I will be installing two Cisco 1921 Routers to connnect a T1 between two offices. We are changing out our current AdTran routers as we would like to bridge three VLAN's across the T1 link. I followed the instructions at
http://www.cisco.com/en/US/tech/tk389/tk815/technologies_tech_note09186a0080094663.shtml to the best of my ability and my two Gigabit Ethernet ports are tied into a bridged virtual interface (BVI1). I then assigned a IP to BVI1 and another to my Serial0/0/0 then made a route to get to the other side of the T1 and a defualt route out our proxy.
What I want to do now is setup QoS to make sure my voice data gets priority. I setup a QoS ACL called "Voice" with the TCP and UDP source and destination ports that our phone system uses. I then setup a QoS policy on the Serial0/0/0 outgoing interface called "VoiceTraffic" and under the "match" list I match DSCP 46 or my "Voice" access rule. For the action I turned on "Queuing" and set it up for LLQ at 50%. Does this sound about right? Is there anything els eI can setup? I tried ot setup something else on the ethernet side but because they have the BVI I can't. I read some article sin this forum that said I could still apply QoS to the GigabitEthernet ports even if they are in the bridge group but it doens't let me do that.
Any comments would be appreciated. Thanks,
EF stands for "express forwarding" and it's dscp value is 46, so the router converts it to EF.
if I am sending a 100Mb file up the T1 then I place a call the call will get the bandwidth and just subtract off of the bandwidth the file being sent is correct?
If you're uploading a file and the outgoing interface is congested, then yes, the current packet is completed sending and then the voice packets will be prioritized at that point. The problem comes in that even if you have qos, if you don't have enough bandwidth then no amount of qos will help.
It's not actually dedicating 50% of the line at all times...only when voice traffic is using it (things that match my ACL and DSCP 46).
Voice traffic coming through isn't what kicks off the policy. The interface needs to be saturated before the qos policy kicks in. So, yes, the 50% is only during the time of congestion because the llq also polices the traffic and doesn't allow more than 50% and it can go higher than that if congestion isn't present.