User`s manual

Chapter 1 Overview
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The GFP multiplexer output is managed by the group mapper, instead of the
member groups (the member groups are not connected to the mapper). The
mapper output is then inserted into the SDH frames in reference to the mapping
defined for the primary group.
The main advantage of GFP multiplexing is the way bandwidth allocation is
handled:
 The minimum bandwidth provided to any multiplexed group is guaranteed; it
is always the fraction of primary group bandwidth specified in Step 2.
 If temporarily one of the member groups does not utilize the guaranteed
bandwidth, for example, because of low traffic load, the unutilized bandwidth
is used to carry the traffic of the other groups. Therefore, no bandwidth is
wasted if another user requires it.
The use of GFP multiplexing does not detract in any way from the security
conferred by the uses of port-based VLANs; moreover, only the end points at
which the GFP multiplexing/de-multiplexing taking place are aware of the
multiplexed group structure.
1.6.5 E1 Interface Subsystem
1.6.5.1 E1 Ports
MUXpro operating in SDH networks can be equipped with eight or sixteen
independent E1 ports, which depends on the product model. MUXpro 820 has 8
independent E1 ports and MUXpro 8216 has 16 independent E1 ports. The ports
process the signals as unframed streams.
The E1 interfaces support 120Ω balanced line interface which are terminated in
SCSI II, female connector, with nominal transmit level of ±3V and also support 75
Ω unbalanced interface, with nominal transit level of ±2.37V
Note:
Only secondary groups that are not mapped can be connected
to a GFP multiplexer. For convenience, when a group is added
as secondary group to a GFP multiplexer, its encapsulation
mode is automatically changed to GFP.