Cisco MGX 8850 Product Manual page 13

Chapter 2 Module and Service Descriptions
Linking the MGX-SRM-3T3/C to a destination card causes the switch to take CPE traffic through the
MGX-SRM-3T3/C 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/C, the back card on the service module
becomes inoperative. If you want them to operate, you must link all other T1 ports on that service module
to the MGX-SRM-3T3/C.
Module Requirements with Bulk Distribution and Redundancy
The use of bulk distribution affects the requirements for SRM and service module back cards as follows.
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Installation Requirements for the MGX-SRM-3T3/C
The following card-level characteristics apply to any SRM installation:
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SRM Illustration and LED Indicators
Table 2-1
Table 2-1
Type of LED
ACT
STBY
FAIL
1:N RED
Release 1.1.31, Part Number 78-11223-03 Rev. B0, May 2005
With bulk distribution and 1:N redundancy support by way of the distribution bus, the service
modules do not use back cards.
For 1:N redundancy by way of the redundancy bus, the supported service modules must have back
cards—including one special redundancy back card. E1 redundancy requires the AX-R-RJ48-8E or
AX-R-SMB-8E1 line module, and T1 redundancy requires the R-RJ48-8T1 line module.
For bulk distribution, the T3 lines connect to an external multiplexer. The T1 lines on the other side
of the multiplexer connect to the CPE. The SRM converts the received traffic from its T3 lines to T1
channels and sends the data to linked service modules. For instructions on linking T1 channels and
card slots to the MGX-SRM-3T3/C, see
The MGX-SRM-3T3/C and supported service modules must be in the same (top or bottom) bay.
A nonredundant setup requires an MGX-SRM-3T3/C in slot 15 for the upper bay or slot 31 for
redundancy in the lower bay. The PXM1 in slot 7 controls the SRMs in slots 15 and 31.
An optional, redundant PXM1 in slot 8 controls the redundant SRMs in slots 16 and 32.
If the MGX 8850 has one or two primary SRMs for the primary PXM1 and the switch also has a
redundant PXM1, it must have a redundant SRMs. Therefore, the switch can use one, two, or four
MGX-SRM-3T3/Cs.
The distribution bus does not support slots 9, 10, 25, and 26. Any service module that uses bulk
distribution or relies on the distribution bus for redundancy cannot reside in these slots.
contains SRM-3T3 LED faceplate indicators descriptions.
LED Indicators for the SRM-3T3/C
Color
Green
Yellow
Red
Green
Chapter 6, "Card and Service Configuration"
Meaning
Indicates card set is in active mode.
Indicates card set is in standby mode.
Indicates BNM-155 card set has failed or the line
module is missing.
On indicates 1:N redundancy has been invoked.
Off indicates 1:N redundancy is not active.
Cisco MGX 8850 Multiservice Switch Installation and Configuration
Service Resource Module
2-13