DEFINITY ECS Release 8.2 Maintenance for R8.2csi
555-233-119 Issue 1
April 2000
Maintenance Objects
3-720ISDN-SGR (ISDN-PRI Signaling Group)
3
In an NFAS Signaling Group, the 24th port of a DS1 Interface circ uit pack (for 24
channel interfaces) or the 16th p ort of a DS1 Interface circuit p ack (for 32
channel interfaces) is ad ministered as a D-channel. The D-channel carries
signaling information for the other ports (B-channels) on that c ircuit pack. That
D-channel can also carr y signaling information for any of the ports on other DS1
Interface circuit p acks in the NFAS Signaling Group. As a result, the 24th port on
other 24-channel DS1 Interface circ uit packs and the 16th port on other
32-channel DS1 Interface circ uit packs can b e used as B-channels. A D-cha nnel
in an NFAS Group can signal for B-channels on a total of 20 DS1 Interface c ircuit
packs. This configuration is known as NFAS Simplex.
In addition to NFAS Simplex, there is another type of NFAS Group called NFAS
Duplex. This provides the user with more reliab ility, which is desirable bec ause
NFAS permits the D-channel to signal for so many B-chan nels. NFAS Duplex
allows the administration of a bac kup D-channel, whic h remains in a Standby
state until the Active D-channel g oes down. If the Active D-c hannel does go
down, the backup D-channel takes over and p rovides signaling for all the
B-channels in the signaling group.
The ISDN-PRI Signaling Group itself depends on three other entities: the DS1
Interface circuit p ack on which the D-cha nnel(s) resides, the ISDN-PRI Signaling
Link Port(s), and the Processor Interface Link that p rovides connectivity t o the
processor. If there are any probl ems with the ISDN-PRI Signaling Group, also
investigate the ISDN-PRI Signaling Link Port(s), the DS1 Interface circuit pac k(s).