Nortel Web OS 10.0, Application Manual

Page: 35 / 482

Web OS 10.0 Application Guide
Chapter 1: Basic IP Routing
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212777-A, February 2002
Defining IP Address Ranges for the Local
Route Cache
A local route cache lets you use switch resources more efficiently. The local network address
and local network mask parameters (accessed via the
/cfg/ip/frwd/local/add
com-
mand) define a range of addresses that will be cached on the switch. The local network address
is used to define the base IP address in the range that will be cached. The local network mask is
applied to produce the range. To determine if a route should be added to the memory cache, the
destination address is masked (bit-wise AND) with the local network mask and checked
against the local network address.
By default, the local network address and local network mask are both set to 0.0.0.0. This pro-
duces a range that includes all Internet addresses for route caching: 0.0.0.0 through
255.255.255.255.
To limit the route cache to your local hosts, you could configure the parameters as shown in the
following example:
N
OTE
–
Static routes must be configured within the configured range. All other addresses that
fall outside the defined range are forwarded to the default gateway.
Table 1-4 Local Routing Cache Address Ranges
Local Host Address Range Local Network Address Local Network Mask
0.0.0.0 - 127.255.255.255 0.0.0.0 128.0.0.0
128.0.0.0 - 128.255.255.255 128.0.0.0 128.0.0.0 or 255.0.0.0
205.32.0.0 - 205.32.255.255 205.32.0.0 255.255.0.0