IP phone expertise please help

[joeban]

Hi All
I have been asked by my boss to look into the ip phones as solution for our remote offices.we use the internet throuh VPN to connect to those remote sites.Do any of you be kind and share his experience with this prodduct.Our swith is capable of handling the ip phone and we have 10 pepole connected on the lan using them. The issue with the remote offices is that the bandwith is low since.My question is what kind of compression you using and how will the ip phone measure up?. any gotsha should I woory about.
thanks for your help

 

[T1PSTN]

Just how much bandwidth do you have to the remote sites? Will IP voice traffic have to contend with IP data traffic?
Ip telephony is a very flexible solution, overall. Which brand are you interested in deploying?

 

[joeban]

Thanks for the reply.
the connection is through the internet with hub consists of 3meg and the hub of a 1meg each. those sites uses vpn to recreach each other and yes the ip voice traffic has to contend with ip data.

 

[Arr]

I did a Norstar VOIP extention to a sub office using MCK. Over internet, there was a 40K per station bandwidth usage. I used ISDN on which the MCK used 16K bandwidth and it worked perfectly. MCK makes several single line set extenders and a mobile extender (but I'm not sure if it works on M1s).

PhM

 

[T1PSTN]

Sounds like you've got enough bandwidth to make it work great. You will have to make sure that QoS policies are properly set up at each of the endpoints to ensure that the voice packets take priority over the data packets. A half-second delay when receiving an email is OK, a quarter-second delay during a conversation is going to drive the end users crazy.

 

[joeban]

Thanks
I have another question. we use the itg2 line card.we have a remote site that uses 56k. will the ip phones works over the internet with a direct VPN ?. Can I use a compression 8K on a port while getting diffrent compression on another port on the same ITG2 card ? or each ITG2 card has all port on the same compression that you cannot change?. Do this setup works. Thanks for your input.

 

[Reusser]

Yes - you can set individual phones with different compression that register to the same card. a call from a phone using 56k to a phone with 8k compression the call will always chose the 8k compression.

 

[joeban]

is there a place where you go to set the 8k compression versus the default which is 56k for a prticular phone.
Thanks for you help

 

[Reusser]

In OTM - Open up the ITG node - select the DSP tab - select the CODEC tab. make sure there is a check on G.729AB.

In LD 117 print zones find one with BB (best bandwidth)

make sure this zone is setup for ITG line ports (tie trunks) and ITG phone sets.

 

[joeban]

Thanks Reusser
the way you explained how to diffrenciate whether this extension is using the 56k and another one is using t 8k compression?. I have only 1 ITG card. so I haveto reserve x number og tie trunks as a 8 k and the phone sets?
thanks for your reply