Hello,
First of all, E1 stands for 2Mbps transmission.
If your transmited information is carried in a frame ( check ITU G.704
for details ) you can seperate 64Kbps "channels" out of this
2Mbps signal. For example in a TDM infrastructure, you can direct each of these
64K (or better to say n x 64K, 1<= n <= 31 ) channels to different TDM eggress
points.
This is called Channelized E1 (CE1).
With this framing, There are 32 x 64K channels, and channel 0 is used for
framing/synchronization
Channel 16 may be used for signalling if needed, depending on the use of E1
circuit.
(For instance, if PBXs are connected via E1, Channel 16 is used for signalling,
however,
if WAN devices are connected via channels, Channel 16 may be used for an
additional
data channel instead of signalling. For this reason, you may carry a maximum of
30 voice channels over an E1, but 31 x 64 K data channels may be carried)
If infrastructure is not TDM, then you may not need to use 64K seperate
channels.
PDH/SDH infrastructure can be used in this case, and you can use pure
2 Mbps channel. There is no synch or signalling channel loss. (There is no
channel.)
( You may check ITU G.703 )
If your hardware is capable of carrying n x 64 K but not capable of channelizing
them
and not using multiple sub-interfaces over the same interface, then this
fraction of
n x 64K out of E1 is called Fractional-E1
Considering 7200 series routers, Cisco PA-4E1G/120 port adapter is a full rate
E1 card.
If you configure the controller as follows:
controller E1 3/7
channel-group 0 unframed
then you can use Full rate 2Mbps. However if you configure :
controller E1 3/7
channel-group 1 timeslots 1-5
then you have a Fractional E1 interface with a bandwidth of 320Kbps (5x64)
(Unfortunately, this PA does not support multiple channel groups and it is not
channelized.
PA-MC-2E1/120, on the other hand, supports Channelized-E1 ( and also full-rate
E1 with the above commands)
controller E1 3/1
channel-group 1 timeslots 1-15
channel-group 17 timeslots 17
channel-group 18 timeslots 18
and we have 3 subinterfaces of 960Kbps, 64Kbps, 64Kbps respectively.
Hope this helps and not long enough to make it more confusing :-)
Regards,
Ufuk.
"vtam" <[EMAIL PROTECTED]> on 31.08.2000 09:35:34
Department:
Please respond to "vtam" <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
cc: (bcc: UFUK YASIBEYLI/FINANSBANK)
Subject: Help about E1
There are several E1 standard like Channelized E1, Fractional E1, Full rate
E1. What is the different between them? And can i use channelized E1 card
to connect Fractional E1, Full rate E1? Thanks.
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