Starting in the Solaris 8 release, you can use per-route metrics to associate
some properties with IPv4 and IPv6 routing table entries.
For example, a system has two different network interfaces, a fast Ethernet interface
and a gigabit Ethernet interface. The system default tcp_recv_hiwat is 24,576 bytes.
This default is sufficient for the fast Ethernet interface, but may not be
sufficient for the gigabit Ethernet interface.
Instead of increasing the system's default for tcp_recv_hiwat, you can associate a different
default TCP receive window size to the gigabit Ethernet interface routing entry. By
making this association, all TCP connections going through the route will have the
increased receive window size.
For example, the following is in the routing table (netstat -rn), assuming IPv4:
188.8.131.52 184.108.40.206 U 1 4 hme0
220.127.116.11 18.104.22.168 U 1 4 ge0
default 22.214.171.124 UG 1 8
In this example, do the following:
# route change -net 126.96.36.199 -recvpipe x
Then, all connections going to the 188.8.131.52 network, which is on the ge0
link, use the receive buffer size x, instead of the default 24567
receive window size.
If the destination is in the a.b.c.d network, and no specific routing entry
exists for that network, you can add a prefix route to that network
and change the metric. For example:
# route add -net a.b.c.d 184.108.40.206 -netmask w.x.y.z
# route change -net a.b.c.d -recvpipe y
Note that the prefix route's gateway is the default router. Then, all connections
going to that network use the receive buffer size y. If you have
more than one interface, use the -ifp argument to specify which interface to
use. This way, you can control which interface to use for specific destinations.
To verify the metric, use the route(1M) get command.