I feel you are talking about ISDN PRI line which consists of 30 Channels each of 64Kbps which you can make use primarily for backup purpose.
Scenarios like a Central Office having number of remote branches which needs a backup line to the primary link. In this case at the central office instead of taking individual bri links take a PRI line and make use of the channels to provide redundant isdn connectivity to the remote locations.
Also you can make use of entire 30 Channels as a backup solution for a primary link.
Many providers sell the ISDN30 as a voice only 30 channel line with a telephone number attached. An E1 is usually data, and can either be a full E1 using all 30 channels, or a partial E1 which would have lower bandwidth. Be aware as not al E1 cards will do partial E1 config.
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...