Transitioning away from ATM

We have 3 or 4 older sites that connect back to our central site using ATM over 2 T1s. This connection is for both voice and data. Equipment is a 3640router and 8510 switch. These are our last sites on ATM, and we'd like to move them away from ATM as soon as we can.

Looking at the Cisco documentation, it looks like we could use 3925s at thecentral site and at each of the remote locations, with VWIC3 cards (we're using VWIC first generation cards now in the 3640s), and use the drop and insert capability to handle voice and data. I had done some setups like thisat a previous job... it's been a couple of years, but hopefully I still got the concept. If I've got this correct, what do we need for the connectionto the phone system?

 

Hmmm, I don;t know much about

I haven't used T1, as we only have E's in ZA (E1 etc), but here you would require a Channelised E1 to achieve what you are doing for the data. Mixing both should be attainable, and being a VWIC card I would imagine you could use the card for Voice too. Just, not 100% of the setup. Probably not that helpful in hindsight. You can always try the forums. Either Cisco Forums themselves, or #cisco on freenode. Good luck.

 

MMmmm. 8510 switch. That brings back memories..

The docs say the VWIC3 all support DI with any number of tdm-groups as
you need. You'd take your inputs from your leaf sites and do whatever
feeding of the phone system all with VWIC3 ports. Thus if you have say
8 T1 ports used on your 8510 switch, you'd need 8 ports of VWIC3 T1s
of whatever density you want (ie. 1, 2 or 4 port VWIC3 cards).

Then setup the tdm-groups to xconn your DS0s from whichever T1 to
whichever T1 as you need setup.

If you need to do PRI switching, then you'd need something else than
the 3925 (or Cisco really, more like an Adtran Atlas), but doing DS0s
and tdm-group DI switching should be totally doable with the VWIC3
cards and the cisco platform.

At your leaf sites, you'd again break out things with VWIC3 ports,
one or two in, one or two out to the local phone system. Configure
your channel-groups for your data access. Configure your tdm-groups
for your voice DS0s.

 

Thanks to everyone for their replies to my thread. It will definitely help.If we didn't go with the drop and insert idea, what would be your recommendation for routers, both central and remote site, to use 2 point-to-point T1s per site and have the routers do all of the VOIP? It would probably be about 800k for voice and the rest data.

 

In many ways, Drop & Insert are easier to engineer and implement.

The same class of routers you already asked about would be useful for
VoIP as well. Any of the ISR G2s (ie. 19xx/29xx/39xx) depending on
port density required.

If you need to feed phone systems, you'll still the VWIC T1 cards to
interface one for each T1 port you have. You need to make sure you
have enough DSP timeslots bundled in (most likely the base amounts
will be fine for your VoIP needs).

VoIP brings in QoS needs and the like as well to reserve the bandwidth
needed instead of carving up T1s into port groups and tdm-groups.

Where VoIP can help you though in a scenario where you are aren't
dragging T1s long distance just to have voice-channels. You can use
whatever reasonable IP service is available at that site as long as it
is stable enough and has enough bandwidth.

On the internal facing side to the phone systems, everything is the
same as the D&I setup.