TCP/IP (Parallel Library) Configuration and Management Manual

Configuring Parallel Library TCP/IP for Complex and
Heavy-Use Environments
HP NonStop TCP/IP (Parallel Library) Configuration and Management Manual—522271-006
3-10
Hybrid Listener Model
Figure 3-5 shows the hybrid listener model in conventional TCP/IP. The figure shows
two distributors in processors 0 and 2 distributing connections and data and control
flow to servers in their own and in one other processor. The servers inherit the
connections and send data flow to the TCP/IP process. Note that each TCP/IP process
represents a different IP host. Also note the remote IPC hop between the servers in the
remote processors (1 and 3) and the processors with the TCP/IP stack (0 and 2). In
addition, note the local IPC hop between the servers and the TCP/IP processes in the
processors containing the TCP/IP stacks.
The hybrid listener model can benefit from Parallel Library TCP/IP because you can
enable round-robin filtering and run multiple instances of the hybrid distributor in
different processors bound to the same port. Round-robin filtering enables the adapter
to distribute incoming connections to the multiple distributor instances, for connection
parallelism. Then the distributors hand off the connections to available servers,
allowing reactive distribution. The servers have direct access to the TCP/IP library in
their own processors, eliminating both the remote IPC hops and local IPC hops. All the
distributors share the same port and present a single IP host to the outside world.
Figure 3-6 shows a configuration (simplified for comparison) with two distributors: one
in processor 0 and one in processor 2. The distributors hand off connections to servers
in their own processor and in one remote processor. All connections go through the
same G4SA LIF and the G4SA round-robin distributes connections among the
distributors. A single IP host is presented to the outside world and the inter process
Figure 3-5. Hybrid Listening Model in Conventional TCP/IP
LAN Adapter
VST0305.vsd
Distributor
Processor 0 Processor 1 Processor 2 Processor 3
Local
IPC
hop
Distributor
TCP/IP
Process
Two IP Hosts
Server
Server
Server
Server
Server
Server
Server
Server
Server
Connection
Distribution
TCP/IP
Process
Server
Server
Server
2
1
Legend
Data flow
Connection hand offs
1
11
2
2
2
2
1
LAN Adapter
IPC Hop