Network Working Group A. Muhanna
Internet-Draft M. Khalil
Intended status: Standards Track Nortel
Expires: August 2, 2009 S. Gundavelli
Cisco Systems
K. Chowdhury
Starent Networks
P. Yegani
Juniper Networks
January 29, 2009
Binding Revocation for IPv6 Mobility
draft-ietf-mext-binding-revocation-03.txt
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to this document.
Abstract
This document defines the revocation semantics for terminating a
mobile node's mobility session and associated resources. These
semantics are generic enough and can be used by mobility entities in
the case of Client Mobile IPv6 and its extensions. This mechanism
allows the mobility entity which initiates the revocation procedure
to request its corresponding one to terminate either one, multiple or
all specified binding cache entries.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Conventions & Terminology . . . . . . . . . . . . . . . . . . 4
2.1. Conventions used in this document . . . . . . . . . . . . 4
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
3. Binding Revocation Protocol and Use Cases Overview . . . . . . 4
3.1. Binding Revocation Protocol . . . . . . . . . . . . . . . 5
3.2. Client MIPv6 and DSMIP6 Use Case . . . . . . . . . . . . . 6
3.3. Multi-Care of Addresses (Monami6) Use Case . . . . . . . . 7
3.3.1. Termination of Multiple Care-of Addresses Bindings . . 7
3.3.2. Termination of All Care-of Addresses Bindings . . . . 8
3.4. Proxy MIPv6 Use Case . . . . . . . . . . . . . . . . . . . 8
3.4.1. Local Mobility Anchor Revokes A PMIPv6 Binding . . . . 8
3.4.2. Local Mobility Anchor Revokes Bulk PMIPv6 Bindings . . 10
3.4.3. Mobile Access Gateway Revokes Bulk PMIPv6 Bindings . . 10
4. Security Model . . . . . . . . . . . . . . . . . . . . . . . . 10
5. Exchanging Binding Revocation Messages over an IPv4
Transport Network . . . . . . . . . . . . . . . . . . . . . . 10
6. Binding Revocation Message . . . . . . . . . . . . . . . . . . 11
6.1. Binding Revocation Indication Message . . . . . . . . . . 12
6.2. Binding Revocation Acknowledgement Message . . . . . . . . 15
7. Binding Revocation Process Considerations . . . . . . . . . . 17
7.1. Sending Binding Revocation Messages . . . . . . . . . . . 17
7.2. Receiving Binding Revocation Messages . . . . . . . . . . 18
7.3. Retransmission of Binding Revocation Indication . . . . . 18
8. Home Agent Operation . . . . . . . . . . . . . . . . . . . . . 19
8.1. Sending Binding Revocation Indication . . . . . . . . . . 19
8.2. Receiving Binding Revocation Acknowledgement . . . . . . . 20
9. Local Mobility Anchor Operation . . . . . . . . . . . . . . . 21
9.1. Binding Revocation Initiator . . . . . . . . . . . . . . . 21
9.1.1. Sending Binding Revocation Indication . . . . . . . . 21
9.1.2. Receiving Binding Revocation Acknowledgement . . . . . 24
9.2. Binding Revocation Responder . . . . . . . . . . . . . . . 24
9.2.1. Receiving Binding Revocation Indication . . . . . . . 24
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9.2.2. Sending Binding Revocation Acknowledgement . . . . . . 25
10. Mobile Access Gateway Operation . . . . . . . . . . . . . . . 26
10.1. Binding Revocation Responder . . . . . . . . . . . . . . . 26
10.1.1. Receiving Binding Revocation Indication . . . . . . . 26
10.1.2. Sending Binding Revocation Acknowledgement . . . . . . 28
10.2. Binding Revocation Initiator . . . . . . . . . . . . . . . 29
10.2.1. Sending Binding Revocation Indication . . . . . . . . 29
10.2.2. Receiving Binding Revocation Acknowledgement . . . . . 30
11. Mobile Node Operation . . . . . . . . . . . . . . . . . . . . 30
11.1. Receiving Binding Revocation Indication . . . . . . . . . 30
11.2. Sending Binding Revocation Acknowledgement . . . . . . . . 32
12. Protocol Configuration Variables . . . . . . . . . . . . . . . 32
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32
14. Security Considerations . . . . . . . . . . . . . . . . . . . 33
15. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 33
16. References . . . . . . . . . . . . . . . . . . . . . . . . . . 33
16.1. Normative References . . . . . . . . . . . . . . . . . . . 33
16.2. Informative References . . . . . . . . . . . . . . . . . . 34
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 34
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1. Introduction
In the case of Mobile IPv6 and for administrative reason, sometimes
it becomes necessary to inform the mobile node that its registration
has been revoked and the mobile node is no longer able to receive IP
mobility service using its Home Address. In some networks where
Mobile IPv4 [RFC3344] has been deployed, a similar Mobile IPv4
registration revocation mechanism has been specified [RFC3543].
This document defines the semantics of the revocation mechanism of a
mobile node registration binding, which could have been established
using a Client Mobile IPv6 or any of its extensions, e.g. Proxy
Mobile IPv6 signaling. The proposed revocation mechanism uses a new
MH type <IANA-TBD> for revocation signaling which is applicable to
Mobile IPv6 [RFC3775] and Proxy Mobile IPv6 [RFC5213] and can be used
by any two IP mobility entities. As an example, this mechanism
allows a local mobility anchor, involved in providing IP mobility
services to a mobile node, to notify the mobile access gateway of the
termination of a mobile node binding registration. In another
example, a mobile access gateway can use this mechanism to notify its
local mobility anchor peer with a bulk termination of all or a subset
of Proxy Mobile IPv6 bindings that are registered with the local
mobility anchor and currently being served by the mobile access
gateway.
2. Conventions & Terminology
2.1. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
2.2. Terminology
All the general mobility related terminology and abbreviations are to
be interpreted as defined in Mobile IPv6 specification [RFC3775] and
Proxy Mobile IPv6 specification [RFC5213].
3. Binding Revocation Protocol and Use Cases Overview
This specification defines a binding revocation mechanism where a
mobility node can communicate to the mobile node or another mobility
node the termination of the mobile node registration binding. The
following subsections describe the protocol overview and applicable
use cases.
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3.1. Binding Revocation Protocol
In the case of Client Mobile IPv6, the revocation procedure can be
initiated by the home agent. If the home network decides to
terminate the service of the mobile node, the home agent sends a
Binding Revocation Indication (BRI) message to the mobile node. The
home agent includes the HoA in the type 2 routing header as specified
in [RFC3775] to indicate the impacted mobile node binding. When the
mobile node receives a BRI message with its HoA included and the
Acknowledge (A) bit is set, the mobile node responds by sending a
Binding Revocation Acknowledgement (BRA) message.
In the case of DSMIPv6 [ID-DSMIP6], the revocation procedure can also
be initiated by the home agent. If the home network decides to
terminate the service of the mobile node, the home agent sends a BRI
message to the mobile node to indicate the termination of the mobile
node IP Mobility service. The home agent may include the HoA option
with the mobile node assigned home IPv4 address. After receiving the
BRI message with the Acknowledge (A) bit is set, the mobile node
responds by sending a BRA message.
