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Cisco MGX 8800/8900 Series Hardware Installation Guide
Releases 2 - 5.2, Part Number OL-4545-01, Rev. H0, May 2006
Chapter 4 Planning for Card Redundancy, Line Redundancy, and Bulk Distribution
Planning for Standalone and Redundant Line Configurations
• For VXSM-4-155 cards, the working line connects to a port on the upper bay back card and the
protection line connects to the corresponding port on the lower bay back card. For example, if port
2 is configured for intracard APS, the working line is connected to port 2 in the upper bay and the
protection line is connected to port 2 in the lower bay.
• For all cards except VXSM-4-155, the working line must be assigned to an odd-numbered port. For
example, the working line could be line 1 and the protection line could be line 2.
• For all cards except VXSM-4-155, the working line must be assigned to a lower numbered port than
the protection line. For example, the working line could be on port 3 and the protection line on port
4. If the protection line is on port 2, do not assign the working line to port 3.
• The switches at both ends of the APS lines must be configured for APS, and the role of each line
(working or protection) must be the same at both ends of the line.
• Slot 4 in the MGX 8880 uses redundancy back cards that connect the front card in slot 4 to any back
cards in slot 3. Because slot 4 cannot support intracard APS on its own, it is recommended that you
use slot 3 and not slot 4 for standalone card operation with intracard APS, or, that you use 1:1 card
redundancy in slots 3 and 4 with intracard APS as described in the next section.
• Because the AXSM-1-2488, AXSM-1-9953-XG, and SRME cards have only one port on their back
cards, they cannot be configured for intracard APS operation. They can be configured for intercard
APS, which is described later in this chapter. This also applies to SRME/B cards that use SONET
or SDH interfaces.
Intercard APS Configurations
Intercard APS configurations are created with the working and protection lines on different back cards.
As shown in Figure 4-10, intercard APS makes it possible to extend the fault tolerance provided by
redundant front cards to back cards and lines.
Figure 4-10 Redundant PXM1E Configuration with Intercard APS
PXM1E front cards
80149
Midplane
PXM-UI-S3/B back cards
OC-3c or OC-3c/DS3 combination back cards
1
2
1
2
Working line 1.1
Protection line 1.1
Protection line 1.2
Working line 1.2