Panoramisk / The VoIP druid 

From version 1.4.4 and revision 69775 the call-limit parameter on a SIP trunk is taken into account.

Maybe have you tried to limit call number on a SIP peer without success, effectivelly the parameter call-limit was not checked, more precisely the number of calls was not updated. This was working for a telephone but not for a peer.

In the sip.conf file, you can use such configuration:

[trunk-test-test2]
type=peer
host=asterisk-test2
qualify=50
context=from-asterisk-test2
username=trunk-test-test2
md5secret=cee0374044a6c33313e1723c79203ad8
call-limit=5

In order to check the current amount of calls, you can issue the command sip show inuse, the result for the above peer with one engaged call is:

* Peer name               In use          Limit
trunk-test-test2          1/0             5

Hope this helps.