Similarly, in the case of Proxy Mobile IPv6 [RFC5213], the revocation
procedure can be initiated by the local mobility anchor by sending a
BRI message to communicate the termination of a mobile node
registration binding to the mobility access gateway. In this case,
the local mobility anchor includes the mobile node Home Network
Prefix option [RFC5213] and the MN-ID option [RFC4283] to indicate to
the mobility access gateway the identity of the PMIPv6 binding that
needs to be terminated. When the mobility access gateway receives
the BRI message with the (A) bit set, the mobility access gateway
responds to the local mobility anchor by sending a BRA message.
On the other hand, the MAG usually sends a de-registration message by
sending a Proxy BU with a lifetime of zero to indicate to the LMA of
the termination of the PMIPv6 mobile node binding registration. In
this case, the MAG includes the MN HNP option, the MN-ID option and
all other required mobility options as per [RFC5213] in order for the
LMA to identify the mobile node PMIPv6 binding. However, in the case
when the mobility access gateway communicates a bulk termination of
PMIPv6 sessions, the MAG sends a BRI message with the (G) and (A)
bits are set and includes the MAG identity in the MN-ID option. When
the LMA receives such BRI message, it ensures that the mobility
access gateway is authorized to send such bulk termination message
and then process the BRI message accordingly. If the local mobility
anchor processes the BRI message successfully and since the (A) bit
is set, the LMA responds to the mobile access gateway by sending the
BRA message. Additionally, the initiator of the binding revocation
procedure includes an indication in the Revocation Trigger field to
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indicate to the receiving node the cause for the revocation
procedure.
3.2. Client MIPv6 and DSMIP6 Use Case
Binding revocation mechanism is applicable to Client Mobile IPv6 and
DSMIPv6 session(s) when the home agent needs to inform the mobile
node that its binding registration has been revoked, e.g. for an
administrative reason. This mechanism enables the home domain to
dynamically allow the user to act upon the revocation message in
order to recover its interrupted mobile IPv6 services.
In this case, the home agent sends a BRI message to indicate to the
mobile node that its current mobile IPv6 binding has been revoked and
it no longer can receive IP mobility service. The home agent
includes the mobile node home address in Type 2 routing header as
used in [RFC3775] and sets the Revocation Trigger field to a proper
value, e.g. Administrative Reason. In the case of DSMIPv6 session,
the home agent may additionally include the mobile node assigned IPv4
Home Address in the IPv4 Home Address Option. When the mobile node
receives the BRI message, it sends a BRA message as described in
Section 11.2 to the home agent. Figure 1 illustrates the message
sequencing when home agent revokes a mobile node binding
registration.
MN HA
| |
| HoA in Type 2 Hdr + BRI [seq.#, A bit] |
|<------------------------------------------|
| |
| |
| |
| HoA in Destination Option BRA[seq.#] |
|------------------------------------------>|
| |
| |
Figure 1: Home Agent Revokes a Mobile Node Binding Registration
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3.3. Multi-Care of Addresses (Monami6) Use Case
In the case of Monami6 protocol, a mobile node is able to register
multiple care-of addresses for the same home address [ID-MCoA].
Binding revocation mechanism is applicable to Monami6 when the HA
sends a BRI message to revoke a single or more care-of address
bindings.
3.3.1. Termination of Multiple Care-of Addresses Bindings
In the case of multiple care-of addresses, the home agent maintains
different binding for each pair of care-of address and home address.
These bindings are also indexed and identified during the mobile node
registration using a Binding ID mobility option [ID-MCoA]. In this
case, the HA may revoke any binding, more than one binding, or all of
the bindings for the same mobile node home address.
In the case when home agent revokes a single binding for a mobile
node with multiple care-of addresses registration, the home agent
sends a BRI message to the mobile node with the corresponding BID
option included and the HoA is in the Type 2 routing header. If the
home agent needs to revoke more than one of the mobile node
registered care-of addresses, the home agent includes all the
corresponding Binding ID options which reference these care-of
addresses in the same BRI message. Figure 2 illustrates the message
flow when the HA revokes two registered Care-of addresses for the
same MN in a single BRI message. The home agent can revoke any
registered binding(s) by sending a BRI message to the respective
mobile node.
HA Binding Cache
================
MN-BID1 [CoA1+HoA]
MN HA MN-BID2 [CoA2+HoA]
| | MN-BID3 [CoA3+HoA]
| BRI [seq.#, A bit, BID1, BID4 options] | MN-BID4 [CoA4+HoA]
|<------------------------------------------|
| |
| |
| |
| BRA [seq.#, Status] |
|------------------------------------------>|
| |
| |
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Figure 2: Home Agent Revokes MN's Specific Care-of Addresses Bindings
3.3.2. Termination of All Care-of Addresses Bindings
The home agent may revoke all of the mobile node registered bindings,
by sending a BRI message without including any BID options while the
HoA is included in the Type 2 header. Figure 1 illustrates the
message flow when the home agent revokes all registered Care-of
addresses bindings for a MN in a single BRI message.
3.4. Proxy MIPv6 Use Case
Since the Mobile node does not participate in the mobility mechanism
in the case of PMIPv6, there are many scenarios where Binding
Revocation mechanism is needed to clean resources and make sure that
the mobility entities, e.g. MAG and LMA, are always synchronized
with respect to the status of the existing proxy mobile IPv6
bindings. The binding revocation mechanism is generic enough that
can be used in all applicable PMIPv6 scenarios and deployment
options. For example, this revocation mechanism is still applicable
and can be used when PMIPv6 is deployed with IPv6 or IPv4 transports
and when the mobile node uses IPv4 or IPv6 address as specified in
[ID-PMIP6-IPv4].
When the MAG receives a BRI message as in Section 10.1.1, the MAG
sends a BRA message to the LMA following the rules described in
Section 10.1.2. Similarly if the LMA receives a BRI message with the
(A) bit is set, the LMA responds to the MAG by sending a BRA message.
3.4.1. Local Mobility Anchor Revokes A PMIPv6 Binding
The local mobility anchor may send a BRI message to the mobile access
gateway, hosting a specific proxy mobile IPv6 binding, with the
appropriate value in the revocation trigger field to indicate that
the mobile node binding has been terminated and the MAG can clean up
the applicable resources. When the MAG receives a BRI message, the
MAG identify the respected binding and if the (A) bit was set in the
received BRI message, the MAG sends a BRA message to the LMA. In
this case, the MAG could send a Router Advertisement message to the
MN with the home network prefix lifetime set to zero.
As an example, Figure 3, illustrates the message sequence for
revoking a mobile node binding at the source MAG during the MN inter-
MAG handoff. During the inter-MAG handoff, the mobile node moves
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from the source MAG to the target MAG. The target MAG sends a PBU
with the new care-of-address to the LMA to update the mobile node
point of attachment. Since the MN binding at the LMA points to the
source MAG and upon receiving the PBU from the target MAG, LMA
updates the MN BCE and send a PBA to the target MAG. LMA can send a
BRI message with the appropriate revocation trigger value, e.g.
inter-MAG handoff - same Access Types, to the source MAG in order to
clean up the applicable resources reserved for the specified MN
binding. The MAG acknowledges the BRI message by sending a BRA
message to indicate the success or failure of the termination of the
mobile node binding.
