QOS VOIP - Hosted IP PBX Provider

Bill,

If your T1 used not only for telephony, then you definitely need to configure QoS on the router, as well as on your switches, as well as confirm the configuration on the provider side. Here is a great document on all aspects of QoS on Cisco devices (it's "best practices" for Quality of Service).

In general, you must configure QoS on all your devices - the router, LAN switches, phones. For example, if you configured QoS on the router, but your LAN switch strips QoS marking, your QoS will not work. Or if your phone sends other information, than router expects. Here is a list of what you should do:

1. On the Router configure Priority Queuing (page 185)
2. On the Router configure Traffic Shaping for the voice (pages 206-215) based on number of calls you expect.
3. On the switch(es) configure CoS trust (pick the section in the menu depending on model of your switch)
4. Confirm with the provider, what DSCP values do they expect.

Also, since you have a firewall between your LAN and the router, things may become more complicated, since firewalls (except the latest code of Cisco ASA) do not understand and do not conform the QoS settings. So, you may need to re-classify all voice traffic at the router.

Also, if you don't feel comfortable with doing all this stuff yourself, I would advice you to get a consultant, who will do all this changes for you. Believe me, it will be faster and cheaper.

Good luck,

Mike CCNP, CCDP, CCSP, CCVP, MCSE W2K, MCSE+I, Security+, etc. CCIE R&S (in progress), CCIE Voice (in progress)

------ Headset Adapters for Cisco IP Phones

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Mike,

Thank you for your suggestion. Do you have a URL or the author of the mentioned doc - "Here is a great document on all aspects of QoS on Cisco devices (it's "best practices" for Quality of Service). "

Thanks!

Bill

Sorry, forgot to insert the URL:

Mike CCNP, CCDP, CCSP, CCVP, MCSE W2K, MCSE+I, Security+, etc. CCIE R&S (in progress), CCIE Voice (in progress)

------ Headset Adapters for Cisco IP Ph>> Bill,

snipped-for-privacy@gmail.com wrote: : Hi,

: Cisco 1720 router with 1 internet T1 to a IP PBX hosted provider. : I am having constant dropped calls, choppy, echoes, backup noises and : clipped calls when using the IP phone. I would like to implement QOS : on router, and am wondering if this will help.

Don't forget -- QOS on your 1720 only queues things on the egress of your network. Your provider has to provide queuing for the ingress.

A better solution is to buy a bigger pipe, but that isn't always an economical solution.

I sell a hosted PBX product. We try to make sure we also sell the Internet access so that we can control packet flow to the customer premise. It helps us eliminate a number of the quality issues that other hosted companies run into.

We also keep all of our VOIP gear in a single /24, so that customers can prioritize packets in our direction based on IP address. A lot of cheap equipment allows you to priority-queue things based on IP addresses. (Actiontec ADSL equipment comes to mind...)

An old-school Cisco template for priority queueing would look like: ! interface Serial0 priority-group 1 ! access-list 112 permit ip any ! priority-list 1 protocol ip high list 112

This template is likely to work on your 1720 -- but doesn't use the newer modular QOS mechanisms, so is likely to draw ire from many directions.