Configuring IP Routing
Configuring the local IP network setup
MultiVoice Gateway for the MAX— User’s Guide
Preliminary November 23, 1998
8-7
Primary IP address for the Ethernet interface
The IP Address parameter specifies the MultiVoice Gateway unit’s IP address for the local
Ethernet interface. When specifying IP addresses for the MultiVoice Gateway’s Ethernet
interfaces, you must specify the subnet mask. IP address and subnet mask are required settings
for the MultiVoice Gateway to operate as an IP router.
Second IP address for the Ethernet interface
The MultiVoice Gateway can assign two unique IP addresses to the physical Ethernet port and
route between them. This feature, referred to as dual IP, can give the MultiVoice Gateway a
logical interface on each of two networks or subnets on the same backbone.
Usually, devices connected to the same physical wire all belong to the same IP network. With
dual IP, a single wire can support two separate IP networks, with devices on the wire assigned
to one network or the other and communicating by routing through the MultiVoice Gateway.
Dual IP is also used to distribute the load of routing traffic to a large subnet, by assigning IP
addresses on that subnet to two or more routers on the backbone. When the routers have a
direct connection to the subnet as well as to the backbone network, they route packets to the
subnet and include the route in their routing table updates.
Dual IP also enables you to make a smooth transition when changing IP addresses. That is, a
second IP address can act as a place holder while you are making the transition in other
network equipment.
Figure 8-3 shows an example of an IP network to connected a MultiVoice Gateway.
Figure 8-3. Sample IP network
Two IP addresses, 12.1.1.2 and 13.9.7.5, are assigned to the MultiVoice Gateway’s Ethernet
interface. The MultiVoice Gateway routes between both networks. The MultiVoice Gateway
enables the host assigned 12.1.1.1 to communicate with the host assigned 13.9.7.4.
The host assigned 12.1.1.1 and the host assigned 13.9.7.4 share a physical cable segment, but
cannot communicate unless the MultiVoice Gateway routes between the 12.0.0.0 network and
the 13.0.0.0 network.
Address = 12.1.1.1
Address = 13.9.7.4
Primary Address = 12.1.1.2
Secondary Address = 13.9.7.5
