New Options - Message Formats - This document updates the packet formats for the Handover Initi

6. Message Formats

6.4. New Options

All the options, with the exception of Binding Data Authorization for FMIPv6 (BADF) discussed in Section 6.4.5, use the Type, Length, and Option-Code format shown in Figure 10.

The Type values are defined from the Neighbor Discovery options space and Mobility Header options space. The Length field is in units of 8 octets for Neighbor Discovery options, and is in units of octets for Mobility Header options. And, Option-Code provides additional

information for each of the options (see individual options below).

0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

˜ ... ˜ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 10: Option Format 6.4.1. IP Address/Prefix Option

This option is sent in the Proxy Router Advertisement message.

0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| | + + | | + IPv6 Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 11: IPv6 Address/Prefix Option

Type: 17

Length: The size of this option in 8 octets including the Type, Option-Code, and Length fields.

Option-Code:

1: Old Care-of Address 2: New Care-of Address 3: NAR’s IP address

4: NAR’s Prefix, sent in PrRtAdv. The Prefix Length field contains the number of valid leading bits in the prefix. The bits in the prefix after the prefix length are reserved and MUST be initialized to zero by the sender and ignored by the receiver.

Prefix Length: 8-bit unsigned integer that indicates the length of the IPv6 Address Prefix. The value ranges from 0 to 128.

Reserved: MUST be set to zero by the sender and MUST be ignored by the receiver.

IPv6 address: The IP address defined by the Option-Code field.

6.4.2. Mobility Header IP Address/Prefix Option

This option is sent in the Handover Initiate and Handover Acknowledge messages. This option has an alignment requirement of 8n+4.

0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| | + + | | + IPv6 Address/Prefix + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 12: Mobility Header IPv6 Address/Prefix Option

Type: 17

Length: The size of this option in octets excluding the Type and Length fields.

Option-Code:

1: Old Care-of Address 2: New Care-of Address 3: NAR’s IP address

Prefix Length: 8-bit unsigned integer that indicates the length of the IPv6 Address Prefix. The value ranges from 0 to 128.

IPv6 address/prefix: The IP address/prefix defined by the Code field.

6.4.3. Link-Layer Address (LLA) Option

0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Type | Length | Option-Code | LLA...

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 13: Link-Layer Address Option Type: 19

Length: The size of this option in 8 octets including the Type, Option-Code, and Length fields.

Option-Code:

0: Wildcard requesting resolution for all nearby access points 1: Link-Layer Address of the New Access Point

2: Link-Layer Address of the MN

3: Link-Layer Address of the NAR (i.e., Proxied Originator) 4: Link-Layer Address of the source of RtSolPr or PrRtAdv message

5: The access point identified by the LLA belongs to the current interface of the router

6: No prefix information available for the access point identified by the LLA

7: No fast handover support available for the access point identified by the LLA

LLA: The variable-length link-layer address.

The LLA option does not have a length field for the LLA itself. The implementations must consult the specific link layer over which the protocol is run in order to determine the content and length of the LLA.

Depending on the size of individual LLA option, appropriate padding MUST be used to ensure that the entire option size is a multiple of 8 octets.

The New Access Point Link-Layer Address contains the link-layer address of the access point for which handover is about to be attempted. This is used in the Router Solicitation for Proxy Advertisement message.

The MN Link-Layer Address option contains the link-layer address of an MN. It is used in the Handover Initiate message.

The NAR (i.e., Proxied Originator) Link-Layer Address option contains the link-layer address of the access router to which the Proxy Router Solicitation message refers.

6.4.4. Mobility Header Link-Layer Address (MH-LLA) Option

This option is identical to the LLA option, but is carried in the Mobility Header messages, e.g., FBU. In the future, other Mobility Header messages may also make use of this option. The format of the option is shown in Figure 14. There are no alignment requirements for this option.

0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Option-Code | LLA ....

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 14: Mobility Header Link-Layer Address Option Type: 7

Length: The size of this option in octets not including the Type and Length fields.

Option-Code: 2 Link-Layer Address of the MN.

LLA: The variable-length link-layer address.

6.4.5. Binding Authorization Data for FMIPv6 (BADF)

This option MUST be present in FBU and FBack messages. The security association between the MN and the PAR is established by companion protocols [RFC5269]. This option specifies how to compute and verify a Message Authentication Code (MAC) using the established security association.

The format of this option is shown in Figure 15.

0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Type | Option Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| SPI | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| | + + | Authenticator | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 15: Binding Authorization Data for FMIPv6 (BADF) Option Type: 21

SPI: Security Parameter Index. SPI = 0 is reserved for the Authenticator computed using SEND-based handover keys.

Authenticator: Same as in RFC 3775, with "correspondent" replaced by the PAR’s IP address, and Kbm (binding management key) replaced by the shared key between the MN and the PAR.

The default MAC calculation is done using HMAC_SHA1 with the first 96 bits used for the MAC. Since there is an Option Length field,

implementations can use other algorithms such as HMAC_SHA256.

This option MUST be the last Mobility Option present.

6.4.6. Neighbor Advertisement Acknowledgment (NAACK)

0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 16: Neighbor Advertisement Acknowledgment Option Type: 20

Length: 8-bit unsigned integer. Length of the option, in 8 octets. The length is 1 when a new CoA is not supplied. The length is 3 when a new CoA is present (immediately following the Reserved field)

Option-Code: 0

Status: 8-bit unsigned integer indicating the disposition of the Unsolicited Neighbor Advertisement message. The following Status values are currently defined:

1: NCoA is invalid, perform address configuration

2: NCoA is invalid, use the supplied NCoA. The supplied NCoA (in the form of an IP Address Option) MUST be present following the Reserved field.

3: NCoA is invalid, use NAR’s IP address as NCoA in FBU 4: PCoA supplied, do not send FBU

128: Link-Layer Address unrecognized

Reserved: MUST be set to zero by the sender and MUST be ignored by the receiver.

The NAR responds to an UNA with the NAACK option to notify the MN to use a different NCoA than the one that the MN has used. If the NAR proposes a different NCoA, the Router Advertisement MUST use the source IP address in the UNA message as the destination address, and use the L2 address present in UNA. The MN MUST use the NCoA if it is supplied with the NAACK option. If the NAACK indicates that the Link-Layer Address is unrecognized (for instance, if the MN uses an LLA valid on PAR’s link but the same LLA is not valid on NAR’s link due to a different access technology), the MN MUST NOT use the NCoA or the PCoA and SHOULD start immediately the process of acquiring a different NCoA at the NAR.

In the future, new option types may be defined.

Dans le document This document updates the packet formats for the Handover Initiate (HI) and Handover Acknowledge (HAck) messages to the Mobility Header Type (Page 34-40)