Ben
Guest
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Posted:
Thu Dec 16, 2004 7:15 pm Post subject:
Re: need help getting started w/ QoS |
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bruce wrote:
| Quote: | We're just starting to test IP phones at a couple of our remote
offices. Our phone equipment is all Nortel. Our LAN switches are all
Cisco.
My initial searches on Cisco VLANs and QoS have turned up a seemingly
endless amount of reading on this. I'm hoping someone w/ experience can
narrow down my options.
I've created a couple of port-based VLANs on a 2950 - one for pc data,
one for voice data, and trunk those to a PIX 506. What is the best
method to ensure that traffic from the voice data VLAN has a higher
priority on the trunk port of the 2950, and on the PIX?
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Basically you need configure a priority queue on the trunk link.
This assumes that your voice traffic is already marked to a higher CoS
(layer 2)/DSCP (layer 3) than your data traffic as it comes into the
switch. I am not familiar with Nortel phones but Cisco IP phones do this
by default. All phone ports should be set to TRUST incoming markings.
All data ports should be set to NOT trust incoming markings and remark
to a default Cos/DSCP.
The end result is your voice traffic will get real-time service and
always get served before data packets if they are waiting in line.
On the pix side it shouldn't be necessary to do anything for traffic
inbound from the switch.
Outbound from the pix it depends a lot on the rest of your network. In
general if you have a qos-enabled network you should be marking
everything to default qos at the edge, except where you can be sure
existing markings can be trusted. Assuming your network is delivering
traffic with reliable markings to the pix, then a similar setup on the
PIX is needed.
I have no idea of the pix qos features, but, if it's similar to IOS, you
again need to use the modular qos interface (MQC) to create a policy-map
with a priority queue. |
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