QOS on 3750x

[Robin Swan]

I am tasked with migrating our WAN from Microwave T1 multilinks (2 each endpoint), over to a fiber backbone.  We are getting 100Mb at each site with 1 fiber port from the provider.  My supervisor doesn't want to "re-invent the wheel" but wants to get rid of the routers.  As a result, we got 3750x switches with IP Services licenses and Universal IOS'.  We have QOS for Shoretel and Multicasting for analog 2-way radio's at each site.  Also, even though when I came onboard, EIGRP was already in place and we were requested to add OSPF. 

Whe I try to put the service policy on the outside of the uplink interface, I get this error:

"Warning: Assigning a policy map to the output side of an interface not supported"

How can I work around this?

[Joseph W. Doherty]

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Posting

The 3750 series doesn't use service polices for egress queuing like a router.  Instead it has 4 hardware egress queues.

Creating a 3750 QoS implementation isn't trival unless you activate autoQoS, and that assumes it meets your needs.

Unless you really understand 3750 QoS, often you're better off not enabling it at all because a 3750's queues are rather shallow, by default, when QoS is enabled.

[Robin Swan]

So does that mean that the phones won't be working?

[Robin Swan]

At this point, would it be strongly advisable to get TAC support for the configuration?

[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 whatsoever (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

Jay Swan wrote:
So does that mean that the phones won't be working?

Maybe, maybe not if you don't configure QoS to "protect" your VoIP traffic.  You can configure QoS on a 3750X, but it's "different" from software router QoS.

The user guide for the installed IOS will have a chapter about QoS features.  You'll also find additional whitepapers about 3750 QoS on Cisco's main site.