The show isis database Command
The show isis database command shows the LSPs held in the local database. The LSP ID shows the system ID of the generating router and whether this LSP is from a router or a pseudonode. The last octet shows whether the LSP was too large to fit into one PDU a nonzero value in this field indicates that this is a fragment of an LSP. The number states the fragment number. Because IS-IS is a link-state protocol, the database should be identical on every router of the same level within the area. The...
The show isis database detail Command
The show isis database detail command shows the complete LSP and the values for the individual fields. The EXEC command has the same syntax structure as shown in the show isis database command in the preceding section. Example 12-12 shows output for the show isis database detail command. The highlighted lines show that there are two databases one for the Level 1 routing and the other for the Level 2 routing. The example shows, for each LSP, the area and the IP address of the transmitting...
The show clns interface Command
The misconfiguration of the interface for Integrated IS-IS results in the inability to create adjacencies. Typically, the error is a simple mismatch of parameters, which can be seen by using the show clns interface command. The neighbor database tells you of one neighbor, and the interface indicates one adjacency. Because this is a LAN interface, it is possible to identify the DIS. The circuit ID shows the pseudonode ID, which has a value greater than 0x00 in the octet after the system ID. Note...
Configuring NBMA
IS-IS acknowledges only two types of network topologies broadcast and point-to-point. If the network link is not a serial line connecting to a single router (a point-to-point network), IS-IS automatically defines the link to be broadcast. Because NBMA is neither a point-to-point nor a broadcast medium, the configuration for IS-IS over NBMA deserves a moment's consideration. For multiaccess WAN interfaces (such as ATM, Frame Relay, and X.25), it is highly recommended that you configure the NBMA...
Do I Know This Already Quiz
The purpose of the Do I Know This Already quiz is to help you decide what parts of this chapter to use. If you already intend to read the entire chapter, you do not necessarily need to answer these questions now. The 12-question quiz, derived from the major sections in the Foundation Topics portion of the chapter, helps you determine how to spend your limited study time. Table 12-1 outlines the major topics discussed in this chapter and the Do I Know This Already quiz questions that correspond...
