ServerNet Cluster Manual

Planning for Installation

ServerNet Cluster Manual—520575-003

2-10

Alternate Cluster Switch Packaging

The cluster switches are typically packaged in a switch enclosure that is half the height

of a NonStop S-series system enclosure. (See Figure 1-14 on page 1-27.) However,

the components of a cluster switch can also be ordered separately and installed in a

19-inch rack that you provide. The rack must be an EIA standard rack that is 19 inches

wide and 24 to 26 inches deep. For more information about the cluster switch, refer to

Section 1, ServerNet Cluster Description.

Two Fiber-Optic Cables Needed for Each Server

Each server that joins a ServerNet cluster requires two single-mode fiber-optic cables.

These cables connect the MSEBs in group 01 of the server to the cluster switches. The

maximum length for these cables is 80 meters. Figure 2-6 on page 2-19 shows the

maximum cable lengths.

Fiber-Optic Cables for Multilane Links

If your cluster uses more than one cluster switch per fabric, you need additional fiber-

optic cables for the multilane links between the cluster switches.

The number of fiber-optic cables you need depends on the number of cluster switches

and the topology you are using. To determine how many fiber-optic cables you need for

multilane links, see Table 2-3 on page 2-9.

Cables up to 80 meters in length are supported for multilane links in the split-star and

tri-star topologies. However, you can use longer cables between cluster switches if the

requirements in Table 2-4 are met.

Caution. Do not exceed the 80-meter maximum cable length between a ServerNet node and

a cluster switch. Doing so can cause multiple, unrecoverable link failures to and from the node

that is in violation of the distance limit.