4-6
Cisco MGX 8800/8900 Series Hardware Installation Guide
Releases 2 - 5.2, Part Number OL-4545-01, Rev. H0, May 2006
Chapter4 Planning for Card Redundancy, Line Redundancy, and Bulk Distribution
Planning Standalone and Redundant Card Configurations
Preconfigured Redundancy (PXM and SRM)
Cisco MGX 8850switches are preconfigured to support redundant PXM and SRM cards. If you want to
use redundant PXM and SRM cards, simply install cards in the appropriate slot as des cribed in Tabl e 4-3.
SRM cards are optional and add 1:N card redundancy, bulk distribution, and bit error rate testing (BERT)
services to a Cisco MGX 8850switch. These services apply to select service modules, so in a MGX 8850
(PXM45) or MGX 8850/B switch, for example, you might use 1:1 card redundancy for some cards and
1:N redundancy for others.
When you install SRM cards, it is important to note the relationship between the SRM cards and the
PXM cards, which is shown in Table 4- 3. For example, in a MGX8850 (PXM1E) switch, the primary
preconfigured card set is a PXM in slot 7, an SRM covering the upper bay in slot 15, and an SRM
covering the lower bay in slot 31. The secondary configuration is a PXM in slot 8, an SRM covering the
upper bay in slot 16, and an SRM covering the lower bay in slot 32. If the primary card set fails, a
switchover to the secondary card set is initiated. Figure4-1 and Figure 4-2 show the card positions for
PXM and SRM cards in the switches that support SRM cards.
Figure4-1 MGX 8850 Switch or MGX 8880 Media Gateway with Redundant PXMs and SRMs
Table4-3 Preconfigured Redundancy for Cisco MGX 8850Switches
Switches
Redundancy
Role PXM Slot
Upper Bay
SRM Slot
Lower Bay
SRM Slot
MGX 8830 and MGX 8830/B Primary 1 7 —
Secondary 2 14 —
MGX 8850 (PXM1E/PXM45), MGX
8850/B and MGX 8880
Primary 7 15 31
Secondary 8 16 32
MGX 8950 Primary 7 — —
Secondary 8 — —
89872
151413121110987654321 16
3130292827 32222120191817 2625
P
X
M
1
E
or
P
X
M
4
5
P
X
M
1
E
or
P
X
M
4
5
S
R
M
S
R
M
S
R
M
S
R
M