Lucent Technologies DDM-2000 OC-3 User Manual

363-206-285
Applications
Issue 3 June 2001
2-35
Hairpin Cross-Connections on Rings 2
The DDM-2000 OC-3 Multiplexer supports a VT1.5 "hairpin" cross-connection
where VT1.5 signals from one Function Unit can be cross-connected to VT1.5
signals in another Function Unit. Figure 2-22 shows a hairpin cross-connection
between Function Unit C and Function Unit A or Function Unit C and Function
Unit B.
The advantage of hairpin cross-connections is equipment savings. If there is a
need to access a DS1 within an OC-3 signal, rather than install another OC-3
shelf, you can use the unused Function Unit slots in any other OC-3 shelf. This
type of cross-connection does not use any time slots on the OC-3 ring itself.
Figure 2-22 also shows how hairpin cross-connections can be used on a ring.
Hairpin cross-connections can also be used in ring configurations with multiple
optical extensions to provide a hubbing topology with a ring at the hub.
See Section 4, "Product Description," for more information on hairpin cross-
connections.
Figure 2-22. VT1.5 Hairpin Cross-Connections
OC-3
EC-1/DS1
VT Hairpin
Function Unit
A or B
Function
Unit C
DDM-2000
OC-3
DDM-2000
OC-3 Ring
DDM-2000
OC-3
DDM-2000
OC-3 Ring

Lucent Technologies DDM-2000 OC-3 Specifications

General

Brand	Lucent Technologies
Model	DDM-2000 OC-3
Category	Multiplexer
Language	English