VOIP Help please

[mikeleahy]

Hi

my company want to implement voip soon. we have a mpls connection to another office with a ciso 2811 in each site. it works fine. how will the voip work,,,,, will the trafic be sent from the pabx to the router and then forwarded out to the loop and if so how do in conifigure the router to prioritise the traffic

 

[AJ1982]

If its Cisco VoIP you have an E1 card into a Router which then links into a Call Manager / Unity Server. Or you look for Call Manager Express/Unity Express if you have less than around 100-150 users.

If you have multiple sites, you need to consider reduancy if one sites PSTN goes down, or the MPLS link goes down etc.

AJ

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Fatman Superstar (Andrew James)

CCNA

 

[mikeleahy]

its two small offices about 25 people in each. how does the router get configured to prioritise the voice traffic

 

[AJ1982]

You need to use QoS, supported on the more superior version of IOS, if you have any support with the install they should be able to help you with this anyways...



===

Fatman Superstar (Andrew James)

CCNA

 

[UnaBomber]

my company want to implement voip soon. we have a mpls connection to another office with a ciso 2811 in each site. it works fine. how will the voip work,,,,, will the trafic be sent from the pabx to the router and then forwarded out to the loop and if so how do in conifigure the router to prioritise the traffic

It depends on what kind of cards you have in your pbx and how you want it to work.

I have implemented some Avaya solutions where we used fxs cards on the cisco router directly to an analogue port on the pbx. We have also implemented solutions using an IP card in the pbx which is connected to catalyst switches then to Routers. Both work.

As for QoS, if you have VoIP phones, ensure you have QoS implemented on the LAN segment, and VLAN off your phones from your data network.

On the WAN side you will need to arrange with your provider on how best to implement this, as they will have to 'trust' the QoS tags you implement on your router for you to have end to end QoS. Basically you need to align your diffserv (assuming that is what you will use) strategy with that of the teleco (or visa versa).

UnaBomber
ccnp mcse2k

 

[mikeleahy]

yes i understand what you say when you are on about the trusting of qos tags etc. so my isp should give me the details really.we are not going to have voip phones. how do i connect the router to the pbx

 

[UnaBomber]

What kind of PBX do you have, and does it have a IP card? if so you can just connect it via your layer 2 device that your router is connected to. If not, and you have analogue card on your pbx use a fxs card on your router. But beware, the cable you will have to use between the pbx and router will have to be correctly made, it probably wont be standard.

UnaBomber
ccnp mcse2k

 

[plshlpme]

as stated above you need to discuss with your provider how they do the qos..
usually we have the customer tag their own traffic with the proper precedence levels and we have policies that deal with the traffic accordingly...
your voice traffic needs to be in the low latency queue or NearRealTime class.

the rest of the MPLS network already has the QOS built into it.