BCM400 Expansion Gateway

[mroberts]

I was wondering if anyone has seen or installed the new Expansion Gateway box that is supposed to expand the capacity of the BCM400 4.0.

From the docs, it looks like another BCM400 chassis with 48 VOIP trunks activated. Supposedly all the lines should go on the expansion side and all of the phones on the main BCM400. But it then also says that you can only put a maximum of two DTMs on the expansion side??

That doesn't make any sense to me. If I am going to do back to back BCMs via VOIP trunks then why not just do it and get all 8 buses out of each side. Unless they have made this "expansion gateway" much less expensive than just buying another BCM chassis, I don't see the point of it.

Anyone played with this yet?

Thanks
Melissa

MRoberts

http://www.a1teletronics.com

 

[biv343]

Played with it in a lab, it's not the nicest device out there. If you think of it as two separate networked systems, you'll see that management of it would be a nightmare if you had phones in both cabinets. Paging, voice call, etc won't work over IP trunks, so would want to keep all sets in one system and all trunks in another.

Two T-1's is the theortetical limit for PSTN connections anyway, unless you wanted to try to run master clock on a PSTN PRI/T1 connection. You could also throw analog stations in the expansion in an effort to keep your dialing plan somewhat consistent.

In a fully loaded scenario, you'd get 224 digital sets in the main system with all trunks in the expansion.

In my opinion, this is too hokey/risky. If you have a site that requires that many phones, they should be looking at a CS1000, not a BCM.

 

[mroberts]

That's what I was thinking. If you have two networked BCMs, have all the "lines" in one side and the phones on the main chassis, connected via VOIP trunks. Then why can't I have 6 buses for the "lines"? Three DTMs and some analog POTS lines for back up etc.

Then I could also use those virtual buses to connect IP sets to the secondary chassis and go out the lines on the expansion chassis.Or have them go through the VOIP trunks to get to extensions on the main chassis using a Coordinated Dialing Plan.

Have you tried something like that? I haven't gotten one yet to play with...

MRoberts

http://www.a1teletronics.com

 

[biv343]

You could load the "expansion" with three DTM's - issue is the clock source on the third. I don't believe that you can have three PSTN connected T1's in a BCM. I put three T-1's in a BCM once, one local PRI, a LD T-1 and a tie PRI to an Option 11. The tie T-1 had to be set to master for clocking. It worked, but not very efficient.

You could, theoretically, with a 3/5 DS30 split have 48 IP trunks, 5 loops for TDM and still put 80 IP sets on the expansion system. Might want to add a couple more PEC cards in that scenario.

So yes, it can be done, but you'll be wrestling with two different databases, centralized voicemail limitations (anyone on the expansion system loses their VM feature codes), inability to page over the IP trunks, etc.

 

[mroberts]

I've done the three DTMs fine. One is primary and the others had to be set to Master. It wouldn't let me do secondary but it worked fine.

Technically on a 3/5 split you can only have 90 IP anythings be they trunks or sets. If you have three virtual buses with 32 signaling channels each, subtract out the 6 channels that are for Mega D channel, Paging, MOH etc. You will end up with 90 signaling channels. The signaling channels are always 'on'. So they do not fluctuate like the Media channels, Voice bus or DSPs. And, yes, of course you'll need the extra two PEC cards.

But centrailized vmail isn't that big of a deal, you can just give them an Autodial of the first port of the vmail of the other side. They just log in slightly differently. I don't run into the paging issue much in that scenario anyway.

I really want one so that I can test whether the rest of the buses are there for use. The documentation on the expansion suggests you can't do anything other than the two DTMs which is hokey.

MRoberts

http://www.a1teletronics.com

 

[mroberts]

When you purchased the Expansion Gateway, did it come with any documentation?

Thanks
Melissa

MRoberts

http://www.a1teletronics.com

 

[biv343]

Yup - it comes with the BCM documents. Nothing special.

 

[acewarlock]

Is the BCM400 Expansion Gateway different than the Expansion box for the BCM 1000 and 400 before the 4.0?

 

[biv343]

Essentially it's another BCM that comes bundled with a bunch of IP trunks - kind of a cheesy way to expand capacity on a BCM. It is different than the expansion cabinet that connects to the DS-256 connector on the MSC on a BCM 400/1000.

 

[acewarlock]

Thanks for the info