Zhone Technologies IMACS Network Device - Manual (Page 76)

Zhone Technologies, Inc. IMACS Product Book, Version 4
March 2001 Page 72
Applications
The ISDN PRI Server card can be used in a variety of applications:
•
Fractional ISDN PRI provisioning
•
Video conferencing
•
Integrated ISDN access with SINA
•
Video Broadcast
•
Router with redundant trunk routing via ISDN
•
Router adding incremental bandwidth
•
PRI to FXS
Fractional PRI Provisioning
An IMACS equipped with a 8840C PRI Server card is used to groom multiple fractional PRI circuits into one or
more PRI circuits for backhaul to an ISDN switch. Perhaps a customer may not need the entire bandwidth delivered
by a PRI circuit. The optimal alternative would be to purchase a fractional PRI service delivered over a regular T1
or E1 circuit. When a service provider has multiple fractional PRI customers, the service provider can deploy the
IMACS to groom the multiple fractional PRI circuits into one fully utilized PRI T1/E1 circuit, which is back hauled
to the switch. This concentration of PRI circuits reduced back haul costs for the service provider, and conserves
T1/E1 ports and D-channels on the ISDN switch itself.
Figure 23 shows that three customers are subscribing to ISDN services. Each customer is using a fractional PRI
service. Each customer could be directly connected to the ISDN switch, which would consume three fractional
T1/E1 circuits, and three D channels. Instead, the 3 fractional ISDN circuits are connected to a PRI Server equipped
IMACS. The PRI server grooms the B channels in the three fractional ISDN circuits into one circuit. It also grooms
the three D-channel circuits into a single D channel that is routed to the switch. The IMACS benefits in this
application include saving on back haul costs, switch port costs and switch system resources.
23B+D on T1
30B+D on E1
Customer 1
10B+D
ISDN
Switch
IMACS
Customer 2
7B+D
Customer 3
5B+D
Figure 23—Fractional PRI Provisioning Using IMACS
ISDN Video Conferencing and Video Broadcast
The IMACS is used to connect video-conferencing equipment to an ISDN PRI line. In Figure 24, a video CODEC
is sharing a PRI line with an ISDN PBX. The IMACS is simultaneously routing calls on a call by call basis to either
the PBX, the CODEC, or out to the network. The video-conferencing equipment can be connected via an RS-449
connection with an RS-366 dialer or directly to the IMACS via an ISDN PRI interface. A connection to the
IMACS via the RS-449/RS-366 combination would require the use of a switched HSU card in the IMACS.