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cooldude9919

join:2000-05-29
kudos:5

TDM - VOIP - TDM With NM-HDV?

We have a voice MPLS network using new NEC IPS VOIP capable switches. We have some older NEC phone swithches at some remote locations that cant do VOIP and it would cost ~30k for a new phone switch. They can do TDM PTP links, but it is cost prohibitive for a ptp t1 due to distance.

I have seen some boxes made by rad,overture, ect that can do TDM over IP. We are a cisco network so i am looking into options for doing something like this with cisco. We have cisco 2811's at each site.

From my research it looks like a cisco NM-HDV-1t1-12 (or 24, or 2t1-24, ect) should be able to do this. Anyone have any comments on this? Also if so anyone have any configuration examples? I have looked but havent had much luck finding stuff so far. basically i just want to the router to be as seamless as possiblein the process, the nec switches on both ends will take care of the calls and everything, i just need to go from TDM to VOIP and back to TDM again.

I can get these used for $200-$300 each, where as the option with RAD would cost $2500 each.

nosx

join:2004-12-27
00000
kudos:5
The feature it sounds like you want is Circuit Emulation over IP (CEoIP) for transporting TDM over IP. You will probablly need a NM-CEM-4TE1. I dont think those VWICs can actually do raw TDM over IP. Also keep in mind that a T1 encapsulated over IP chews almost 2meg with CEoIP gear due to protocol overhead.

cooldude9919

join:2000-05-29
kudos:5
I had actually seen that card as well, but there arent many out there, and the ones that are are VERY expensive (3-4k on ebay).

I had some of your same concerns, and the documentation isnt very clear, but some of the points seem to lean towards it doing what i want, but like you im not sure.

nosx

join:2004-12-27
00000
kudos:5
I have done what you want with cross-connected VWICs but it required a protocol to be running for data like ppp hdlc or frame relay.

My understanding is that if you want true TDM level signaling you need the CEM NM, and yes they are very expensive.