Networking Concepts

Network Interface and Link Types

An FDDI interface can have only one link configured under it; however, a single link can reach a large number of nodes. FDDI/iX Network Link can support up to 1000 nodes. Up to four FDDI NIs can be active at a time per system.

A Point-to-Point network interface can have up to 40 links configured under it. Point-to-Point links may be dial links, in which a modem attached to a node is used to transmit and receive data carried across telephone wires, or leased lines, in which data is sent over data-grade lines leased from a private carrier. Up to 11

Point-to-Point NI’s can be active at a time (one NI must be loopback) for a total of 12 NI’s per system..

An X.25 network interface can have from one to 11 links configured, depending on the number of configured X.25 network interfaces on the node. (A single node can have up to 11 NIs and up to 11 X.25 links.) Each link can be connected to as many as 1,024 remote nodes, with communication allowed with as many as 256 nodes at the same time. Up to 11 X.25 NI’s can be active at a time (one NI must be loopback) for a total of 12 NI’s per system..

A gateway half network interface can have only one link configured under it (the gateway half link). Links connecting two gateway halves can be only NS Point-to-Point 3000/iX Network links. Only one gateway half NI can be active at a time per system.

If more than one (non-loopback) network interface is configured on a node, the network portions of the IP addresses configured for the interfaces should differ to correspond to the multiple networks to which the node belongs.

Refer to “Software Configuration Maximums” at the end of this chapter for information on configuration path maximums.

Priority of Network Interfaces

If it is possible to reach a destination through more than one active NI, the network determines which NI to select according to the following priority:

Loopback 100VG-AnyLAN 100Base-T FDDI

LAN Token Ring X.25 Gateway Half

Point-to-Point (router)

If more than one NI of a given type is active, (for example, two X.25 NIs) the network will select the one that it finds first.

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Chapter 2