[nsp] What WIC to use with E1 service

[Stephen J. Wilcox]

On Sat, 8 May 2004, Gert Doering wrote:

> Hi,
> 
> On Sat, May 08, 2004 at 09:55:58AM -0400, Krzysztof Adamski wrote:
> > > Other carriers (COLT, for example) usually deliver "unframed" only
> > > anyway...
> > 
> > The circuit is being delivered in Belgium by FranceTelecom.
> 
> I have no experience with them.  Sorry.
> 
> > On my end it is delivered by 360, and it looks like the people that I'm
> > dealing with have not done this before, so extracting recommendations from
> > them is difficult. Every answer has "this should work" instead of "this
> > will work".
> 
> Expect "it will not work, and nobody can tell you how it was supposed to
> work in the first place" :-(
> 
> > Here are the options that 360 told are available:
> > 
> > E1: G.703/G.704 framed or G.703 unframed
> > hence framing options: CRC4 or NO-CRC4
> > coding: AMI or HDB3 (HDB3 most common for data)
> > 
> > The E1 will be used just for data and will terminate on a T1 on my end.
> > The other mystery is how will the E1 be changed into T1 on my end?
> 
> Now this is interesting.  I have no idea how this is planned, but they
> might try something like this:
> 
> The E1, when run with G.703/G.704 framing, has 32 timeslots, 64kbit/s
> each.  Of those, *up to* 31 can be used for data - on a VWIC-Interface, 
> this is configured as, for example
> 
> contr e1 0/0
>   channel-group 0 timeslot 1-31
> 
> to use 1984 kbit/s (the maximum for E1 / framed - ts 0 is used for frame
> sync).
> 
> T1 has 23 timeslots.  So it *might* work if you just use
> "channel-group 0 timeslot 1-23"
> on the E1 end, and the telco has some multiplexing device that takes
> 23 individual DS0's from the E1 side, and feeds them into the T1 side.
> 
> All of this is guesswork, of course.  You need hard data how they
> do the E1/T1 conversion to decide how to configure your end.

Probably correct tho.. the E1/T1 framing are incompatible. Afaik most people 
doing this usually order one type of circuit and apply a convertor on one end, 
this may be the safer option if the carrier is unclear on how or if this will 
work.

Steve