The process identified above can also be used by the LMA in scenarios
other than the inter-MAG handoff with the proper revocation trigger
value to indicate to the peer MAG that a specific proxy mobile IPv6
binding or bindings have been revoked.
sMAG tMAG LMA
| | |
| | PBU |
| |--------------------------->|
| | PBU triggers
| | BRI Msg to sMAG
| | |
| | PBA |
| |<---------------------------|
| | |
| | |
| BRI [seq.#, R. Trigger, P, A bits, NAI] |
|<-----------------------------------------|
| | |
| | |
| | |
| | |
| BRA [seq.#, Status, P bit] |
|----------------------------------------->|
| | |
| | |
Figure 3: LMA Revokes a MN Registration During Inter-MAG Handoff
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3.4.2. Local Mobility Anchor Revokes Bulk PMIPv6 Bindings
The LMA sends a BRI message to indicate that all bindings which are
hosted by the peer MAG and registered with the LMA are being revoked
by setting the (G) bit as described in Section 9.1.1.
3.4.3. Mobile Access Gateway Revokes Bulk PMIPv6 Bindings
The mobile access gateway sends a BRI message with the (G) bit is set
to indicate that all mobility bindings which are registered at the
LMA and attached to the MAG are being revoked as in Section 10.2.1.
When the LMA receives a BRI message with the (G) bit is set from a
specified MAG, the LMA checks if the MAG is authorized to use global
revocations and responds with the appropriate status code by sending
a BRA message as in Section 9.2.2.
4. Security Model
The binding revocation protocol described here uses the same security
association between the MN and the HA or the MAG and the LMA that has
been used to exchange the corresponding Client MIPv6 or Proxy MIPv6
BU and BA when the mobile node binding was created. If IPsec is
used, the traffic selectors associated with the SP protecting BU and
BA MUST be extended to include Binding Revocation Signaling MH type
<IANA-TBD>. Extending the traffic selectors of the SP in order to
reuse the SA protecting BU and BA (instead of creating new ones)
ensures that those SA will be up and running when the revoking entity
needs to send a Binding Revocation Signaling message.
Additionally, in the case when the LMA receives a BRI which indicates
a bulk termination, i.e., the (G) bit is set, the LMA MUST verify
that the MAG sending the binding revocation indication message is
authorized to invoke Global revocation.
5. Exchanging Binding Revocation Messages over an IPv4 Transport
Network
In some deployments, the network between the MAG and the LMA may only
support IPv4 transport. In this case, the Binding Revocation
messages (BRI and BRA) are tunneled over IPv4. If the Proxy Binding
Update and Proxy Binding Acknowledgment messages are sent using UDP
encapsulation to traverse NATs, then the Binding Revocation messages
are sent using the same UDP encapsulation. The same UDP port that
was used for the Proxy Binding Update and Proxy Binding
Acknowledgement messages will also be used when transporting Binding
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Revocation messages over IPv4 using UDP encapsulation. For more
details on tunneling Proxy Mobile IPv6 signaling messages over IPv4,
see [ID-PMIP6-IPv4].
6. Binding Revocation Message
This section defines the Binding Revocation Message format using a MH
Type <IANA-TBD> as illustrated in Figure 4. The value in the Binding
Revocation Type field defines whether the Binding Revocation message
is a BRI or BRA. If the Binding Revocation type field is set to 1,
the Binding Revocation Message is a Binding Revocation Indication
message as in Section 6.1. However, if the value is 2, it is a
Binding Revocation Acknowledgement message as in Section 6.2.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload Proto | Header Len | MH Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Checksum | B.R. Type | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
. Binding Revocation Message Data .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Binding Revocation Message
Binding Revocation Type
8-bit unsigned integer. It defines the type of Binding Revocation
Message. It can be assigned one of the following values:
0 Reserved
1 Binding Revocation Indication Message
2 Binding Revocation Acknowledgement Message
All other values are reserved
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Binding Revocation Message Data
The Binding Revocation Message Data follows the Binding Revocation
Message format that is defined in this document for the specified
value in the Binding Revocation Type field. It is either a BRI as
in Section 6.1 or BRA as in Section 6.2.
6.1. Binding Revocation Indication Message
The Binding Revocation Indication (BRI) message is a Binding
Revocation Message which has a MH type <IANA-TBD> and a Binding
Revocation Type value of 1. It is used by the revoking mobility node
to inform the receiving mobility entity that the IP mobility service
of a specific binding or bindings have been revoked. Binding
Revocation Indication message is sent as described in Section 8.1,
Section 9.1.1, and Section 10.2.1.
When the value 1 is indicated in the B. R. type field of the Binding
Revocation Message, the format of the Binding Revocation Message Data
follows the Binding Revocation Indication message as in Figure 5
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| B.R. Type = 1 | R. Trigger |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence # |P|A|V|G| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Mobility options .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Binding Revocation Indication Message
Revocation Trigger
8-bit unsigned integer indicating the event which triggered the
revoking node to send the BRI message. The following Revocation
Trigger values are currently defined:
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0 Reserved
1 Unspecified
2 Administrative Reason
3 Inter-MAG Handoff - same Access Types
4 Inter-MAG Handoff - different Access Types
5 Inter-MAG - Unknown Handoff
6 Per-Peer Policy
7 Revoking Node Local Policy
8 User Initiated Session(s) Termination
9 Access Network Session(s) Termination
10 IPv4 HoA Lease Expires
11 Possible Out-of Sync BCE State
250-255 Reserved For Testing Purposes only
All other values are Reserved
Sequence #
A 16-bit unsigned integer used by the sending mobility node to
match a returned Binding Revocation Acknowledgement with this
Binding Revocation Indication.
Proxy Binding (P)
The Proxy Binding (P) bit is set by the sending mobility node to
indicate that the revoked binding(s) is a proxy MIPv6 binding.
Acknowledge (A)
The Acknowledge (A) bit is set by the sending mobility node, e.g.
LMA, HA, or MAG, to request a Binding Revocation Acknowledgement
be returned upon receipt of the Binding Revocation Indication as
in Section 8.1, Section 9.1.1, and Section 10.2.1.
IPv4 HoA Binding Only (V)
The IPv4 HoA Binding Only (V) bit is set by the sending mobility
node, HA or LMA, to request the receiving mobility entity the
termination of the IPv4 Home Address binding only as in
Section 8.1, and Section 9.1.1.
Global (G)
The Global (G) bit is set by the sending mobility node, LMA or
MAG, to request the termination of all Per-Peer mobility Bindings
or Multiple Bindings which share a common identifier that are
served by the sending and receiving mobility entities as in
Section 9.1.1 and Section 10.2.1.
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Reserved
These fields are unused. They MUST be initialized to zero by the
sender and MUST be ignored by the receiver.
Mobility Options
Variable-length field of such length that the complete Mobility
Header is an integer multiple of 8 octets long. This field
contains zero or more TLV-encoded mobility options. This document
does not define any new mobility option. The receiver MUST ignore
and skip any options which it does not understand. These mobility
option(s) are used by the receiving mobility entity to identify
the specific binding or bindings that the sending mobility entity
requesting to be revoked.
