One way issue to remote site

[visualspirit]

We have a 3300 at a site which has an MBG for connecting the SIP trunks. Everything is fine and all phones work well on this site.

They now want to put phones connected to this system at a remote site a few miles away. There is a strong 100/100 Mbps short haul data link between the two.

I have been there and tested a phone and all works fine on making internal calls, however there is one way conversation on external calls.

The called party can hear me but I cannot hear them. I cannot hear the ring signal either.

I suspect that it's an issue with the MBG not knowing the route back to the remote site, however the two guys in our office who are fully trained with the MBG seem to think not.

The link between the sites have no internal firewalls and the 3300 can ping the gateway and phone at the remote site. Hence the reason internal calls can be made.

Any ideas anyone?

[acejavelin]

I guess I am confused here, are these phones going through the MBG or connected to a VPN or a routed connection of some kind? You say you have some kind of "short haul data link" between the two sites, is this a metro WAN link of some kind?

If there is no NAT translation between the phones and 3300, just a routed connection in private LAN space, there is no need for the MBG at all. MGB sits on the network edge to handle NAT translation to the 3300 from the public internet and is intended for phones coming in from the public internet, not phones on a routed connection back to the network.

Either way, the MBG is working properly for SIP, is likely not the cause of any audio issues in this, but you can run the MBG Teleworker testing tool (available inside the TW blade or server for download) to make sure all ports are properly translated.

[visualspirit]

It's a direct connection between the 2 sites. At the end of each connection there is a Cisco router and both are transparent.

I'm not too sure why, but we have to use a MBG to connect to our SIP provider Gamma.

I'll try the TW tool tomorrow.

Thanks.

[x-man]

Is it  a VPN?

[ralph]

Look in your MBG and be sure the new remote network is listed in the local network section of the main menu.

Ralph