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Service Resource Module
Cisco MGX 8850 Installation and Configuration, Release 1.1.00, Part Number 78-6186-02
6-48
Bulk Distribution for T1 Service
The MGX-SRM-3T3/B supports a de-mulitplexing function called bulk distribution. With bulk
distribution, the MGX-SRM-3T3/B converts traffic from its T3 lines to T1 channels and sends the
data streams across the distribution bus to the appropriate service modules. The benefit of this
feature is that the number of T1 cables and back cards is greatly reduced. Applicable service modules
are the MGX-AUSM/B-8T1, AX-FRSM-8T1, and MGX-CESM-8T1.
At its MGX-BNC-3T3-M back card, the MGX-SRM-3T3/B connects to an external multiplexer. The
multiplexer connects to the T1 lines from user-equipment and places the data streams on T3 lines to
the MGX-SRM-3T3/B. Each T3 line can contain 28 T1 channels. An individual MGX-SRM-3T3/B
can support 10 card slots, so the maximum number of T1 channels it can process is 80.
Linking the MGX-SRM-3T3/B to a destination card causes the switch to take CPE traffic through
the MGX-SRM-3T3/B rather than the T1 card’s line module. Linkage is a card-level condition. If
you link just one T1 channel on a service module to the MGX-SRM-3T3/B, the back card on the
service module becomes inoperative, so you must link all other T1 ports on that service module to
the MGX-SRM-3T3/B if you want them to operate. Linking T1 ports into a group does not form an
N X T1 channel. Each T1 channel remains a distinct T1 channel. Furthermore, a group belongs to
one slot, so it cannot include T1 channels belonging to another card.
For a description of how the MGX-SRM-3T3/B supports redundancy for linked channels, see the
section “Redundancy Support by the MGX-SRM-3T3/B” in this chapter.
Before configuring bulk distribution on an SRM, perform the following tasks:
1 Activate the lines (addln on the CLI).
2 Optionally configure the lines (cnfln on the CLI).
3 Display the state of the lines (dspln and dsplns on the CLI).
To link T1 ports on a service module to a T3 line on an MGX-SRM-3T3/B:
• Execute addlink on the active PXM. Related commands are dsplink and dellink.
addlink <T3 line number> <T1 slot> <NumberOfT1s> <TargetSlotLineNum>
Redundancy Support by the MGX-SRM-3T3/B
The MGX-SRM-3T3/B can provide redundancy to service modules with T1 or E1 lines. For E1 or
T1 modules, it can provide redundancy through the redundancy bus. For T1 modules only, it can
provide redundancy through the distribution bus. The redundancy and distribution buses impose
different requirements, but the common requirement is that all primary and secondary cards
supported by a particular MGX-SRM-3T3/B must reside on the same level of the card cage as that
SRM.
T3 line number is the line number in the format slot.line, where slot is 15 or 31
(regardless of whether redundant SRMs exist in slots 16 and 32),
and the range for line is 1–3.
T1 slot is the start T1 line number within the T3 line (range 1–28).
NumberOfT1s is the slot number of the T1 service module. Target Slot number
can be 1-6, 11-14, 17-22, or 27-30.
TargetSlotLineNum is the T1 line number in the linked card slot. The range is 1–8.