Riverstone Networks RS Switch Router User Guide Release 8.0 11-3
IP Routing Configuration Guide Configuring IP Interfaces and Parameters
11.2.2 Configuring IP Interfaces for a VLAN
You can configure one IP interface per VLAN. Once an IP interface has been assigned to a VLAN, you can add a
secondary IP address to the VLAN. To create a VLAN called IP3, add ports et.3.1 through et.3.4 to the VLAN, then
create an IP interface on the VLAN:
To configure a secondary address of 10.23.4.36 with a 24-bit netmask (255.255.255.0) on the IP interface int4:
11.2.3 Specifying Ethernet Encapsulation Method
The Riverstone RS Switch Router supports two encapsulation types for IP. Use the interface create ip
command to configure one of the following encapsulation types on a per-interface basis:
•Ethernet II: The standard ARPA Ethernet Version 2.0 encapsulation, which uses a 16-bit protocol
type code (the default encapsulation method).
•802.3 SNAP: SNAP IEEE 802.3 encapsulation, in which the type code becomes the frame length for
the IEEE 802.2 LLC encapsulation (destination and source Service Access Points, and a control
byte).
11.2.4 Unnumbered Interfaces
The Riverstone RS Switch Router allows you to create unnumbered IP interfaces. In the case where an interface is one
end of a point-to-point connection, it is not necessary to associate a particular IP address to that interface. This is
because in a point-to-point connection, packet traffic is going to the other end (or peer) only, and is not routed to any
other destination. Therefore, assigning a unique IP address to that interface wastes addresses within the address pool
allocated by the netmask.
Unnumbered interfaces allow you to use another interface’s IP address. In essence, you configure the unnumbered
interface to borrow the IP address from another interface. This way, the unnumbered interface does not use a unique
IP address for itself, thus conserving addresses within the address pool.
To configure the unnumbered interface ‘int3’ and borrow the IP address from IP interface ‘int1’:
If the interface ‘int1’ has multiple IP addresses, you can specify which address to borrow as shown in the following
example:
rs(config)# vlan create IP3 ip
rs(config)# vlan add ports et.3.1-4 to IP3
rs(config)# interface create ip int3 address-netmask 10.20.3.42/24 vlan IP3
rs(config)# interface add ip int3 address-netmask 10.23.4.36/24 vlan IP3
rs(config)# interface create ip int3 unnumbered int1 port so.3.1
rs(config)# interface create ip int3 unnumbered int1 unnumbered-addr
10.1.1.1 port so.3.1