The following options are valid in a Binding Revocation Indication:
o Home Network Prefix option [RFC5213]. This option MAY be used
when the (P) bit is set. This option MUST be present when the BRI
is used to revoke a single PMIP binding cache entry.
o Mobile Node Identifier Option [RFC4283]. This option is mandatory
when the (P) bit is set. Additionally, If the (G) bit is set by
the mobile access gateway, this option carries the MAG identity.
o Binding ID mobility option [ID-MCoA]. This option is mandatory if
the sending mobility entity request to terminate one binding of a
multi care-of addresses bindings for the same mobile node. The
sending mobility entity may include more than one of the Binding
ID mobility options.
o IPv4 Home Address option which contains the mobile node home IPv4
address [ID-DSMIP6]. This option is included only when the IPv4
HoA Binding only (V) bit is set.
o Alternate Care-of Address mobility option [RFC3775]. This option
MAY be included to indicate the Care-of Address of the mobile
node's binding that is being revoked. In the case when the Global
(G) bit set, this option identifies all the mobility bindings that
share the same care-of address. Additionally, if the Global (G)
bit set, more than one Alternate Care-of Address mobility options
MAY be present in the BRI message.
If no options are present in this message, 4 octets of padding are
necessary and the Header Len field of the Binding Revocation Message
will be set to 1.
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6.2. Binding Revocation Acknowledgement Message
The Binding Revocation Acknowledgement (BRA) message is a Binding
Revocation Message which has a MH type <IANA-TBD> and a Binding
Revocation Type value of 2. It is used to acknowledge the receipt of
a Binding Revocation Indication message described in Section 6.1.
This packet is sent as described in Section 9.2.2, Section 10.1.2,
and Section 11.2.
When the value 2 is indicated in the Binding Revocation type field of
the Binding Revocation Message, the format of the Binding Revocation
Message Data follows the Binding Revocation Acknowledgement message
as in Figure 6
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| B.R. Type = 2 | Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence # |P|V|G| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Mobility options .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Binding Revocation Acknowledgement Message
Status
8-bit unsigned integer indicating the result of processing the
Binding Revocation Indication message by the receiving mobility
entity. The following status values are currently defined.
0 success
1 partial success
128 Binding Does NOT Exist
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129 IPv4 HoA Binding Does NOT Exist
130 IPv4 HoA Option Required
131 Global Revocation NOT Authorized
132 CAN NOT Identify Binding
133 Revocation Failed, MN is Attached
Sequence #
The sequence number in the Binding Revocation Acknowledgement is
copied from the Sequence Number field in the Binding Revocation
Indication. It is used by the revoking mobility entity, e.g. HA,
LMA, in matching this Binding Revocation Acknowledgement with the
outstanding BRI.
Proxy Binding (P)
The Proxy Binding (P) bit is set if the (P) bit is set in the
corresponding Binding Revocation Indication message.
IPv4 HoA Binding Only (V)
The IPv4 HoA Binding Only (V) bit is set if the (V) bit is set in
the corresponding BRI message.
Global (G)
The Global (G) bit is set if the (G) bit is set in the
corresponding BRI message.
Reserved
These fields are unused. They MUST be initialized to zero by the
sender and MUST be ignored by the receiver.
Mobility Options
Variable-length field of such length that the complete Mobility
Header is an integer multiple of 8 octets long. This field
contains zero or more TLV-encoded mobility options. In the case
when the Status field is set to success, no mobility option is
required. The mobility option(s) is usually used to communicate
information of the bindings that failed the revocation procedure.
The following options are valid in a Binding Revocation
Acknowledgement:
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o Home Network Prefix option [RFC5213]. This option MAY be included
when the (P) bit is set.
o Mobile Node Identifier Option [RFC4283]. This option MAY be
included when the (P) bit is set. This option SHOULD be included
if the Home Network Prefix option is included.
o Binding ID mobility option [ID-MCoA]. This option MAY be included
to indicate the specific Binding ID that the receiving node failed
to revoke.
If no options are present in this message, 4 octets of padding are
necessary and the Header Len field of the Binding Revocation Message
will be set to 1.
7. Binding Revocation Process Considerations
The following subsections describe the details of the binding
revocation generic process by the different mobility entities.
7.1. Sending Binding Revocation Messages
When sending a Binding Revocation message, the sending mobility node,
initiator, follows the rules of constructing a Mobility Header as in
Section 9.2 of [RFC3775] with the exception of setting the MH Type
field to <IANA-TBD and the appropriate value of the Binding
Revocation Type field.
The mobility entity which initiates the revocation process,
initiator, MUST use the underlying IPsec security association that
has been used during the mobile node binding registration to secure
the BRI and BRA messages transmission with the responding mobility
entity, responder.
When a mobility entity initiate the binding revocation process by
sending a Binding Revocation Indication message, the initiator MUST
construct the BRI message as described in Section 6.1. In the BRI
message, the initiator MUST set the Sequence Number field to the next
sequence number available for Binding Revocation. Since sending BRI
messages is not done on a regular basis, a 16 bit sequence number
field is large enough to allow the initiator to match the BRA to the
outstanding BRI with (A) bit set using the sequence number field
only.
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On the other hand, when the responder acknowledge the BRI message by
sending a BRA, the responder MUST construct the Binding Revocation
Acknowledgement as described in Section 6.2. In this case, the
responder MUST set the Sequence Number field by copying the value
from the Sequence Number field of the received Binding Revocation
Indication. Additionally, it MUST set the status field to a valid
value that reflects the processing of the received Binding Revocation
Indication.
7.2. Receiving Binding Revocation Messages
When receiving a Binding Revocation message, the receiving mobility
node MUST verify the Mobility Header as in [RFC3775]. If the packet
is dropped due to failing any of the Mobility Headers test check, the
receiving node MUST follow the processing rules as in Section 9.2 of
[RFC3775]. For example, it MUST send a Binding Error message with
the Status field set to 2 (unrecognized MH Type value) if it does not
support the received binding revocation message type.
Since some mobility entities, e.g. LMA and MAG, are allowed to
receive and possibly send a BRI or a BRA for different cases, IPsec
mechanism will prevent any possible man in the middle reflection
attack.
Upon receiving a packet carrying a Binding Revocation Indication, the
receiving mobility entity, responder, validates that the packet was
received protected with the underlying IPsec protection with the
responding mobility entity.
Upon receiving a packet carrying a Binding Revocation
Acknowledgement, the receiving mobility entity, initiator, MUST
validate that Sequence Number field matches the Sequence Number of an
outstanding Binding Revocation Indication that was sent by the
initiator. If the Sequence Number does not match any sequence number
of any of the outstanding BRI, the receiving node MUST ignore the
message but MAY log the event.
7.3. Retransmission of Binding Revocation Indication
If the sending mobility entity does not receive a Binding Revocation
Acknowledgement in response to the outstanding Binding Revocation
Indication before the MINDelayBRIs timer expires, the mobility
entity, e.g. LMA, may retransmit the same BRI message up to the
BRIMaxRetriesNumber as defined in Section 12. If the revoking
mobility entity does not receive a BRA message after the maximum
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number of retransmits have been sent, the revoking mobility entity
can clean the mobile node binding cache and all resources associated
with this binding. The revoking mobility entity may log the event.
8. Home Agent Operation
8.1. Sending Binding Revocation Indication
When an event requires the home agent to terminate a mobile node
mobile IPv6 registration, e.g. for administrative reason, the home
agent sends a Binding Revocation Indication message to the mobile
node to inform the mobile node that its specified binding has been
revoked and it will no longer be able to receive an IP connectivity
via its binding with the home agent.
