IP Telephony Solution

[reshmi_2005]

I need a IP telephony solution for 150 users. The network interconnects 3 locations. I am new to this field. So i am not clear whether i should go for router integrated IP solution or Independent Server based IP Telephony solution. The customer already has 1760 voice integrated router in each location. So if we go for router integrated IP Telephony solution,will it be costly. Please give me a good solution which is efficient and economical....Thanks in advance

[agopala]

reshmi, there are a couple of things you need to consider:

how many users do you have at each location? Does the main site have most of the users? What is the bandwidth you have between the sites. Are the sites connected with your own circuits? or is it owned by telco. In other words, can you make changes to the routers (think QOS)..

a 1760 is a fairly small router. It is the lowest that cisco positions as a voice GW. So, There is only so much you can do with it..

ANother thing you need to consider is if there are going to be a lot of inter-site calls. that determines the BW of the links you need. Next thing you need to determine is if you want calls to go out of their local sites. that will mean you need a T1 or a few FXO ports at the routers depending on the number of simultanious calls you need.

Let us assume you have 20 users in each site, and 100 users in the central site, then, you can have a call manager at the central site and that is all you will need. This will mean you need a lot of BW between the sites. If users just call their own site primarily, then, you do not have to worry about BW.

Go to http://www.cisco.com/go/srnd/

look at CCM 4.x SRND and QOS SRND. this will get you started.

[thisisshanky]

Reshmi,

You also need to look at what features you need for 150 users. Callmanager solution can scale up to 30000+ users where as Callmanager express is well fit for user under 240 users. Note that Callmanager is a replacement for a traditional PBX, while Callmanager express is a keysystem replacement. Based on the above, you may use CME or Callmanager for this solution. If cost is a factor, and some features can be sacrificed, you may use CME. For 150 users you may need to use a 3800 series router.

If you want all features of Callmanager you may propose a cheaper solution by using two 7815 servers(tower based, not rack mountable) and run Callmanager on it. 7815s cannot scale more than 300 users and you cannot cluster more than 2 servers. So you are limited to 300 users, and if the customer does not expect scalability in near future, this might be perfect fit.

HTH

Sankar

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