SIP trunking to XO

[acejavelin]

Anybody done XO eSIP trunks?

They are delivering use their trunks in kind of an odd way (to me at least), they won't use our MBG but instead delivered a Cisco 1941 router and with a LAN interface on the voice VLAN subnet, and said it needs to be the gateway to signal to their SIP server, which is XXX.XXX.XXX.30 with a caveat that says (Note: Customer should open the NBS Block  XXX.XXX.XXX.16/28. Doing so will account for the RTP IPs), and they will signal to the vMCD's private LAN IP.

So I need to set this up, is it common to build the router as an Outbound Proxy (like an MBG) in network elements and set it up pretty much the same as a SIP carrier through that proxy, or do I need to go into MSL and build a route that says for XXX.XXX.XXX.16/28 use the gateway of the LAN IP address of the Cisco router?

All the documentation on XO and Mitel's website (https://www.xo.com/sites/default/files/inline-files/10-4940-00105_3-XOCommunications_MiVB5.pdf) seems to dictate a MBG is used and it's signalling to a public IP in the cloud, but we had no way to implement that as this installation is in a data center and completely virtual, even the WAN of the MBG, but the carrier delivered us a router (and our MBG signals to several other SIP carriers in the cloud). 

I can't test it with the carrier until next Monday, but our implementation window is small, I would like to have these working as quickly after initial testing.

[johnp]

It should be fairly easy to send to the Cisco

[acejavelin]

It should be fairly easy to send to the Cisco

In theory perhaps, but according to the carrier it's just a dumb pass-thru router (a gateway) and we have no visibility into the router.

Guess I was just wondering if anyone else had done something similar... I have done lots of SIP trunking, but only a few configurations. MCD/MBG and signal to a SIP server in the cloud (most common), carrier delivers a circuit with an interface we connect to an MBG, or the carrier provides a router like an Edgemark or Adtran that sits with it's interface on the LAN and we signal to that router's IP address without an MBG (meaning their router acts as an SBC). Other than those 3 setups the only SIP I have done is completely internally between like a 3300 and a Digium or something like that.

Maybe I am being paranoid, but the setup they are giving me doesn't match their own documentation on interfacing with the Mitel, and when I try to wrap my around how it is going to work I see nothing but problems. Now, if the Cisco acts as an SBC or even a SIP-aware router, this may just be all in my head... But my experiences with this carrier in the past where changes need to occur is it takes weeks, so if they activate the service, we determine it doesn't work, it is basically back to the drawing board and this circuit is for a remote office to get DIDs that hasn't had them since December (when this was supposed be installed, but that is a different story). I am just trying to head off problems before they occur.