To terminate a mobile node registration and its current binding with
the home agent, the home agent sends a packet to the mobile node
containing a Binding Revocation Indication, with the packet
constructed as follows:
o The Acknowledge (A) bit MAY be set in the BRI to request the
mobile node to send a Binding Revocation Acknowledgement upon
receipt of the BRI.
o The Revocation Trigger field MUST be set in the Binding Revocation
Indication to indicate to the mobile node the reason for revoking
its IP mobility binding with the home agent. The Revocation
Trigger may be used by the mobile node to take further steps if
necessary.
o The Binding Revocation Indication MUST be sent using a type 2
routing header which contains the mobile node's registered IPv6
home address for the binding being revoked.
o The care-of address for the binding MUST be used as the
destination address in the packet's IPv6 header, unless an
Alternate Care-of Address mobility option is included in the
Binding Revocation Indication.
o If the home agent needs to only revoke the mobile node's IPv4 home
address binding, the home agent MUST set the IPv4 HoA Binding Only
(V) bit and MUST include the mobile node's registered IPv4 home
address that is being revoked in the IPv4 Home Address option.
The Acknowledge (A) bit in the Binding Revocation Indication requests
the mobile node to return a Binding Revocation Acknowledgement in
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response to this Binding Revocation Indication. As described in
Section 7.3, the home agent SHOULD retransmit this Binding Revocation
Indication to the mobile node before terminating its IP connection
until it receives a matching Binding Revocation Acknowledgement or
the BRIMaxRetransmitNumber has been reached.
When the home agent sends a BRI to the mobile node with the (A) bit
set, the home agent sets a flag in the mobile node BCE to indicate
that revocation is in progress and starts the MINDelayBRIs timer.
The home agent maintains the mobile node BCE in this state until it
receives a Binding Revocation Acknowledgement or the
BRIMaxRetransmitNumber is reached.
In a race condition case, the home agent may receive a BU from the
mobile node while the mobile node's BCE has the revocation in
progress flag set, the home agent should handle this case based on
the reason for sending the Binding Revocation Indication message and
its local policy. In this case, if the home agent accepts the BU, it
needs to update the mobile node BCE accordingly, e.g. removing the
revocation in progress flag.
When the home agent needs to revoke one or more of a mobile node
bindings that were created using Multi Care-of address registration
as in [ID-MCoA], the home agent MUST include all the related Binding
ID options that identify these bindings in the Binding Revocation
Indication message. In the case when the home agent needs to revoke
all of the mobile node bindings, the home agent MUST NOT include any
of the Binding ID options.
The home agent MUST use the IPsec security association that has been
used during the MIPv6 binding registration with the HA to secure the
BRI and BRA messages transmission with the mobile node.
8.2. Receiving Binding Revocation Acknowledgement
When the home agent receives a packet carrying a valid BRA that was
successfully processed as in Section 7.2, the home agent SHOULD
examine the Status field as follows:
o If the Status field indicates that the Binding Revocation
Indication was processed successfully, the home agent deletes the
MINDelayBRIs timer and the mobile node bindings and all related
resources.
o If the Status field indicates any value other than success, the
home agent SHOULD examine any mobility options included in the
Binding Revocation Acknowledgement. The home agent MAY log the
appropriate event to reflect the status of the received BRA.
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9. Local Mobility Anchor Operation
9.1. Binding Revocation Initiator
9.1.1. Sending Binding Revocation Indication
When an event requires the local mobility agent to terminate a mobile
node proxy mobile IPv6 registration, e.g. for administrative reason
or inter-MAG handover, the local mobility agent sends a Binding
Revocation Indication message to the mobile access gateway which host
the mobile node proxy CoA to indicate that the mobile node's
specified binding should be removed. It also indicate that the LMA
will no longer maintain a tunnel for this mobile node binding which
points to the mobile node proxy CoA that is hosted at this MAG.
To terminate a mobile node proxy mobile IPv6 registration and its
current PMIPv6 binding with the local mobility agent, the LMA sends a
packet to the MAG containing a BRI message following the procedure in
Section 7.1 and the following rules:
o The Acknowledge (A) bit MAY be set in the Binding Revocation
Indication to request the mobile access gateway to send a Binding
Revocation Acknowledgement upon receipt of the BRI.
o The Proxy Mobile IP (P) bit MUST be set in the BRI message to
indicate that the binding being revoked is a proxy Mobile IPv6
binding.
o The Revocation Trigger field MUST be set in the Binding Revocation
Indication to indicate to the mobile access gateway the reason for
removing the specified mobile node proxy mobile IPv6 binding at
the LMA. The Revocation Trigger may be used by the mobile access
gateway to learn the mobile node's latest movement.
o In case of revoking all Per-Peer bindings, the Global (G) bit MUST
be set and the Revocation Trigger MUST contain a value of "Per-
Peer Policy" in the Binding Revocation Indication to request the
mobile access gateway to remove all Per-Peer bindings that are
registered with the LMA and hosted at this MAG.
o Whenever the Global (G) bit is set in the BRI, the Acknowledge (A)
bit MUST be set to request the mobile access gateway to send a
Binding Revocation Acknowledgement upon receipt of the BRI.
o The packet MUST contain the Mobile Node Identifier, MN-ID, option
which contains the mobile node's NAI that was used in the proxy
Binding Update during the mobile node registration.
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o If the Mobile Node Identifier, MN-ID, is registered in more than
one of the mobile node's BCE and the LMA does NOT need to revoke
all of the mobile node's bindings, the packet MUST contain another
identifier to uniquely identify the mobile node binding(s) that is
being revoked, e.g., at least one Home Network Prefix option which
contains the mobile node's registered HNP for the binding being
revoked.
o The care-of address for the binding MAY be used as the destination
address in the packet's IPv6 header, unless an Alternate Care-of
Address mobility option is included in the Binding Revocation
Indication message.
The Acknowledge (A) bit in the Binding Revocation Indication requests
the mobile access gateway to return a Binding Revocation
Acknowledgement in response to this Binding Revocation Indication.
As described in Section 7.3, the LMA SHOULD retransmit this BRI to
the MAG before deleting the mobile node IP tunnel to the mobile
access gateway until it receives a matching Binding Revocation
Acknowledgement or the BRIMaxRetransmitNumber is reached. The local
mobility anchor MAY delete the mobile node(s) IP tunnel immediately
after sending the Binding Revocation Indication and before receiving
the BRA message.
When the local mobility anchor sends a Binding Revocation Indication
to the mobile access gateway to remove a specific binding and the
Acknowledge (A) bit is set in the BRI, the local mobility anchor sets
a flag in the mobile node proxy BCE to indicate that revocation is in
progress and starts the MINDelayBRIs timer. The local mobility
anchor SHOULD maintain the mobile node proxy BCE in this state until
it receives a Binding Revocation Acknowledgement or the
BRIMaxRetransmitNumber is reached. In the case when the local
mobility anchor sets the Revocation Trigger field to a value which
indicate inter-MAG handover, the local mobility anchor MAY switch the
mobile node IP tunnel to the target mobile access gateway before
sending a Binding Revocation Indication to the sources mobile access
gateway.
In a race condition case, the local mobility anchor may receive a PBU
from the mobile access gateway while the mobile node's proxy BCE has
the revocation in progress flag set, the LMA should handle this case
based on the reason for sending the Binding Revocation Indication
message and its local policy. In this case, if the LMA accepts the
PBU, it needs to update the mobile node proxy BCE accordingly, e.g.
removing the revocation in progress flag.
