TABLE OF CONTENTS Each ND protocol message includes zero or more options. Some options may appear multiple times in a single message. Of the options defined in [RFC2461] the Prefix Information option may appear multiple times in a single Router Advertisement message.
The message options have the general Type-Length-Value (TLV) format as illustrated in Figure 5-15. The Type field specifies the type of option. The Length field specifies the size of the option in 8-byte units, including the size of the Type and the Length fields.
Table 5-2 summarizes the possible option or options that have been defined for each message type.
| Message type | Possible option(s) |
|---|---|
| Router Solicitation | Source Link-Layer Address |
| Router Advertisement | Source Link-Layer Address |
| MTU | |
| Prefix Information | |
| Route Information | |
| Neighbor Solicitation | Source Link-Layer Address |
| Neighbor Advertisement | Target Link-Layer Address |
| Redirect | Target Link-Layer Address |
| Redirected Header | |
| Possible options per message type. |
The Link-Layer Address option can be either the Source Link-Layer Address option or the Target Link-Layer Address option. As shown in Table 5-2 the Source Link-Layer Address option containing the link-layer address of the sender is included in the Router Solicitation messages, the Router Advertisement messages, and the Neighbor Solicitation messages. The Target Link-Layer Address option containing the link-layer address of the target address is included in the Neighbor Advertisement messages and the Redirect messages. The option format is...
