Reminiscing our first internet connections (WAS) Re: akamai yesterday - what in the world was that

Mon Feb 17 23:37:26 UTC 2020

On 17/Feb/20 22:43, Clayton Zekelman wrote:
>
> A PRI was and still is 23B+D, not 24 2B+D lines.

In Africa (and much of Europe and Asia, I believe), our PRI's were E1's,
which was 30B+2D (CCS and CAS protocols), for a total carriage bandwidth
of 2.048Mbps.

For E1, timeslot 0 is used for clocking and synchronization and is not
considered either a B- or D-channel. Timeslot 16 is used for the
D-channel (which I believe is timeslot 24 for a T1).

In E1, the D-channels can be configured differently depending on which
protocol is in use. For example, if you are using SS7 for an E1 PRI, you
can have 31B+1D, which means timeslot 16 is not used for signaling.

Mark.