When the local mobility anchor needs to revoke all mobile nodes proxy
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BCE that are registered with the local mobility anchor and hosted at
the mobile access gateway, the LMA MUST set the Global (G) bit and
the value of the Revocation Trigger field to "Per-Peer Policy". In
this case, the LMA MUST NOT include any mobility options in the BRI.
When the LMA needs to revoke all mobile nodes proxy BCE that belong
to a specific realm, e.g. @companyabc.com, and are registered with
the LMA and hosted at the MAG, the local mobility anchor MUST set the
Global (G) bit and the value of the Revocation Trigger field to
"Revoking Node Local Policy". In this case, the local mobility
anchor MUST include a mobility option to identify the impacted
bindings, e.g. MN-ID option with a wildcard NAI, e.g.
*@companyabc.com, to identify all the mobile nodes BCEs that need to
be removed.
When the mobile node is registered with multiple Home Network
Prefixes for the same proxy care-of address, the local mobility
anchor SHOULD include a HNP option for each registered HNP in the
BRI. Alternatively, the LMA MAY include only the mobile node
identifier, MN-ID, option in the BRI to indicate to the mobile access
gateway to remove all bindings of the specified mobile node NAI in
the MN-ID option.
When the mobile node is registered with an IPv4 proxy home address in
addition to the Home Network Prefix where both of the IPv4 pHoA and
HNP are bound to the same proxy CoA, the local mobility anchor MAY
revoke the mobile node IPv4 proxy HoA binding to the current mobile
node proxy CoA while maintaining the mobile node binding of the HNP
to its current pCoA as part of the mobile node BCE. In this case, if
the LMA decides to revoke the mobile node IPv4 proxy HoA ONLY, the
LMA MUST send a BRI message following the procedure in Section 7.1
and the following rules:
o The Acknowledge (A) bit MUST be set in the BRI to request the MAG
to send a BRA message.
o The IPv4 HoA Binding Only (V) bit MUST be set in the BRI to
indicate that only the IPv4 home address binding is being revoked.
o The IPv4 Home Address option MUST be included with the mobile
node's registered IPv4 home address that is being released in
addition to the MN-ID option.
o The mobile node Home Network Prefix option MUST NOT be included.
o The Revocation Trigger field MUST be set to an appropriate value,
e.g. "IPv4 Address Lease Expired".
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9.1.2. Receiving Binding Revocation Acknowledgement
When the local mobility anchor receives a packet carrying a valid
Binding Revocation Acknowledgement that was successfully processed as
in Section 7.2 and if the mobile node BCE is in the state of
Revocation in progress, the local mobility anchor SHOULD examine the
Status field before clearing the mobile node related resources as
follows:
o If the Status field indicates that the BRI was processed
successfully, the local mobility anchor delete the MINDelayBRIs
timer and the mobile node proxy bindings and all associated
resources.
o If the Status field indicates partial success value or MN binding
does not exist, the local mobility anchor SHOULD examine mobility
options that are included in the Binding Revocation
Acknowledgement, if any, before deleting the MINDelayBRIs timer
and the mobile node associated proxy bindings and all related
resources. It is based on the LMA local policy how to handle the
mobile node BCE(s) that the mobile access gateway indicated it
failed the revocation procedure, however, the LMA MAY log the
event.
9.2. Binding Revocation Responder
9.2.1. Receiving Binding Revocation Indication
When the local mobility anchor receives a packet carrying a Binding
Revocation Indication that was successfully processed as in
Section 7.2, the local mobility anchor SHOULD in addition process the
message as follows:
o Binding Revocation Indication is formatted as in Section 6.1 and
if the (P) bit is set, the local mobility anchor MUST validate
that all impacted binding(s) have the proxy binding flag set.
o If the Global (G) bit is set, the Proxy (P) bit MUST be set and
the BRI SHOULD contain the mobile access gateway ID in the MN-ID
option. The local mobility anchor MUST verify that the identified
mobile access gateway as per the value in the MN-ID option is
authorized to use the Per-Peer Global bindings revocation. The
mechanism the LMA uses to verify the MAG authorization is out of
scope of this document.
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o If the Global (G) bit is set and only the mobile node identifier,
MN-ID, option is included, the local mobility anchor MUST revoke
all mobile nodes bindings which proxy CoA is the one used as the
source of the IPv6 packet that carried the BRI. However, if one
or more Alternate Care-of Address options are included in addition
to the mobile node identifier option in the BRI message, the local
mobility anchor MUST revoke all mobile nodes bindings which proxy
Care-of Address is one of the Care-of.
o The LMA identifies all impacted mobile nodes bindings and if the
Acknowledgement (A) bit is set, the local mobility anchor MUST
send a Binding Revocation Acknowledgement following Section 9.2.2
using the appropriate status code.
o If the Global (G) bit is NOT set, the local mobility anchor MUST
use the included mobility options to identify the impacted mobile
node binding as follows:
1. If only the mobile node identifier, MN-ID, option is included,
the local mobility anchor MUST revoke all bindings for this
mobile node which use the specified mobile node NAI.
2. If the mobile node identifier, MN-ID, and the Home Network
Prefix option are included, the local mobility anchor MUST
only remove the specified proxy binding.
3. If the mobile node identifier, MN-ID, option and more than one
Home Network Prefix options are included, the local mobility
anchor MUST remove all bindings which are referenced by these
multiple Home Network Prefixes for the specified mobile node
NAI.
The Revocation Trigger field value in the received Binding Revocation
Indication could be used by the local mobility anchor to log an event
or update some local parameters which tracks the state of the peer
mobile access gateway.
9.2.2. Sending Binding Revocation Acknowledgement
When the local mobility anchor receive a valid Binding Revocation
Indication with the (A) bit set and after processing the BRI message,
the local mobility anchor sends a packet to the mobile access gateway
containing a Binding Revocation Acknowledgement following the process
in Section 7.1 and the following:
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o If the (P) bit was set in the received Binding Revocation
Indication, the local mobility anchor MUST set the (P) bit in the
BRA.
o If the Global (G) bit was set in the received BRI, the local
mobility anchor MUST set the (G) bit in the Binding Revocation
Acknowledgement.
o If the IPv4 HoA Binding Only (V) bit was set in the received BRI,
the local mobility anchor MUST set the (V) bit in the Binding
Revocation Acknowledgement.
o The local mobility anchor MUST set the status field to a valid
code that reflects the processing of the received Binding
Revocation Indication. If the mobile access gateway is not
authorized to use the Per-Peer Global revocation feature, the LMA
MUST set the status field to (Global Revocation NOT Authorized).
o In the case that one of the bindings identified in the received
BRI message has already been released before receiving the BRI,
the LMA MAY set the status field to partial success and in this
case it MAY include the mobile node identifier or the Home Network
Prefix option to identify the binding(s) that failed revocation.
o The destination IP address of the IPv6 packet of the Binding
Revocation Acknowledgement is set to the source IP address of the
received BRI.
10. Mobile Access Gateway Operation
10.1. Binding Revocation Responder
10.1.1. Receiving Binding Revocation Indication
Upon receiving a packet carrying a Binding Revocation Indication, the
mobile access gateway MUST validate the packet according to
Section 7.2 and the following:
o BRI MUST be formatted as in Section 6.1 and the (P) bit is set.
o If the Acknowledgement (A) bit in the received BRI is set, the
mobile access gateway MUST send a Binding Revocation
Acknowledgement following Section 10.1.2 using the appropriate
status value.
