IP Interface Configuration
9-4 Configuring IP Interfaces
IP Interface Type
In this Þeld, use the menu button to select the type of interface you wish to
conÞgure. This selection will change the parameters that appear in the IP
Interface ConÞguration window. Depending on your selection, certain
parameters will be conÞgurable, and others will be grayed out.
There are Þve IP interface types that you can select from:
¥ Rfc 877x25 (X.25)
¥ Ethernet Csmacd (Ethernet II)
¥ Iso 88023 Csmacd
¥ Iso 88025 Token Ring
¥ Frame Relay
Maximum Transmission Unit
This is the maximum size (in bytes) of the data Þeld that can be used to
encapsulate an IP datagram for transmission over the interface. Any datagrams
larger than the Maximum Transmission Unit will be fragmented, resulting in
additional processing on any intermediate routers or gateways, as well as the
destination host. If the maximum Transmission Unit value is less than the size of a
minimal IP datagram, the value will automatically change to the minimal
datagram size. The default value for this parameter is 1500.
Network Mask
This Þeld is used during routing to determine the portion of the IP address
associated with the network and subnetwork (if any). The valid entries are
255.0.0.0 to 255.255.255.255 (255.255.255.255 is only valid on a point-to-point
interface).
The default value for this parameter is conÞgured automatically to reßect the
appropriate address class for the speciÞed Source Address (see below). If the
Source IP Address is changed, the Network Mask will automatically change to a
default value appropriate for the new address. For this reason, conÞgure the
Source IP Address Þrst, then the Network Mask.
If the interface is conÞgured as an Unnumbered Interface (see below), the default
value of Network Mask will be based on the numbered interface that is assigned.
Route Metric Hops
This is the number of network hops (network gateways in the overall path over
the internet) associated with this interface (usually zero). During routing, the
interface with the lowest count will be selected. The default value for this
parameter is 0.
NOTE
The Ethernet and Token Ring IP Interface types will be referred to collectively as LAN
interfaces.