Goal

Nortel MCS5100 can only accept external SIP calls from domains that are statically entered into the configuration. If the end-users that are registered at the MCS want to call 'outside', or want to be reached from outside, this recipe can make it possible using Asterisk as a SIP Border Controller (SBC).

The call scenario involves the following nodes:

UA A    ->    MCS5100    ->    SBC    ->    proxy domainB    ->    UA B

Calling from the MCS domain to the outside world requires a trick, namely

if you're using UA A and you want to call user B with address

userB@domainB.net,

you must type into the Nortel MultiMedia PC client softclient the following address

userB_domainB.net@sbc.domainA.net

so the original '@' must be replaced by an underscore, and the new URI must be followed by the domain that corresponds with the SBC, so that the MCS can forward it to the SBC.