Haven't found a method to minimize those so that the child policy queues handle congestion as desired.)
05-08-2008 07:47 AM
This is expected behavior in this scenario. With the 8m_out policy applied to the interface, the queuing policy (QOS_out) will only become active if shaping is taking place. Shaping will only be active if you're exceeding 8Mb.
Hope this helps. If so, please rate the post.
Brandon
05-09-2008 01:16 AM
I read this also.
Will voice still be ok in this scenario?
(Will rate ofc)
Thanks
05-09-2008 04:39 AM
Logically, your configuration looks correct. As Brandon notes, until you load the shaper, queues won't form in the child policy. (A quick test, reduce the shaper's bandwidth to induce congestion earlier if you want to see the policy in action. Use with caution, as doing so would slow traffic in a production environment.)
Some other tips:
Router interfaces sometimes have a hardware FIFO queue that you can adjust, usually with the tx-ring-limit. For highly sensitive traffic like VoIP, you may need to adjust the hardware queue size smaller so the traffic is pushed into the software queues where your LLQ will send such traffic first. Likewise, you may need to decrease the time interval used by the shaper. (My experience has been, at least on some platforms and IOSs, a shaper used with a child policy seems to still maintain its own WFQ queues. Haven't found a method to minimize those so that the child policy queues handle congestion as desired.)
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