Qos for VoIP

[j.baez]

HI

We have a cisco 1751 connected to internet and on the LAN a device of net2phone, to do calls through the internet. ¿It is possible to do some configuration in the router to reserve wide of band and to give him QoS al traffic of voice of this device.?

[ndoshi]

Hi ,

You can confiugure LLQ .

http://www.cisco.com/en/US/tech/tk652/tk701/technologies_configuration_example09186a0080101210.shtml

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a00800a954d.shtml

Nilesh

[tepatel]

Need to know what kind of link with encapsulation is there which connects to internet. Based on that encapsulation and the bandwidth of the link, we can tune the QoS to prioritize the voice traffic.

Here is the link which talks about per-call bandwidth required

http://www.cisco.com/warp/public/788/pkt-voice-general/bwidth_consume.html

Here is the link which discuss QoS for various links with different encapsulation

http://www.cisco.com/univercd/cc/td/doc/cisintwk/intsolns/qossol/qosvoip.htm

[j.baez]

The link is access to internet dedicated 128kbps, with encapsulation PPP, as mentioning is for voice on internet of the service provider Net2Phone.

thanks you.

[tepatel]

Here is the link which explains how to configure QoS over low bandwidth PPP link

http://www.cisco.com/warp/public/788/voice-qos/voip-mlppp.html

[j.baez]

I have some questions al respect.

The configurations of VoIP, with ppp multilink I know them well, my doubt is as implementing a configuración of this type that is connected to an ISP;the team of the ISP to have a similar configuration?, the plan of conexion that have is the following:

net2phone-----|---router------(ISP Internet).

| LAN

telephone

[kirkster]

That depends on whether your ISP will take any notice of your prioritisation scheme. You may prioritise the traffic that YOU send to THEM (i.e. your voip samples). However, on the return leg of the call, where the ISP is sending the far end speaker's voice to YOU, they may not be applying an equivalent service policy in that direction. This could lead to you missing words etc of the far end speaker.

This is a common problem when using VOIP to the internet. Even if the ISP does implement your policy, you may have to apply fragmentation and interleaving on your low speed serial link. Make sure your ISP supports this - it is often a chargeable option.

Steve