---
layout: default
---
:source-highlighter: coderay
:icons: font

include::banner.adoc[]

== Bus (Routing)

image::bus.png[A Simple Bus]

The bus protocol is useful for routing applications, or for building
fully interconnected mesh networks.  In this pattern, messages are
sent to every directly connected peer.

.bus.c
[source,c]
----
include::src/bus.c[]
----
<1> Blithely assumes message is ASCIIZ string. Real code should check it.

.Compilation
[source,bash]
----
gcc bus.c -lnanomsg.a -o bus
----

.Execution
[source,bash]
----
./bus node0 ipc:///tmp/node0.ipc ipc:///tmp/node1.ipc ipc:///tmp/node2.ipc & node0=$!
./bus node1 ipc:///tmp/node1.ipc ipc:///tmp/node2.ipc ipc:///tmp/node3.ipc & node1=$!
./bus node2 ipc:///tmp/node2.ipc ipc:///tmp/node3.ipc & node2=$!
./bus node3 ipc:///tmp/node3.ipc ipc:///tmp/node0.ipc & node3=$!
sleep 5
kill $node0 $node1 $node2 $node3
----

.Output
----
node0: SENDING 'node0' ONTO BUS
node1: SENDING 'node1' ONTO BUS
node2: SENDING 'node2' ONTO BUS
node3: SENDING 'node3' ONTO BUS
node0: RECEIVED 'node1' FROM BUS
node0: RECEIVED 'node2' FROM BUS
node0: RECEIVED 'node3' FROM BUS
node1: RECEIVED 'node0' FROM BUS
node1: RECEIVED 'node2' FROM BUS
node1: RECEIVED 'node3' FROM BUS
node2: RECEIVED 'node0' FROM BUS
node2: RECEIVED 'node1' FROM BUS
node2: RECEIVED 'node3' FROM BUS
node3: RECEIVED 'node0' FROM BUS
node3: RECEIVED 'node1' FROM BUS
node3: RECEIVED 'node2' FROM BUS
----