ā08-06-2010 10:11 AM - edited ā03-06-2019 12:21 PM
Hello expert,
I have a hub and spoke enviroment using all cisco 2811 routers.
I am currently working on qos.
I have apply class -maps and policy-map on one router close to the source as per best practice.
I went to second router and configure qos, i tried to use class-map match dscp21 etc ---- since i do not want to remark packets
previously marked at the source.
The problem is that when i check the second router using the sh policy-map int I am only see all the packets being queued under class-default
which suggest that the match dscp21 etc is not working.
Is there a something missing do i have to issue some command etc to allow the other sister routers to trust the orginal marking.
Attached are two file for clarification
Regards
Solved! Go to Solution.
ā08-11-2010 10:06 AM
1) You need to enable QOS globally on the switch ie.
2960(config)# mls qos
2) the "mls qos trust dscp" command is an interface command not a global config command so if you need to apply it at the interface level eg.
2960(config)# int gi0/1
2960(config-if)# mls qos trust dscp
Jon
ā08-11-2010 10:20 AM
Yup, exactly what Jon posted.
Geez Jon the notification email and your response came in at the same time. You're now faster than email.
ā08-09-2010 12:41 PM
A couple of things to keep in mind. 1. Packets are only placed into your configured queues when the tx ring is full. If the interface is not congested packets will not go into the queues you have setup, they will go into the default queue. 2. It looks like your applying QoS to an internet link. If so, keep in mind that some Service Providers strip the CoS values from your packets.
Hope it helps.
ā08-09-2010 01:19 PM
Hello Collin,
>> Packets are only placed into your configured queues when the tx ring is full. If the interface is not congested packets will not go into the queues you have setup, they will go into the default queue
While awaiting your response I removed the class mappings as per attactment and created new class mappings.
And the respective queues where populated as per mapping
See attachment.
>> It looks like your applying QoS to an internet link. If so, keep in mind that some Service Providers strip the CoS values from your packets.
Sorry for the misleading naming of the policy-map this policy is actual link to the lan interface of the second router as the aim is just see if the
mapping created on Router1 will remain the same when they hit Router 2.
I am trying to let one Router do all the inpection and marking of the packets and the other routers just accept the mark packets.
Regards
ā08-09-2010 08:33 PM
If you are marking on router 1 and router 2's Ethernet is in the path of that marked traffic it should show up and match your policy coming into router 2, but It doesn't appear to. my first guess is that your LAN switch is remarking it. If your LAN switch is a 2950 or a 2960/3560/3750 with qos enabled you will have to make sure the ports you have your routers attached to are set to trust dscp on the switch.
ā08-10-2010 05:40 AM
Hello Colin,
My Lan switch may be the problem I have 2960 series at all locations.
But did not set the respective ports that the router is connected to trust dscp.
Colin, if i do not want to trouble my switch will I have to setup class markings on all my routers?
Regards
Jomo
ā08-10-2010 06:11 AM
Best practices is exactly what relsethagen stated, use the trust feature under the LAN switch interface. Always mark as close to the source as possible and trust the marking for as far as possible. The router will have to write to COS. Yes you can setup it marking on the router, but remember that QoS in switches is done in hardware asics and QoS in routers is done by CPU/software. It's much more efficient to perform QoS in switches than it is in routers.
mls qos trust dscp
If you want it really easy, enable auto qos on your devices. You will then need to add the command below instead of the one above (you can have both with no ill effects).
auto qos voip trust
Hope it helps.
ā08-11-2010 10:00 AM
Hello Colin,
Can please assist i getting and error when enabling
mls qos trust dscp on my switch.
All detail below for your guidance.
Switch info.
------------------------------------
Switch Ports Model SW Version SW Image
------ ----- ----- ---------- ----------
* 1 50 WS-C2960-48TT-L 12.2(25)SEE3 C2960-LANBASE-M
When I attempt to enable trust dscp
------------------------------------------------------------------
Linden> en
Password:
Linden#config t
Enter configuration commands, one per line. End with CNTL/Z.
Linden(config)#mls qos trust dscp
^
% Invalid input detected at '^' marker.
Linden(config)#
Checking mls for all the options
------------------------------------------------------------
Linden(config)#mls ?
qos qos keyword
Linden(config)#mls qos ?
aggregate-policer Named aggregate policer
map qos map keyword
queue-set Choose a queue set for this queue
rewrite Rewrite Packet/Frame
srr-queue Configure SRR receive queues
When I issue show mls
-------------------------------------------------------------------------------
Linden>sh mls qos
QoS is disabled
QoS ip packet dscp rewrite is enabled
ā08-11-2010 10:06 AM
1) You need to enable QOS globally on the switch ie.
2960(config)# mls qos
2) the "mls qos trust dscp" command is an interface command not a global config command so if you need to apply it at the interface level eg.
2960(config)# int gi0/1
2960(config-if)# mls qos trust dscp
Jon
ā08-11-2010 10:20 AM
Yup, exactly what Jon posted.
Geez Jon the notification email and your response came in at the same time. You're now faster than email.
ā08-11-2010 02:24 PM
Collin_Clark wrote:
Yup, exactly what Jon posted.
Geez Jon the notification email and your response came in at the same time. You're now faster than email.
Collin, got a lot of time on my hands at the moment due to a bike accident (mountain bike that is) so that probably explains it
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