Neighbor Gateway Reachable Networks

NOTE: The information configured in this screen can extend to more than one page, if necessary, to allow configuration of up to 2550 reachable networks per link (255 pages and 10 reachable nets per page). Press [Next Page] to proceed to a new page. Press [Prev Page] to display a prior page. Use [First Page] to display the first page (for example, if you are viewing the third page, pressing [First Page] will immediately display the first page). Press [Last Page] to display the last page of configured reachable networks. To consolidate reachable networks entries (from several pages, for example) press [Condense Page].

Fields

Neighbor gateway IP internet address

Enter the full network address of a gateway node (on this network) that is to be used to reach other networks (any network in the same internetwork other than the network of which this node is a member). The network portion of the address must be the same as that entered on the IP Protocol Configuration screen for the network interface you are configuring; however, the node portion need not match.

There are two methods of entering an internet protocol (IP) address within NMMGR:

1. Enter the fully qualified IP address (for example, Class C, C 192.191.191 009)

   OR

2. Enter only the network (nnn) and node (xxx) portions of the IP address as four positive integers between 0 and 255 separated by periods or blanks (for example, 15.123.44.98).

   You need not enter the following items as NMMGR will fill these in:

   - Class A, B, C

   - Leading zeros for the network and node portion of the IP address.

Addresses are made up of a network portion and a node portion. The possible classes of network addresses have the following forms:

Class C:

C nnn.nnn.nnn xxx

Class B:

B nnn.nnn xxx.xxx

Class A:

A nnn xxx.xxx.xxx

where nnn is a value ranging from 000 to 255, representing eight bits of the network portion of an address and xxx is a value ranging from 000 to 255, representing the node portion of the address. Note that network and node values of all zeros or all ones are not allowed. These are special values.

The leftmost group of nnn has the following ranges for each address class:

Class C:

192-223

Class B:

128-191

Class A:

001-126

The network address (network portion of the IP address) configured in NETXPORT.NI.NIname.PROTOCOL.IP must match the neighbor gateway IP internet address configured in the current screen.

Default value: None

Configured reachable networks IP network address

Enter the internet addresses of the remote networks that can be reached through the gateway whose network address is configured in the previous field.

You can also designate this gateway as a default gateway by entering an "at" sign (@) in one of the Configured reachable networks IP network address fields. The network will route messages to the default gateway if it is unable to locate their destination by any other means. The default gateway will then attempt to locate the destination.

When specifying reachable networks, entering only the network portions, and optionally the subnet, of the IP address (setting the node portion to all zeros) allows this node to communicate with any other node on the remote network.

If the remote network is subnetted, you can restrict communication of this node to particular subnets by entering the decimal equivalent of those subnets and including the IP mask in the IP mask field.

To allow this node to communicate with other subnets on the local network, enter the decimal equivalent of the subnet in the IP network address field and enter the subnet mask in the IP mask field. If you do not enter a subnet mask one of the following occurs:

• If the IP address is the same as the node you are configuring, the IP mask entered in the IP Protocol Configuration screen (Figure 5-5 "IP Protocol Configuration Screen") is used.

• If the IP address is different from the node you are configuring, NMMGR assumes no subnetting.

Related screen:

• NETXPORT.NI.NIname.INTERNET

  This path name corresponds to the Neighbor Gateways screen. A Neighbor Gateway Reachable Networks screen must be configured for each gateway configured in the Neighbor Gateways screen.

IP mask

The IP mask identifies a portion of the IP address for subnets. The subnet is specified in the same format as an IP address; that is, the 32-bit mask is grouped in octets expressed as decimal integers and delimited by a "." or a space. For example, a mask for a class A address with the subnet field being the first 8 bits of the node portion would be expressed as 255 255.000.000. The default is no IP mask.

Configured reachable networks hops

Enter the internet hop count to the reachable network whose IP address is configured to the left of the hops field. (The internet hop count is the number of full internet gateways that will be used to route a message to the destination network. If two partner gateway halves are used as part of the internet route, they are counted as one hop.)

Hop count is used internally to determine which neighbor gateway (if more than one exists) is on the shortest path to the remote network. If more than one gateway can reach a given remote network, and the number of hops to the remote network is equal for each gateway, you can specify which gateway the network transport will use by configuring an artificially high hop count. The network transport will always use the gateway with the lowest hop count. If the same hop count value is configured for multiple gateways, the network transport will choose internally from among the routes with equal hop counts.

Range: 1-32767

NOTE: To delete a reachable network entry, fill the field to be deleted with blanks and press the [Save Data] function key.