Direct Media Path: yes or no?

[tmckeown]

Hi,
I have an SCN with two sites. One in Chicago and the other in LA. I also have a number of IP phones (5610) in managments homes. All the phones connect via ipsec tunnels back to the hub which is in Chicago. I've recently been running into trouble with IP phone callers not being able to hear a call they place. I know it stems from routing issues and the fact that we are using direct media path for all our voip connections. If we dial an extension between two spokes (ip phone to LA office) the callers can not hear each other. If we intercom between spokes, they can hear fine. I know that intercom forces the connection to not use direct media path. I'm having trouble with our current firewalls in getting them to route correctly for use of direct media path.

What is the down side to turning off direct media path? Is there a recommended practice? How much does direct media path reduce the network load? How much of a hit do we take by turning it off?

Thanks for the help,

 

[janni78]

Direct media path is usefull if you have calls from IP-to-IP or over several systems, this would make the calls connect directly to closest destination and save VCM channels.
The problem is that you have to know how to build your network routing tables.
Most problems usually occurs for home users cause everyone has to know how to route to that destination.
Sitting down and drawing a network map would give you an idea of what routes you should be aware of.

 

[tmckeown]

Thanks for the reply. I did setup routes on all the routers to direct traffic to all the spokes in the system. Spoke to hub works fine. Spoke to spoke is the problem. It's funny, but before I installed the second IPO in LA, all the spokes could talk to each other. I'm not really sure why it stopped functioning, though the type of routing I'm doing is not technically supported by Watchguard on the firewall/routers.

If I have the VCM channels to handle the traffic, will it increase netwok bandwidth needs by disabling Direct Media Path?

Thanks,

 

[janni78]

It depends how your network is configured today.

If it already goes that same way it would without Direct Media Path the bandwidth needs would be the same.

The point of Direct Media Path is that the calls can go the shortest way and talk to each other directly and save packet transport time, jumps and bandwidth, but this requires that the routing allows it.

 

[tmckeown]

Thanks,
That helps explain it a bit better. I'm going to double check my routes to make sure I can ping all the subnets.

 

[janni78]

You being able to ping all subnets is not a guarantee that DMP will work. Each unit must with their settings be able to ping their destination.
What you must think about is, what does this unit require to be able to reach all it's possible destinations and vice versa.