PVDM

[bahman.tajkarimi]

Hello guys,

I have two gateways one for data (WAN) and one for voice (PSTN). Do I need to install and configure the DSP in both gateways or only in voice gateway would be enough?

Thanks,

[ananddiwakar]

If you are not connecting to any other CCM cluster using your data link, you do not need any DSPs in data router. DSPs in voice gateways will take care of your PRIs, conferencing etc

[bahman.tajkarimi]

The publisher will be installed in HQ and the Subscriber in another site (50 miles distance). Is this considered as two different clusters. Would the configuration for PVDM in data gateway be different than the one in Voice Gateway.

Is PVDM (DSP) used only for conferencing?

Thanks for taking the time and responding.

[fred.s.mollenkopf]

The Pub and Sub are part of one cluster. If you installed a 2nd Pub then that would be a second cluster. Clusters don't share any data between them and are connected via trunks with route patterns route callers between the two. You shouldn't need a 2nd cluster. Thing to remember though is intra-cluster communication has a round-trip latency of no more than 40ms in CM 4.x. If you are going to surpase this then you would need a 2nd cluster.

A PVDM is a module that contains DSPs. The data router has no need for the PVDM unless you want to terminate voice on it. DSPs are used to for voice calls, conference, transcoding and media termination points.

Please rate any helpful posts

Thanks

Fred

[bahman.tajkarimi]

Thanks Fred,

In my case, I have a Pub in the HQ and a Sub in the Disaster Recovery Center. Would it be considered one cluster even if they are distanced about 50 miles and are in different subnet?

When we call inter offices by dialing 4 digites don't we use the date gateway(WAN)? In the case of having a conference call between three offices, do we need a PVDM installed in the data gateway?

Thanks

[thisisshanky]

Your deployment model follows the clustering over wan model.No matter how far they are, the pub and sub are part of the same cluster.

When you dial 4 digits, it will use the wan to send the call. Depending on your region configs, your calls will use g711 (80kbps) or g729(24kbps). To reduce the bandwidth utilisation, each office can be put in a separate region and then use g729 between them.

In this case its recommend that you configure a hardware conference bridge /transcoder for conferencing and transcoding purposes. This will require DSPs

HTH

Sankar

PS: please remember to rate all posts!

[fred.s.mollenkopf]

Bahman,

Like Sankar said clustering is not based on distance or IP topology. It is based on how Call Manager is installed and configured. The thing to remember if you are using both CallManager servers (meaning you have devices registered to both) then you shouldn't go above that 40ms restriction.

Your voice gateway should be the logical choice for DSP hardware conferencing. This is because the IOS code needs to support voice and you might not want to run voice code on your data router. But the key to remember is if you have users local to a site that doesn't have a CCM you should definitely look at having IOS hardware conferencing (DSP) for that site. That way you won't have conference calls going over the WAN for local participants.

Lastly if you take Sankars recommendations you will probably need DSP resources for Transcoding. Using G729 can save you a lot of bandwidth and is not noticeable to the users if deployed correctly so you should definitely read up on that.

Please rate any helpful posts

Thanks

Fred