Expand Configuration and Management Manual (H06.03+)

Planning a Network Design
Expand Configuration and Management Manual—529522-002
3-6
ServerNet Connections
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Passthrough capability. Packets sent over an ATM network path can be forwarded
to another Expand line-handler process, which can be a different line type and in a
different processor.
ServerNet Connections
The Expand-over-ServerNet line-handler process provides connectivity to a ServerNet
cluster, which uses this process to provide a very high speed proprietary interconnect
between systems over a limited geographic range.
The Expand-over-ServerNet line-handler process accesses the network access
method (NAM) interface of the ServerNet cluster monitor process, $ZZSCL. The major
benefits of connections using ServerNet clusters are
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Faster transmission speed and larger packet sizes. The ServerNet II cluster switch
uses router-2 technology, which provides crossbar wormhole routing of ServerNet
packets between 12 input ports and 12 output ports. (The ServerNet I cluster
switch is not supported.)
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Fault-tolerance. The ServerNet cluster uses one ServerNet II cluster switch for the
X fabric and one ServerNet II cluster switch for the Y fabric. These two cluster
switches can support up to eight nodes. For fault-tolerance, each node connects to
both cluster switches.
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Connectivity. ServerNet clusters can coexist with ATM or IP networks and other
WAN and LAN products.
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Manageability. The ServerNet cluster’s quick-disconnect capability makes it easier
to implement planned outages.
An Expand-over-ServerNet line-handler process can be configured as a single line
only; Expand-over-ServerNet lines cannot participate as a member of a multi-CPU path
(superpath).
Refer to Time Factors and Pathchange Messages on page 17-23 for information on
adjusting settings so that routing is optimal.
Defining Paths Between Systems
Each system in an Expand network can have up to 255 Expand line-handler
processes. An Expand line-handler process can be configured to handle a single line
or a path consisting of up to eight parallel lines. You can also associate up to 16
Expand line-handler processes in separate processors with one another to form a
multi-CPU path.
This subsection provides information to help you determine when to
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Configure a single-line Expand line-handler process
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Configure a multi-line path between neighbor nodes
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Configure a multi-CPU path
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Enable the multipacket frame feature