Expand Configuration and Management Manual (G06.24+)

Subsystem Description
Expand Configuration and Management Manual—523347-008
18-37
Multi-CPU Routing Examples
entry in all processors in the system. If a message is received from a neighbor node
and no RPT entry exists, the message is dropped.
For example, in Figure 18-11, when $NCP on node \A first detects the existence of
node \C, $NCP sends a Connect Request message to node \B which is forwarded
through multi-CPU path 1 to node \C. Later, when the Connect Ack message is sent
from node \A to node \C, $NCP on node \B sets a pointer in the RPT of all its
processors to the Expand line-handler process which received the Connect Ack
message. If PRCA on node \A sends a message to PRCC on node \C, the NRT returns
the Expand line-handler saved in the RPT when the message is received on node \B.
Combination 4: Passthrough Traffic to a Non-Neighbor
Destination Node
In this scenario, a message is received that is destined for a non-neighbor node. The
processor that receives the message simply selects a local path. Passthrough nodes
do not preserve message order, so no Expand line-handler pairing needs to be
established.
For example, in Figure 18-11, if the process named PRCA on node \A sends a
message to the process named PRCF on node \F and $NCP determines that the best-
path route is through node \B and multi-CPU path 1, the NRT on processor 3 on node
\B selects an Expand line-handler process from one of those in processors 1, 2, or 4
based on communications load when the message is received on node \B. The
Expand line-handler process for subsequent messages also is selected based on the
communications load.