NonStop S-Series Server Description Manual (G06.24+)

Introduction

HP NonStop S-Series Server Description Manual—520331-003

1-16

Expansion to Second Processor Enclosure

A pair of ServerNet expansion boards (SEBs) can be used to connect one processor

enclosure to another. Figure 1-9 shows the arrangement of connections.

The main logic component of an SEB is a router that is additional to the one already

present on the MFIOB. SEBs are always added in pairs because one is needed for the

X fabric and one is needed for the Y fabric.

In each case, the router connection from the MFIOB that connects to an SEB is the

router port that was shown unused in Figure 1-7 and Figure 1-8. The four downward-

pointing arrows from the MFIOB routers connect to the SCSI bus and I/O slots like the

example shown in Figure 1-8 on page 1-15.

The required cables for interconnecting the two processor enclosures are shown with

bold lines in the example in Figure 1-9. One cable interconnects the X routers on one

SEB in each of the processor enclosures, and the other cable interconnects the Y

routers.

Note that four unused router ports are available on each of the SEBs. These ports can

be used for expanding either, or both, the number of processor enclosures and the

number of I/O enclosures. Expansions of both kinds are the subject of the remaining

topics in this section.

Note. For clarity, the I/O details are omitted in Figure 1-9. As explained in the preceding topic

(Maximum Processor Enclosure I/O), I/O configuration details vary. For example, because

router 1s have only six ports, slots 51 and 52 are single-ported while slots 53 and 54 are dual-

ported. Router 2s, on the other hard, have 12 ports, and so slots 51 and 52 are also dual-

ported. NonStop S7000, S7400, S70000, and S72000 servers use three, rather than four,

router ports for internal I/O logic.) Two of these ports are for the two ServerNet adapters, and

the remaining two (or one) are for the SCSI buses, Ethernet port, service processor, and

differential SCSI port