atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's T1 Configuration for IP Phones

I'm installing IP phones on a LAN fed by 2 T1s. One is configured(provisioned?) as 24 data channels and one is an integrated T1 w 14 bundled voice lines and the rest data.

I am uncertain which configuration to use for IP phones- a channelized config or must it be one big pipe?

How about PRI? Can PRI(or should I say B channels) support IP phones?

PRIs and B channels have nothing to do with IP phones except to provide a voice path to the carrier. You can have 50 IP phones and no lines T1 or PRI if you want a large network based intercom.

I agree with what RBF said but I also think we are missing some info.

Can you tell us if this is a hosted PBX application? As in, no PBX at the customer prem? If so, you'll want the largest "data" pipe you can get and close attention paid to QOS. If it's not a hosted pbx solution like Cisco Call Manager, you can have PRIs go right into the IP/PBX and the phones only use a local network for IP connectivity so bandwidth is a plenty and you setup a VLAN for the phones.

I also need to know why they have a full T1 for data and another router with fractional data? We might need to get a better idea of the hardware/CPEs just to understand better. Perhaps they have to separate connections for redundancy or they use one pipe for some type of dedicated server application?

Also, how many phones are you installing and what voice codec are you using? Compression will be a factor in deciding how much bandwidth you need to make available. Of course, this is only a big deal if you are using a hosted pbx solution.

Fred

Here's the full story. First, let me say that I have relatively little experience with T1s, and never installed T1 hardware with a system. I have always programmed PBX switches and now am installing key systems for small businesses. This is my first medium business-sized Norstar install, a BCM 400 with 20 IP phones onsite and 6 IP phone across the street which is connected to the network by a cat 5e cable. I realize I need help, and intend to hire some. Meanwhile, I am trying to get a full picture before the install gets moving along.
The existing key system is a Toshiba which uses an XO integrated T1 bringing in 14 analog circuits to the key system along with 10 data channels remaining. A new T1 was ordered for increasing bandwidth on the data network, and configured for 24 data channels by the network guys from a remote site. Now customer has decided he wants the new T1 to support the new IP phones.

Am I understanding correctly that I should maybe use the analog circuits in the T1 rather than the T1 w 24 data channels? I believe XO also offers DIDs in some deal, but I would like to use what exists.

On a BCM I would do a PRI and get at least 20 DIDs. Setup all of your target lines 1st then worry about how you are going to use them later. As stated IP phones have nothing to do with how you provision the WAN. Your Toshiba most likely had an RDTU as it card, you will use a DTI card on the BCM. I propably still have a cheat sheet for the BCM if you need one.

To reconfigure the T1 for DIDs , XO wants 6 weeks. If we use the current configuration, the BCM can be installed now.

6 weeks is absurd. Kick some ass and take some names. Geez. It shouldn't take anyone with half a brain to reconfigure a TDM trunk as a PRI and route DIDs. Anyone disagree? Mind you I'm not a switch tech but I've seen changes like this done in 15 minutes or less with the right person behind the wheel. (AnthonyH?)

As for adding another data T1 for IP phones...I'd say that based on what I have read above, the PBX is a VoIP pbx with all traffic being handled over the local area network (on a VLAN perhaps?) and you wont be doing offsite IP phones? If that's the case, there wouldn't be a need to beef up your Internet connectivity. Do we know if they plan to do offsite VoIP as of right now? If you do end up bringing in another data T1, do you have a plan in place to share the bandwidth between those data T1s? Are they both going to be from the same carrier? If so, you'll have a choice of MLPPP or Cisco CEF Per Packet or Per Destination load balancing. If you are doing VoIP or QOS on the Internet T1s you'll probably want to stay away from per packet.

6 weeks seems a bit long, they are basically just making you reorder a new ckt, and have the whole thing start from scratch. If they already have the facilites reserved for the T1 they should be able to set this up as a PRI failry easy. You should see if they can expidite a conversion for you, Most of teh VOIP systems that I see are running across PRI's.

But what about the current T1 configuration?

1. Can the BCM 400 with IP phones use a GATM8 card with the integrated T1 bringing in 14 analog lines?

2. Can the BCM 400 with IP phones use a T1 with 24 data channels? I don't see where the dial tone would come from.

jjimm,
How much exposure have you had to the BCM-400 system? In requesting to have 26 IP phones installed, why is your client pursuing the BCM 400 instead of the BCM 200? Is the client wanting to completely replace their current Toshiba system, or are they simply wanting to add the 26 IP phones to their current architecture? The BCM 400 supports 30 to 200 users. However, the BCM 200 supports 20 to 32 users.