1. Fractional E1 - An E1 interface is presented to your equipment. Only some of the channels are active, and they are point-to-point channels.
2. Fractional PRI ISDN - An E1 is presented to your equipment. One of the channels (15, I think - I'm a Yank so I'm not sure) acts as the D channel for signalling between your equipment and the switch. Some, but not all (therefore "fractional") of the channels are used for end-to-end data on a per-call basis. These are called B channels
3. E1 - An E1 is presented to your equipment. All channels are available for your data on a point-to-point basis.
4. PRI ISDN - Same as 2 above, but all channels except the D channel are available as B channels.
An E1 line is simply 2 Mbps of data. E1 Channelized formats that 2 Mbps line in a standard fashion so that there are 30 64kbps channels on it. A multiplexer can use this format to turn up a number of these channels to the user.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...