ServerNet Cluster Manual

ServerNet Cluster Description
ServerNet Cluster Manual—520575-003
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ServerNet Cluster Hardware Overview
ServerNet Cluster Hardware Overview
ServerNet clusters use the following hardware components:
•
Routers
•
Service processors (SPs)
•
Modular ServerNet expansion boards (MSEBs)*
•
Plug-in cards (PICs)*
•
Node-numbering agent FPGAs
•
Cluster switches*
•
ServerNet cables*
*For service categories, refer to Appendix D, Service Categories for Hardware
Components.
Routers
In a NonStop S-series server, routers route messages across ServerNet links. The
following customer-replaceable units (CRUs) contain routers:
•
Processor multifunction (PMF) CRUs and PMF2 CRUs
•
I/O multifunction (IOMF) and IOMF 2 CRUs
•
ServerNet expansion boards (SEBs)
•
Modular ServerNet expansion boards (MSEBs)
•
ServerNet II Switches (main component of cluster switch)
The MSEB and ServerNet II Switch use router-2 technology. The router-2 is a
proprietary design, application-specific integrated circuit (ASIC) that provides wormhole
routing of ServerNet packets between 12 input ports and 12 output ports. The ASIC
contains a 12-way crossbar switch that receives data packets, checks them for errors,
interprets their destination addresses, and then routes the packets out one of its 12
output ports.
The router-2 ASIC supports the ServerNet II protocol. Because the external ServerNet
fabrics contain MSEBs and ServerNet II Switches that use the router-2, ServerNet
clusters can take advantage of the faster speeds and larger packet sizes of
ServerNet II.
Service Processors (SPs)
Service processors (SPs) are components of the processor multifunction (PMF),
PMF2, I/O multifunction (IOMF), and IOMF 2 CRUs. SPs assign ServerNet IDs to
processors and I/O devices within a NonStop S-series server. They also configure the
SEBs and MSEBs to route packets between these devices.
For ServerNet clusters, the SPs:
•
Assign ServerNet IDs for the processors in a server in a regular fashion, such that
a client can request a ServerNet ID for a given processor in a given (logical) node
from any master service processor (MSP) in any node in the ServerNet cluster.