10.7.1 Mobility messages

A message contained in the Mobility Header following IPv6 Header is called the mobility message, which is newly defined in MIPv6. New MIPv6 messages are as follows:

• Home Test Init (HoTI) message

• Home Test (HoT) message

• Care-of Test Init (CoTI) message

• Care-of Test (CoT) message

• Binding Update (BU) message

• Binding Acknowledgement (BA) message

• Binding Refresh Request (BRR) message

• Binding Error message (BE) message

The Mobility Header is identified by the next header value, 135 in the preceding header. The header format is shown in Fig. 10-13. Each field is described as follows.

• The 8-bit Payload Protocol field notifies the header format following the Mobility Header. The value for next header is same as IPv6 Next Header field.

• The 8-bit Header Extension Length field specifies the length of the Mobility Header in 8-byte units except the Next Header field.

• The 8-bit MH type is the identifier among variable Mobility Header types. Current MH type values are specified in Table 10-2.

  Table 10-2: MH type values.

  MH type	Description
  0	Indicates Binding Refresh Request message.
  1	Indicates Home Test Init message.
  2	Indicates Care-of Test Init message.
  3	Indicates Home Test message.
  4	Indicates Care-of Test message.
  5	Indicates Binding Update message.
  6	Indicates Binding Acknowledgement message.
  7	Indicates Binding Error message.

• The next 8-bit field is reserved for the future use and should be initialized to zero by the sender. If this field contains any other value, it should be ignored by the receiver.

• The...