ServerNet Cluster Manual

ServerNet Cluster Description
ServerNet Cluster Manual—520575-003
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ServerNet Cables for Each Node
ServerNet II Switch. Figure 1-15 shows the AC transfer switch in a cluster switch
enclosure.
ServerNet Cables for Each Node
ServerNet cables provide ServerNet links between routing devices. The cables are
available in 10-meter, 40-meter, and 80-meter lengths. An 80-meter plenum-rated
cable is also available. Fiber-optic ServerNet cables must meet the specifications
shown in Table 2-5 on page 2-12.
In a ServerNet cluster, single-mode, fiber-optic cables link each node to a cluster
switch. Two ServerNet cables are needed for each node. One cable connects the
MSEB in slot 51 of group 01 to the cluster switch serving the X fabric. The other cable
connects the MSEB in slot 52 of group 01 to the cluster switch serving the Y fabric.
Connections Between Cluster Switches
ServerNet clusters using either the split-star topology or the tri-star topology require
additional fiber-optic ServerNet cables to connect cluster switches on each fabric. The
connections between two cluster switches are called a multilane link. The split-star
topology and the tri-star topology use a different type of multilane link.
Four-Lane Link Used In the Split-Star Topology
In the split-star topology, the two cluster switches on each fabric are connected by a
four-lane link consisting of four fiber-optic cables. Ports 8 through 11 of the two cluster
switches are used for the four-lane link. Traffic travels in both directions across a four-
lane link.
Cluster switches X1 and Y1 send traffic from ServerNet nodes 1 through 8 across the
four-lane link to cluster switches X2 and Y2 for routing to ServerNet nodes
9 though 16. Figure 1-17 shows how traffic is routed across the four-lane links.
Note. Relay scrubbing is not supported for the AC transfer switch. For most installations, the
UPS provides backup power for enough time for you either to replace or bypass the AC
transfer switch in the event of a failure.
Note. All four fiber-optic cables are required for a four-lane link, regardless of the number of
nodes in the split-star topology.