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6.2. DODAG Information Solicitation (DIS)

The DODAG Information Solicitation (DIS) message may be used to solicit a DODAG Information Object from a RPL node. Its use is analogous to that of a Router Solicitation as specified in IPv6 Neighbor Discovery; a node may use DIS to probe its neighborhood for nearby DODAGs. Section 8.3 describes how nodes respond to a DIS.

6.2.1. Format of the DIS Base Object

 0                   1                   2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved | Option(s)...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 13: The DIS Base Object
  • Flags: 8-bit unused field reserved for flags. The field MUST be initialized to zero by the sender and MUST be ignored by the receiver.
  • Reserved: 8-bit unused field. The field MUST be initialized to zero by the sender and MUST be ignored by the receiver.
  • Unassigned bits of the DIS Base are reserved. They MUST be set to zero on transmission and MUST be ignored on reception.

6.2.2. Secure DIS

A Secure DIS message follows the format in Figure 7, where the base format is the DIS message shown in Figure 13.

6.2.3. DIS Options

The DIS message MAY carry valid options.

This specification allows for the DIS message to carry the following options:

  • 0x00 Pad1
  • 0x01 PadN
  • 0x07 Solicited Information