ServerNet Cluster Manual

ServerNet Cluster Description
ServerNet Cluster Manual—520575-003
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Connections Between Cluster Switches
If one lane of the four-lane link is down, traffic for up to four nodes is affected on one of
the fabrics. For example, if port 8 is down at either end, nodes 1 and 2 cannot
communicate with ServerNet nodes 9 through 16 on the affected fabric, and nodes 9
and 10 cannot communicate with ServerNet nodes 1 through 8 on the affected fabric.
To avoid this problem, split-star topologies using G06.14 software (or G06.13 and the
release 3 SPRs listed in Table 3-5) support automatic fail-over of ServerNet traffic on
the four-lane links. For more information, refer to Section 7, Troubleshooting and
Replacement Procedures.
Two-Lane Links Used In the Tri-Star Topology
In the tri-star topology, the three cluster switches on each fabric are connected by three
two-lane links consisting of six fiber-optic cables. Ports 8 through 11 of the cluster
switches are used for the two-lane links. Traffic travels in both directions across the
two-lane links.
Figure 1-18 shows how traffic is routed across the two-lane links.
The tri-star topology features automatic fail-over of ServerNet traffic on the two-lane
links. As long as at least one functional link is healthy between cluster switches,
processor paths between ServerNet nodes can remain up on both fabrics. For more
information, refer to Section 7, Troubleshooting and Replacement Procedures.
Figure 1-17. Routing Across the Four-Lane Links
Routing From
Any Node
Connected to
Cluster Switch
To Distant
ServerNet
Nodes . . .
X1/Y1
X2/Y2
8
9
10
11
8
9
10
11
9 and 10
11 and 12
13 and 14
15 and 16
1 and 2
3 and 4
5 and 6
7 and 8
Uses
Port . . .
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
8
9
10
11
8
9
10
11
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--
--
--
--
--
--
--
--
--
--
--
--
--
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X1 or Y1 X2 or Y2
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