Cisco Systems MGX 8230 manual Redundancy Support by the MGX-SRM-3T3/C

Chapter 6 Card and Service Configuration

Service Resource Module

•TargetSlotNum T1 service module slot number to be linked to the T1 line, in the ranges: 3–6 and 10–13.

•TargetSlotLineNum T1 line number in the slot to be linked, in the range 1–8.

Redundancy Support by the MGX-SRM-3T3/C

The MGX-SRM-3T3/C 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/C must reside on the same level of the card cage as that SRM.

The need for back cards and the choice of bus for redundancy support depends on whether the

MGX-SRM-3T3/C must provide bulk distribution:

•With bulk distribution, the T1 service modules do not use back cards. The MGX-SRM-3T3/C uses the distribution bus to support redundancy.

•Without bulk distribution, the supported service modules must have back cards. The redundant card set requires a special redundancy back card (the R-RJ48-8T1 or R-RJ48-8E). The primary card sets use standard back cards (RJ48-8T1 or RJ48-8E1).

With redundancy provided by the SRM, no Y-cables are necessary because the MGX-SRM-3T3/C itself passes the traffic to the redundant front card if a failure necessitates switchover. Conversely, any card with 1:1 redundancy supported by Y-cabling does not require an SRM. For example, the FRSM-VHS cards have 1:1 redundancy through a Y-cable. The MGX-SRM-3T3/C redundancy feature is particularly important for cards that do not have Y-cable redundancy—the T1 and E1 service modules.

Configuring Redundancy Through the Redundancy Bus

For redundancy that utilizes the redundancy bus, the characteristics are:

•Both the primary and the redundant front cards must have back cards. The secondary back card must be the version specifically designed to be redundant cards. Examples are the R-RJ48-8T1 and R-RJ48-8E1, where the first “R” means redundant.

•An MGX-SRM-3T3/C can redirect traffic for only one failed card at a time regardless of the number of redundant groups you have configured to rely on that MGX-SRM-3T3/C for redundancy.

To configure redundancy through the redundancy bus:

Step 1 Execute addred on the active PXM1:

addred <redPrimarySlotNum> <redSecondarySlotNum> <RedType>

where:

•redPrimarySlotNum Slot number that contains the primary card of the card

pair, in the ranges 4–6 or 11–13.

	Cisco MGX 8230 Edge Concentrator Installation and Configuration
Release 1.1.31, Part Number 78-11215-03 Rev. B0, May 2001		6-51