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o If the Global (G) bit is set and the Revocation Trigger field is
set to "Per-Peer policy", the mobile access gateway identifies all
bindings that are registered at the LMA and hosted at the MAG.
This Binding Revocation Indication does not include any other
mobility options. In this case, the MAG MUST send a BRA with the
appropriate status code to the LMA.
o If the Global (G) bit is set and the Revocation Trigger field is
set to "Revoking Node Local Policy", the MAG MUST identify all
bindings that are registered at the LMA and hosted at the MAG
using the mobility option(s) included in the BRI. This Binding
Revocation Indication SHOULD include at least the MN-ID option,
e.g. with a wild card NAI. In this case, the MAG MUST send a BRA
with the appropriate status code to the LMA.
o If the Global (G) bit is set and the Revocation Trigger field is
set to "Revoking Node Local Policy", and no mobility options are
included in the Binding Revocation Indication message or the MAG
is not able to identify the impacted mobile nodes bindings based
on the included mobility options, the MAG MUST treat this as an
error scenario. In this case, the MAG SHOULD send a Binding
Revocation Acknowledgement message with status "CAN NOT Identify
Binding".
o If the Revocation Trigger field value in the received Binding
Revocation Indication message indicates an inter-MAG handover and
the (A) bit is set, the MAG use the mobility option(s) included in
the BRI message to identify the mobile node binding. The mobile
access gateway MAY validate that the mobile node is no longer
attached to the mobile access gateway before sending a successful
Binding Revocation Acknowledgement message to the LMA. However,
if the Revocation Trigger field is set to "Inter-MAG - Unknown
Handoff" and the (A) bit is set, the MAG MUST validate that the
mobile node is no longer attached to the MAG before sending a
successful BRA message and deleting the resources associated with
the mobile node binding. Otherwise, if the MAG verified that the
MN is still attached, the MAG MUST set the status field in the BRA
to "Revocation failed - MN is attached".
o If the IPv4 HoA Binding Only (V) bit in the received BRI message
is set, the MAG uses the MN-ID option to identify the mobile node
binding entry in the BUL. The MAG MUST verify that the IPv4
address included in the IPv4 Home Address option in the received
BRI is the same as the IPv4 proxy HoA that is assigned to the
mobile node. After the MAG successfully validates the received
IPv4 home address as the mobile node IPv4 HoA, the MAG MUST
consider this as an indication to release the mobile node IPv4
proxy HoA binding to the mobile node current proxy CoA ONLY.
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Consequently, the MAG MUST continue to maintain the mobile node
IPv6 proxy HoA or HNP binding to the current mobile node proxy CoA
as part of the mobile node binding in the BUL entry and release
all resources associated with the MN IPv4 proxy HoA binding to the
MN pCoA. In this case, the MAG MUST send a BRA message with the
status field is set to success. On the other hand, if the MAG is
able to identify the mobile node binding using the MN-ID but
failed to identify the received IPv4 proxy HoA, the MAG MUST send
a BRA with status field is set to "IPv4 HoA Binding Does NOT
Exist".
The Revocation Trigger field value in the received BRI could be used
by the mobile access gateway to define what actions the MAG could do
to inform the mobile node that its IP connectivity to the current HNP
has been terminated. e.g. if the Revocation Trigger field is set to
"Administrative Reason", the mobile access gateway may send a RA
message after setting the Home Network Prefix lifetime to zero.
10.1.2. Sending Binding Revocation Acknowledgement
When the mobile access gateway receive a valid Binding Revocation
Indication with the (A) bit set and after processing the BRI message,
the mobile access gateway sends a packet to the local mobility anchor
containing a Binding Revocation Acknowledgement according to the
procedure in Section 7.1 and the following:
o The mobile access gateway MUST set the (P) bit in the Binding
Revocation Acknowledgement if it is set in the received BRI.
o If the Global (G) bit was set in the received BRI, the mobile
access gateway MUST set the (G) bit in the Binding Revocation
Acknowledgement.
o If the IPv4 HoA Binding Only (V) bit was set in the received BRI,
the mobile access gateway MUST set the (V) bit in the Binding
Revocation Acknowledgement.
o The mobile access gateway MUST set the status field to a valid
code that reflects the processing of the received Binding
Revocation Indication.
o In the case that one or more of the bindings identified in the
received BRI message has already been released before receiving
the BRI, the mobile access gateway MAY set the status field to
partial success and in this case it MAY include the mobile node
identifier, MN-ID, or the Home Network Prefix option to identify
the binding(s) that failed to be removed as part of the revocation
procedure.
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o The destination IP address of the IPv6 packet of the Binding
Revocation Acknowledgement is set to the source IP address of the
received Binding Revocation Indication.
10.2. Binding Revocation Initiator
10.2.1. Sending Binding Revocation Indication
The mobile access gateway could send a Binding Revocation Indication
message to indicate the termination of multiple mobile node bindings,
e.g., when using the global revocation with the Global (G) bit is
set. In this case when an event occurs which requires the mobile
access gateway to inform the LMA to terminate all mobile nodes
bindings that are registered at the local mobility anchor and the
mobile access gateway, the mobile access gateway sends a Binding
Revocation Indication message following Section 7.1 and the
following:
o The Acknowledge (A) bit MUST be set in the Binding Revocation
Indication to request the local mobility anchor to send a Binding
Revocation Acknowledgement upon receipt of the BRI.
o The Proxy Mobile IP (P) bit MUST be set in the Binding Revocation
Indication to indicate that bindings that being revoked is a proxy
Mobile IPv6 binding.
o The Global (G) bit MUST be set and the Revocation Trigger contains
a value of "Per-Peer Policy" in the Binding Revocation Indication
to request the LMA to remove all Per-Peer bindings that are
registered with the LMA and hosted at this MAG. In this case, the
MN-ID option MUST be included in the BRI and contains the mobile
access gateway identity. In this case the mobile access gateway
MAY include one or more Alternate Care-of Address option(s). The
Alternate Care-of Address option(s) include the proxy Care-of
address(es) which their bindings are being impacted by this BRI
message.
o The mobile access gateway address MAY be used as the Source
Address in the packet's IPv6 header.
The Acknowledge (A) bit in the Binding Revocation Indication requests
the local mobility anchor to return a BRA in response to this Binding
Revocation Indication. As described in Section 7.3, the mobile
access gateway SHOULD retransmit this BRI to the local mobility
anchor until it receives a matching BRA or the BRIMaxRetransmitNumber
is reached. The mobile access gateway MAY delete the mobile nodes IP
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tunnels immediately after sending the Binding Revocation Indication
before receiving a BRA message from the LMA.
10.2.2. Receiving Binding Revocation Acknowledgement
When the mobile access gateway receives a packet carrying a valid
Binding Revocation Acknowledgement that was successfully processed
according to Section 7.2, the mobile access gateway MUST process the
BRA as per the followings:
o When the mobile access gateway receives a packet carrying a valid
Binding Revocation Acknowledgement and the Global (G) and Proxy
MIPv6 (P) bits are set and the mobile nodes BCEs are in the state
of Revocation in Progress, the mobile access gateway SHOULD
examine the Status field as follows:
o If the Status field indicates that the Binding Revocation
Indication was processed successfully, the mobile access gateway
delete the MINDelayBRIs timer and the mobile nodes proxy bindings
and all associated resources.
o If the Status field indicates (Global Revocation NOT Authorized),
the mobile access gateway is not authorized to participate in a
Per-Peer Global Revocation. The mobile access gateway SHOULD NOT
retry sending a Binding Revocation Indication with the Global (G)
bit is set to the same local mobility agent. The mobile access
gateway should raise an alarm or log an event to indicate this
rejection.
