Configuring and Managing Host-Based X.25 Links - Edition 5 (36939-90054)

110 Chapter5

Preparing to Conﬁgure X.25 iX System Access

Identify Neighbor Gateways

This section only applies if one of the nodes on your network is a

gateway. A neighbor gateway is a gateway that is on the same network

as a given node. A non-gateway node on a network may need to go

through a neighbor gateway in order to send messages to an entirely

different network. Two nodes are on the same network if the network

portion of their IP addresses are the same. All X.25 nodes on the same

network need to know the identities of any accessible neighbor

gateways. Therefore, when using NMMGR to conﬁgure any node, you

will be entering the identities of all the neighbor gateways into the

conﬁguration of the node. Following is an example:

Example: Identifying Neighbor Gateways of Node B

In Figure 5-3, Net 1 is a LAN, Net 2 is an X.25 network, and Net 3 is a

point-to- point network. Node A is on both Net 1 and Net 2 and is a full

gateway between them. Node A is the Neighbor Gateway for all nodes

on Net 1 to reach Net 2. Node C is on Net 1 and Net 3 and is a gateway

half. Node C is the Neighbor Gateway for all nodes on Net 1 to reach

Net 3.

If you were conﬁguring a node such as Node B in Figure 5-3, you would

enter the identities of Nodes A and C as neighbor gateways of Node B

(at the Neighbor Gateways screen and the Neighbor Gateway

Reachable Networks screen). On the Neighbor Gateway Reachable

Networks screen, you would also enter the IP address of Network 2 as a

Conﬁgured Reachable Network reachable through gateway Node A and

the IP address of Network 3 as a Conﬁgured Reachable Network

reachable through gateway Node C.