VoIP QOS over Point to Point

[dgrizzard]

At one of our offices I'll be putting in VoIP phones(nortel i series) and I'm going to setup the router for QoS over the PTP connection. Here is what I have for if it was a frame-relay connection, how can I translate this to PTP, and is using LLQ the best for PTP(using it for frame relay since FR strips off other QoS methods). Here is the config for QoS...

class-map voice-signaling
match access-group 103
class-map voice-traffic
match access-group 102
!
!
policy-map voice-policy
class voice-traffic
priority 300
class voice-signaling
bandwidth 8
class class-default
fair-queue

map-class frame-relay VoIPovFR
no frame-relay adaptive-shaping
frame-relay cir 768000
frame-relay bc 7680
frame-relay be 0
frame-relay mincir 768000
frame-relay fair-queue
frame-relay fragment 1000
access-list 102 permit udp any any range 16384 32767
access-list 103 permit tcp any eq 1720 any
access-list 103 permit tcp any any eq 1720
access-list 103 permit ip 192.9.180.0 0.0.0.255 any


Please let me know what you think, TIA!

 

[jneiberger]

Apply that same QoS policy to your point-to-point link and you'll be fine, at least as far as QoS goes. Since it isn't frame relay, you don't need to worry about the FRTS portion of the config. In fact, you won't need to worry about traffic shaping--most likely, anyway--since you don't have the queueing issues within the frame relay cloud to worry about.

What is the speed of your new link?

 

[dgrizzard]

It will be a full T1...will I need to worry about bursting or is it generally not an issue on PTP T1s? Also, here is my config for the serial connection..where it says multipoint what should I put to make it PTP? And under the timeslots is that correct? TIA

interface Serial0
description SouthBrandon PT Circuit
no ip address
no shutdown
service-policy output voice-policy
service-module t1 timeslots 1-24
!
interface Serial0.1 multipoint
description link to Telecom
ip address 192.9.228.180 255.255.255.0
ip directed-broadcast
service-policy output voice-policy

 

[jneiberger]

Your new config would look something like this:

interface Serial0
description SouthBrandon PT Circuit
ip address 192.9.228.180 255.255.255.0
no shutdown
service-policy output voice-policy
service-module t1 timeslots 1-24

There is no such thing as a multipoint point-to-point interface and there is no reason to attempt to use subinterfaces here. So, simply remove the subinterfaces and place all of your configuration directly on the major interface.

Your timeslot config is correct if you have a full T-1. You don't need to worry about bursting because there is no CIR to burst over. As long as you have solid QoS in place to ensure that your voice traffic is prioritized over other traffic, you should not have to even bother with traffic shaping.

 

[dgrizzard]

Looks good thanks alot!

 

[dgrizzard]

With the above config, will I need to specify encapsulation ppp since this is a PTP T1? Also there is a no fair queue setting that won't go away.

TIA

 

[jneiberger]

Yes, you need to specify the correct encapsulation type. Don't worry about the fair queue stuff. Fair queueing needs to be turned off in order to apply the service policy, and the "no fair-queue" line simply indicates that it is turned off.