Download Configuration Guide

Setting Static Routes
This workaround works only if all the products involved are PortMaster products, with
the following two exceptions:
•
If you use a netmask table entry of 255.255.255.255. In this case, the routes
broadcast as host routes really are host routes, so third-party routers can use them.
Keep in mind that not all routers accept host routes.
•
If the third-party router can convert host routes into subnet routes through some
mechanism of its own.
Uses for Static Netmasks
The most common use for the static netmask table is to split a single class C network
into eight 30-host subnets for use in assigned pools. Subnetting allows each PortMaster
to broadcast a route to the subnet instead of claiming a route to the entire class C
network. An example of that use is provided in “Example of Applying Static Netmasks”
on page 3-24.
The next most common use for the static netmask table is to allow dial-in users to use
specified IP addresses across multiple PortMaster products in situations where assigned
IP addresses are not sufficient. This use can result in very large routing tables and is not
recommended except where no other alternative is possible.
The netmask table can be accessed only through the command line interface. To add a
static netmask, use the add netmask command. To delete a static netmask, use the
delete netmask command. The show table netmask command shows both dynamic
netmasks and static netmasks, marking them accordingly.
✍
Note – Static routes use the netmask table entries that are in effect when the routes are
added. If the netmask table is changed, the static route must be deleted from the route
table and added again.
Example of Applying Static Netmasks
Note – Lucent recommends that you use OSPF in this circumstance instead of static
routes.
This static netmask example assumes the following:
3-24
•
You have anywhere between 8 and 250 PortMaster routers.
•
You assign all the user addresses from the dynamic address assignment pools on the
PortMaster routers.
PortMaster Configuration Guide