IS-IS Network Design Solutions

Link-State Packet TLVs

The previous sections of this chapter reviewed the LSP packet format and discussed fields in the LSP header. As shown in Figure 5-2, TLV fields are appended to the header of an IS-IS packet, depending on its type and the specifics of the routing environment, to form the complete packet. This section covers the TLVs defined for Level 1 and Level 2 LSPs by ISO 10589 and RFC 1195. Table 5-3 lists the TLVs for Level 1 LSPs defined in both standards, and Table 5-4 lists the TLVs for Level 2 LSPs. Some TLVs are used in both Level 1 and Level 2 LSPs. Those unique to a specific level of LSP are bolded. Some of the recent TLVs defined by the IETF for various extensions to Integrated IS-IS, such as MPLS traffic engineering, are covered ...