QoS Turst for Cisco 4948E switch

Answered Question
Aug 17th, 2011

I am trying to trust the marking for voice traffic in a Cisco 4948E interface/port and it looks like the "qos" command is not working as described in the  command reference.

Is there any particular way to configure a port to trust the QoS marking received in a Cisco 4948E - 10GIG switch?

I have this problem too.
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Correct Answer by Edison Ortiz about 2 years 8 months ago

I'm not sure what you find unclear. The QoS behavior has changed and the URL I posted indicates the hardware affected by this change. The 4900 switch is not the same platform/hardware as the 4948E switch.

You need to follow the documentation on the platform in question to configure QoS per your needs.

As I stated before, you need to implement MQC based QoS with policy maps inbound and outbound.

Switchport QoS trust is enabled by default and these isn't any mls qos related commands anymore.

QoS on newer platforms are similar to the behavior you would experience on a regular IOS router.

Regards,

Edison

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harris-sprint Thu, 08/18/2011 - 12:46

Hello Edson,

Thanks for the information. But that is not so clear as we think.

What I found is in the 4900 configuration guide for QoS. A note on QoS trust boundaries.

Cisco built the IOS for this switch considering that Cisco IP phone will wil be connected to the ports. but that is not always the case. On my case for example the customer has an AVAYA PBX - analog with an IP gateway.

So the sequence I found to apply on the interface to trust their marking is:

1- apply command: "switchport priority extend trust"

2 - apply command "cdp enable"

I am still waiting to test it. If you can test - please let me kow the results.

The frustration comes from the fact taht you expect something like "mls qos trust" or "qos trust dscp"

Thanks,

Gilson

Correct Answer
Edison Ortiz Thu, 08/18/2011 - 21:11

I'm not sure what you find unclear. The QoS behavior has changed and the URL I posted indicates the hardware affected by this change. The 4900 switch is not the same platform/hardware as the 4948E switch.

You need to follow the documentation on the platform in question to configure QoS per your needs.

As I stated before, you need to implement MQC based QoS with policy maps inbound and outbound.

Switchport QoS trust is enabled by default and these isn't any mls qos related commands anymore.

QoS on newer platforms are similar to the behavior you would experience on a regular IOS router.

Regards,

Edison

MachadoGB Wed, 08/24/2011 - 12:53

Hi Edison,

You are correct about the MQC and the trust behavior of the 4948E. I will use the MQC and apply the policy I need.

But what still bugging me is the fact hat the 4948E I have only accepts the "qos control-packets" command instead of the normal qos command.

Thanks,

Gilson

gnijs Fri, 04/20/2012 - 06:11

MachadoGB is completely right. The switch is marketed as server farm access switch, however , it uses completely different syntax for QOS as compared to C3750/C3750X or C3750G. From operational standpoint, this increases cost and only adds to confusion (just lost 1 day of figuring it out) and i am already getting questions from the Operational department "why can't i just put mls qos trust dscp on it". Furthermore, our servers are all untrusted by default, which matches fine with the previous model. Now we just introduced a switch where by default all is trusted...only adds to the confusion...

JosephDoherty Fri, 04/20/2012 - 10:37

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gnijs wrote:

MachadoGB is completely right. The switch is marketed as server farm access switch, however , it uses completely different syntax for QOS as compared to C3750/C3750X or C3750G. From operational standpoint, this increases cost and only adds to confusion (just lost 1 day of figuring it out) and i am already getting questions from the Operational department "why can't i just put mls qos trust dscp on it". Furthermore, our servers are all untrusted by default, which matches fine with the previous model. Now we just introduced a switch where by default all is trusted...only adds to the confusion...

Laugh - darn Cisco for making changes.

Now if only CatOS and IOS and NX-OS were all exactly alike.

Now if only different Catalyst switch family features and configurations were all exactly alike (including QoS).

Now if only different IOS version features were all exactly alike.

But wait - it's not just Cisco, if the industry as whole would only stop making changes too.

I really never understood why punched cards fell out of favor, which is what I started with.  I even remember the extra time it took me to learn some of the new features of the IBM 129 card punch vs. the IBM 26 and 29 models, and the end result was still just a punched card.  It had some really confusing operational changes too, no physical program drum, didn't punch the card until you finished the whole card, a LED counter to indicate your current column.

I also so much preferred carrying my personal data files around on 2400' tapes (think I still got one in my closet) than these modern USB sticks too.  The latter are so much easier to mislay somewhere and not notice.  The former is also much more fun to watch in operation.  Lastly, the protect rings are much fun to toss across the office at coat hooks; try that with a USB stick.

So again laugh - of course there's issues with changes such as adding confusion, but are you really arguing depending how the switch is marketed or that you might lose a day figuring out some differences nothing shouldn't be changed?

kishore.chennupati Sat, 04/21/2012 - 07:12

I also so much preferred carrying my personal data files around on 2400' tapes (think I still got one in my closet) than these modern USB sticks too.  The latter are so much easier to mislay somewhere and not notice.  The former is also much more fun to watch in operation.  Lastly, the protect rings are much fun to toss across the office at coat hooks; try that with a USB stick.

LOL @ dat

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