Remote Site Design - vMCD+vMBG or Daisy Chained vMBG

[bribob]

Assume that all systems are running the latest version of vMCD and vMBG. At the corporate offices there are two clustered vMBG blades, each with their own geographically dispersed public IP addresses. Within the corporate network are multiple vMCD/MCD gateways, also clustered, and all IP sets are configured for resiliency. A VPN exists between both sites. WAN connections at the corporate location are dual-homed and >100 Mbps.

The remote site has a single 6 Mbps (4xT1) WAN connection and the ISP is providing a 10 channel SIP trunk with E911 configured. The SIP trunk terminates at the remote site, with this in mind the SIP trunk will be terminating to the vMBG. The SIP trunk might be accessed by the IP sets at the corporate site(s). There are at most 15 IP sets at the remote site.

My thoughts were to install a vMCD at the remote site along with the vMBG, that way the IP sets retain dial tone in the event of a WAN failure at either the corporate or remote location. But without the WAN, there is no SIP. The IP sets turn into an intercom system.

Here are the questions:

Foregoing the vMCD and putting the vMBG into daisy chain mode, can the SIP trunk terminate on the remote vMBG and still provide the same call functionality as if there were a vMCD at the remote site?

I assume the audio path for external calls would be between the IP set and the vMBG, call control would still flow back to the corporate office.​

Would\should MoH stream from the corporate office if it's configured on the vMCD?

Does a daisy chained vMBG have any sort of resiliency towards the upstream vMBG? If IP A becomes unavailable and the vMBG cluster has IP A and IP B configured in the Resiliency tab, will the remote vMBG re-direct to IP B? Is the resiliency list only applicable to MiNet sets?

What other reasons, except for the Intercom feature or perhaps a SIP/analog gateway for 911, are there for putting a vMCD at the remote site? (A Line Interface Module could be installed on the main reception phone.)

If an IP set at the corporate office and remote office were to converse, the audio stream would route via the vMBG's at either site? If this statement is correct, this would simplify the need to route the remote voice subnet to all other remote subnets. Assuming that any remote IP set can reach the vMBG cluster, two way audio should be accomplished.

A bit of a ramble, I've been patching for the last 12 hours so any thoughts are appreciated.

Thanks,
-bribob

 

[LoopyLou]

Gee I usually say put in more detail. This is one case in that there is so much it becomes a chore to slog through it. I will answer what i think might be the questions.

Daisy chained MBGs do not have resiliency functionality. They are mostly used to simplify firewall programming. If you want resiliency then you would need a pair of clustered MBG's both with their own internet access.

I would think the remote vMBG would not need a remote vMCD to function as long as the necessary routing is in place. One of the features in the MBG is that it can be setup to take different numbers and send them to different MCD's. So for example in you have one set of SIP trunks to an MBG and if it is setup correctly, then when a Toronto number is received the MBG can route the call to the Toronto MCD. If a Vancouver number is received then the call can be directed to the MCD in Vancouver. All done across the LAN. Would think then that you don't need a MCD in the same place as a MBG as long as calls through the MBG can be routed to the correct location.

MOH would come from the MCD the SIP trunks are terminating on.

If two IP sets are talking and no trunk is involved then unless one is a teleworker there is no need for the MBG to be involved.




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