Channelized T1

[Lancbar]

I have a question about channelized T1. Can you group individual channels into larger individual groups.

Example:

1 channel = to 64 kb
4 channels = to 256 Kb
8 channels = to 512
.
.
23 channels 1.544 Mb

The question is, is this possible and what situation would this be used for. Is it typical to see a a channelized t1 with 4 active channels and the rest disabled.

Are there any good links on cisco that explains this in greater detail, configuration examples especially etc.

Thanks in advance

 

[CCIEWANNABE]

You determine how many phone lines out of the T you will need, and how many lines to dedicate to Internet access. You pay a port charge on the Internet speed you select.

http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/dial_c/dcchant.htm

Route once; switch many

 

[Guest_imported]

What do you mean by "Phonelines". Phonelines is not the proper terminology. Channels. It is common for people to get fractional T1's, like 4 channels of 64k resulting in 256k.

 

[CCIEWANNABE]

Take the usual 24 lines in a T-1 and assign each line as voice or data lines according to your needs. All you need is a standard CSU/DSU and an office router. You can combine lines or channels in increments of 64K for your dedicated internet connection. easy to set up Try Cisco or

http://www.netopia.com

and here is very good educational link about T lines.

http://www.dcbnet.com/notes/9611t1.html

"Clearly the intended use of T1 was to bring in as many telephone lines using voice as possible through a digitized technique" quote


Route once; switch many

 

[tadiman]

What your talking about is done frequently. There are several good reasons to do this. First these channels are "bonded" to make the bigger bandwith pipe. This pipe than can be used for internet, frame relay, ppp or just about anything depending on the equipment you install.

A very common use is "drop and insert". This is where part of the T1 is used for data 1 to 23 channels and the remainder is used for dedicated voice services. The service provider needs to support this feature. It runs through a piece of equipment called a DACS at the provider end. On your end equipment like Adtran's TSU series would be used to break this back out. LD companies will charge you by port size on the bonded data pipe but the remaining channels they will generally fill with voice for no additional charge, they make the money on the per minute voice. The rate on this dedicated voice is then 20 to 70 percent cheaper than "switched" (POTS) rates.

There are many variables involved in evaluating which equipment to use.

And I have already seen a T1 access put in and only 2 channels (128k) used for data.

 

[Lancbar]

Great information. Thanks for answering my questions.