Cisco QoS best practice for campus, data center, WAN

[gavin han]

How to find Cisco best practice CVD for given platform? what's recommended config for scheduling, queuing? is it recommended to leave scheduling, queuing to default value?

[vmiller]

Before you look at platform specific issues or techniques, you need to take a much more global look at what you are trying to accomplish.

this is a pretty good starting point:

http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND/QoS-SRND-Book/QoSIntro.html

[gavin han]

Thanks. I did review it.

can you advise where can i find platform specific best best practice CVD for QoS?

[vmiller]

I do not know of any platform specific best practice documents. Most of what i have used in the past is directed at QOS end to end and tends to be platform/operating system agnostic.

here is a link to the QOS doc wiki, another "overview" source.

 http://docwiki.cisco.com/wiki/Quality_of_Service_Networking

[gavin han]

Thanks. What's best practice for queuing and scheduling?

what needs to be considered while configuring QoS for VoIP (avaya voip)?

[gavin han]

anyone?

[Joseph W. Doherty]

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The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

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Posting

Cisco does have QoS SRNDs, that show recommended configuration for different device types.  E.g., http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND_40/QoSCampus_40.html

However, I wouldn't recommend following Cisco's QoS design guides, blindly.  Further, I believe Cisco's QoS design guide assumes you're using Cisco VoIP phones, which support CDP.  In principle, you'll treat traffic to/from your Avaya VoIP phones the same as if they were Cisco VoIP phones, buy the Avaya phones cannot trigger policies Cisco devices as can Cisco VoIP phones.

BTW, Cisco's QoS doesn't currently conform to RFC QoS, although its close.

At to best practice, QoS, "by the book", would be end-to-end, but you only really need (or just initially configure) QoS at congested interfaces where the congestion is adverse to your traffic needs and can actually be mitigated by QoS.

[gavin han]

Thanks very much for detailed info.

on ports where phones connect, should i put "auto qos trust cos" or "auto qos trust cos"?

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

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In no event shall Author be liable for any damages wha2tsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

I recall (?) those commands require CDP capable VoIP phones.  Additionally, I recommend basing QoS on ToS (L3) tags rather than CoS (L2) tags.

[gavin han]

Thanks. Avaya phones don't support cdp, they do lldp i think. so would "auto qos trust cos" or "auto qos trust cos" do the job? which command to use?

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

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In no event shall Author be liable for any damages wha2tsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Yes, I  believe, Avayas don't support CDP, but they do support LLDP.  Only later Cisco devices support LLDP, but those that do, I don't recall (?) Cisco supporting features like "auto QoS", using it.

[gavin han]

Thanks. would "auto qos trust dscp" trust dscp value coming from Avaya phone?

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages wha2tsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Again, I don't believe (any) "auto QoS . . . " will work with Avaya.

What you place on the port, depends on the device.  Older Cisco switches will pass QoS markings if QoS not globally enabled.  If QoS globally enabled, you need to trust the marking (or have an ingress policy that does).  Recent Cisco switches now work like Cisco routers, they pass QoS markings.