IS-IS Addressing

CLNP uses a format of addressing, referred to as the network service access point (NSAP) address, to identify individual nodes on a network. Figure 11-4 illustrates the NSAP packet. The NSAP address has a maximum size of 160 bits (20 bytes) and is composed of the following major parts:

  • The initial domain part (IDP)— Made of a 1-byte authority and format identifier (AFI) and a variable-length initial domain identifier (IDI)

  • The domain specific part (DSP)— Composed of fields such as the area ID, system ID, and the N-selector

Figure 11-4. The NSAP Packet

The Simplified NSAP Format

The NSAP format was designed with a hierarchical ...

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