The system ID of the Intermediate System to Intermediate System (IS-IS) node is c867.5309.af89. A network entity title (NET) is a hexadecimal address that consists of the following three parts:
- The area ID
- The system ID
- The network service access point (NSAP) selector, or NSEL

The NET has a minimum length of 8 bytes and a maximum length of 20 bytes. Each byte consists of two hexadecimal characters. The NSEL is the last byte in the address and is typically set to 00.
The system ID is always 6 bytes long and precedes the NSEL. Level 1 routers must have a system ID that is unique within the area, and Level 2 routers must have a system ID that is unique within the domain. ISIS will not establish an adjacency between two routers with the same system ID.

The area ID is of variable length and precedes the system ID. The first byte, which is part of the area ID, is called the authority and format identifier (AFI) and is typically set to a value of 49 on privately addressed networks. Routers that share the same area address can form an adjacency.

In the NET 49.1741.c867.5309.af89.00, the area ID is 49.1741, the system ID isc867.5309.af89, and the NSEL is 00. You can configure a NET for a router by issuing the net command in ISIS router configuration mode. For example, to configure the NET on the node in this scenario, you would issue the command net 49.1741.c867.5309.af89.00.