QOS(Priority command)on WS-X6408A-GBIC in outbound direction

Unanswered Question
Mar 18th, 2009

Hi All,

We are trying to figure out prioritizing voice traffic to around 20 percent of the link bandwidth in the outbound direction on WS-X6408A-GBIC by the below command

policy-map <name>

class <name>

priority percent 20

!

class-map match-any <name>

match access-group <name>

!

ip access-list extended <name>

.When applying the service policy on outbound direction,it gives an error message saying priority command is not supported on outbound direction on this interface.

Is there a way were we could prioritize without using the priority command or I am missing something .

Any help is really appreciated.

Thanks

Regards

Anantha Subramanian Natarajan

I have this problem too.
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anasubra_2 Wed, 03/18/2009 - 14:43

Hi John,

Thanks for the reply.Will go through the link and if I stumble somewhere ,I would kindly request your assistance.

Thanks

Regards

Anantha Subramanian Natarajan

anasubra_2 Fri, 03/20/2009 - 14:00

Hi John,

Went through the link and I couldn't make up a configuration which would do my requirement.I am sure missing something but would appreciate any help.

Me trying to do is to classify packets based on ip address on outbound direction and put those on priority queue and assign a value of 20% of bandwidth and rest take the default non-queue.

Thanks

Regards

Anantha Subramanian Natarajan

Edison Ortiz Fri, 03/20/2009 - 14:32

Anantha,

You need to mark incoming packets to DSCP EF with an ACL so they can be placed in priority queue during egress.

ip access-list extended|standard DSCP-EF

permit ....

class-map DSCP-EF

match ip access-group name DSCP-EF

policy-map DSCP-EF

class DSCP-EF

set ip dscp ef

interface fx/x

mls qos vlan-based

interface vlan x

service-policy input DSCP-EF

Your module does not allow you to modify the priority queue limits.

http://www.cisco.com/en/US/docs/ios/qos/command/reference/qos_n1.html#wp1015758

It's set to 15% of the interface bandwidth, thus you don't need to do anything on egress. Any traffic matching the ACL will get 15% priority treatment.

HTH,

__

Edison.

anasubra_2 Fri, 03/20/2009 - 15:07

Hi Edison,

Thank you very much for the explanation.But I find missing something basic here.Let me try to explain the exact scenario and will try to assist you on my confusion.

A customer edge router (CE1) is connected to MPLS PE router (PE1) and similarly CE2 connects to PE2 as shown below

CE1-PE1-MPLS CLOUD- PE2- CE2

When a packet comes from CE1 with a specific ip address subnet we classify those into a priority class and police to there CIR value and impose a EXP bit(We preserve the packet TOS values(may be DSCP or IP Prec) while travelling in the MPLS cloud.If the destination of the packet is destined to CE2 lan network,we would like to match the ip source subnet from CE1 and want those to put into priority queue in the outbound of PE2 and we would also want to keep whatever the customer QOS values while going to CE2.

Keeping the above as requirement,now in PE2 outgoing interface,how to use the above config.I am able to get the class-map,access-list but not policy-map where we call the class-map and set the dscp value.

Also couldn't understand why mls qos is vlan-based.

Kindly help me to understand the same or even anylink,which may help to understand it.

Thanks

Regards

Anantha Subramanian Natarajan

Edison Ortiz Fri, 03/20/2009 - 17:20

Anantha,

If the PE1 is the 6500 in question, do as I suggested. EF marking will become MPLS Experimental 5 and once if gets to PE2 and the MPLS to IP takes place, the packet will be received as EF. EF will be considered priority queuing throughout.

The mls qos vlan-based allows you to place the service-policy on the SVI instead of the interface.

The document Jon illustrated mentions its use. Please take a moment and read the entire document. It has all the tools you need.

It does take time to understand it but if you want to implement QoS in the 6500 and know what the commands can do, you need to read that document.

__

Edison.

anasubra_2 Sat, 03/21/2009 - 06:05

Hi Edison,

Thank you for the reply.

Our concern in this is ,if we mark the traffic as EF for priority traffic at ingress and then impose the EXP bit 5,I would assume, when it leaves the PE2 to CE2 ,the packet will have marking as EF.We would like to have whatever the customer as marked for priority traffic (It doesn't necessarily be EF),so that customer will have is own QOS doamin and the SP will have its own QOS domain.Please let me know,how I can retain the customer marking once it leaves the PE2.

Also,we would like to use the service-policy on port level instead of SVI,is that can be done ?

I will try to go through the doc again,meantime,any assistance is appreciated.

Thanks

Regards

Anantha Subramanian Natarajan

Edison Ortiz Sat, 03/21/2009 - 07:18

So, you are the Service Provider and want to perform QoS only on the MPLS network while leaving the customer QoS intact.

In this case, you are very limited on the things you can do with the current hardware.

I highly suggest to purchase some SIP/SPA modules which provide modular QoS in the 6500. With modular QoS, you can implement the syntax you presented originally which works in IOS routers.

With your current hardware, you can potentially create 2 classes (your hardware is limited to 2 queues and 1 priority queue) and match the customer QoS at ingress then impose MPLS EXP 5 for priority class and MPLS EXP 0 for everything else.

HTH,

__

Edison.

Edison Ortiz Sat, 03/21/2009 - 08:08

Also,we would like to use the service-policy on port level instead of SVI,is that can be done ?

Sorry, I missed this question before. Yes, you can apply the service-policy inbound from the customer router under the interface.

__

Edison.

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