Channeled and unframed e1 or t1

Unanswered Question
Apr 17th, 2007

hi there. in e1 or t1 what is channeled and unframed/framed. are they different thing? is it true if the e1 is channeled that it must be framed? please let me know... :) tx

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pciaccio Tue, 04/17/2007 - 03:58

When a circuit is channelized, it means that the line (Say a T-1) is broken down to 24 DS0's. So for the one T-1 you can have 24 64k or 56k individual circuits (dependant upon your framing type) riding on that T-1. If the circuit is unchannelized, then the T-1 has one circuit at either 1344k (if Nx56) or 1536k (If Nx64). When speaking about framing. A T-1 can be framed or unframed. If framed then the T-1 will add a framing bit every 193bits for every 125us. That means that your T-1 has a total DTE speed of 1536k(Nx64k)or 1344k(Nx56k) and with 8k of framing adds to 1544k which is the total bandwidth for a T-1. If no framing then the T-1 is actually 1536k total . Framing is used for the intermediate equipment that drives the line. It provides syncronization forthe line. You can have D4(superframing) or ESF(Extended Superframing). These types of framing differ dependant upon applications that are on the T-1. Voice lines usally use D4 and data lines use ESF. D4 lines you cannot run Nx64 DS0's, ESF you can run Nx64 and Nx56. ESF has the advantage of the two types of framing. You can probably run an E-1 channelized and unframed, but why would you? If the line provides for framing for sycronization advantages, then run the line as such. No carrier is really going to provide to you an unframed channeled E-1 unless you ask for it...Good Luck...

jemekeren Tue, 04/17/2007 - 04:28

unframed looks good since its use for full it danger since no synch mechanism exist? so why there exists framed unchanneled? how to configure link in framed unchanneled and framed channeled. i want to create point2 point e1. no voice there. what is the best? unframed, frame(chanelled) or framed (unchanneled). tx for your help! :) cbeers.

Paolo Bevilacqua Tue, 04/17/2007 - 04:50


Unframed E1 is supported only on certain Cisco hardware, what do you have ?

However the difference between framed mode with 31 timeslots and unframed is negligible, 1984 Kbps vs. 2048.

Hope this helps, if so please rate post!


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