11. Mobile Node Operation
11.1. Receiving Binding Revocation Indication
Upon receiving a packet carrying a Binding Revocation Indication, the
mobile node MUST validate the packet according to Section 7.2 and the
following tests:
o The mobile node MUST verify that the IP address in the type 2
routing header is its Home Address and that its Binding Update
List contains an entry for that Home Address. If one of the
tests, fails the mobile node SHOULD silently discard the received
BRI message.
o If the Acknowledgement (A) bit is set in the Binding Revocation
Indication and its Binding Update List contains an entry for the
IP address in the type 2 routing header, the mobile node MUST send
a Binding Revocation Acknowledgement. However, in all other cases
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when the (A) bit is set in the BRI, the mobile node SHOULD send a
Binding Revocation Acknowledgement. In all cases, the mobile node
MUST follow Section 11.2 and send a BRA using the appropriate
status code.
o If the IPv4 HoA Binding Only (V) bit is set in the received BRI
message, the MN MUST verify that there is an IPv4 HoA option in
the received BRI and the IPv4 address included in the IPv4 Home
Address option is the same as its IPv4 HoA that is assigned to the
mobile node. If this verification is successful, the MN MUST
consider this BRI as an indication to release the mobile node IPv4
HoA binding to its current Care-of Address ONLY. Consequently,
the MN MUST continue to maintain its IPv6 HoA binding to the
current CoA as part of the mobile node binding in the BUL entry
and release all resources associated with the MN IPv4 HoA binding.
In this case, the MN MUST send a BRA message with the status field
is set to success. On the other hand, if the IPv4 HoA option was
NOT included in the received BRI with the (V) bit set, the MN
SHOULD send a BRA message with the status field set to "IPv4 HoA
Option Required". Additionally, if the verification received IPv4
HoA in the IPv4 HoA option is NOT the one assigned to the MN, the
MN SHOULD send a BRA with the status field is set to "IPv4 HoA
Binding Does NOT Exist".
o The mobile node MUST verify that the (P) bit in the Binding
Revocation Indication is NOT set. If the (P) bit is set, the
mobile node MUST silently discard the Binding Revocation
Indication message.
o If the mobile node has registered multiple care-of addresses with
its home agent, the mobile node MUST verify which binding is being
revoked by examining the content of the BRI message. If the
mobile node received a Binding Revocation Indication with a single
or more than one Binding ID options and its home address is
included in the type 2 routing header, the mobile node MUST
consider all of the care-of address(es) binding(s), identified in
the Binding ID options, with this home address are being revoked.
o If the mobile node has multi Care-of Addresses bindings with its
home agent and received a Binding Revocation Indication, without
any Binding ID option included and its home address was included
in the type 2 routing header, the mobile node MUST consider all of
its registered care-of addresses bindings with this home address
are being revoked.
The Revocation Trigger field value in the received Binding Revocation
Indication could be used by the mobile node to define what action the
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mobile node could do to be able to register again and receive its IP
mobility service, e.g. contacting its home operator.
11.2. Sending Binding Revocation Acknowledgement
When the mobile node receives a Binding Revocation Indication from
its home agent, the mobile node processes the received BRI as in
Section 11.1. If the mobile node is required to send a BRA message
in response to the received BRI, the mobile node sends a packet to
its home agent containing a Binding Revocation Acknowledgement
according to the procedure in Section 7.1 and the following:
o The mobile node MUST set the status field to an appropriate value.
The mobile node sets the status field to success to reflect that
it has received the Binding Revocation Indication and acknowledge
that its IP connectivity with its home agent has been revoked.
o The destination IP address of the IPv6 packet of the Binding
Revocation Acknowledgement is set to the source IP address of the
received IPv6 packet of the Binding Revocation Indication. The
Mobile Node MUST include its home address in the Home Address
Destination Option.
12. Protocol Configuration Variables
Any mobility entity which is allowed to invoke the binding revocation
procedure by sending a Binding Revocation Indication message SHOULD
allow the following variables to be configured.
BRI Maximum Number of Retries (BRIMaxRetriesNumber)
This variable specifies the maximum Number of times a mobility
entity can retransmit a Binding Revocation Indication message
before receiving a Binding Revocation Acknowledgement message.
The default value for this parameter is 1.
Minimum Delay Between BRI messages (MINDelayBRIs)
This variable specifies the delay time in seconds before the
revoking mobility entity retransmits a BRI message. The default
is 1 second but not less than 0.5 seconds.
13. IANA Considerations
This document defines two new messages BRI and BRA, as described in
Section 6.1 and Section 6.2 by using Binding Revocation types of 1
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and 2 of the Binding Revocation Message which is defined in in
Section 6 and uses a MH type <IANA-TBD>. The new Mobility Header
type value needs to be assigned from the same numbering space as
allocated for the other Mobility Header types.
14. Security Considerations
The protocol described here uses the same security association
between the MN and the HA or the MAG and the LMA that has been used
to exchange the corresponding MIPv6 or Proxy MIPv6 BU and BA when the
session was established. If IPsec is used, The SPD of this IPsec SA
MUST allow the MH type for the Binding Revocation Message defined in
this document.
However, in the case when the MAG sends a BRI message with the Global
(G) bit is set, the LMA MUST verify that the MAG is authorized to use
Per-Peer Global Revocation.
15. Acknowledgements
The authors would like to thank Ryuji Wakikawa, Bruno Mongazon-
Cazavet, Domagoj Premec, Arnaud Ebalard, and Patrick Stupar for their
review and comments of this draft and all colleagues who have
supported the advancement of this draft effort.
16. References
16.1. Normative References
[ID-DSMIP6]
Soliman, H., "Mobile IPv6 Support for Dual Stack Hosts and
Routers", draft-ietf-mext-nemo-v4traversal-07 (work in
progress), December 2008.
[ID-MCoA] Wakikawa, R., Devarapalli, V., Ernst, T., and K. Nagami,
"Multiple Care-of Addresses Registration",
draft-ietf-monami6-multiplecoa-11 (work in progress),
January 2009.
[ID-PMIP6-IPv4]
Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", draft-ietf-netlmm-pmip6-ipv4-support-09
(work in progress), January 2009.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
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Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
in IPv6", RFC 3775, June 2004.
[RFC4283] Patel, A., Leung, K., Khalil, M., Akhtar, H., and K.
Chowdhury, "Mobile Node Identifier Option for Mobile IPv6
(MIPv6)", RFC 4283, November 2005.
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
16.2. Informative References
[RFC3344] Perkins, C., "IP Mobility Support for IPv4", RFC 3344,
August 2002.
[RFC3543] Glass, S. and M. Chandra, "Registration Revocation in
Mobile IPv4", RFC 3543, August 2003.
Authors' Addresses
Ahmad Muhanna
Nortel
2221 Lakeside Blvd.
Richardson, TX 75082
USA
Email: amuhanna@nortel.com
Mohamed Khalil
Nortel
2221 Lakeside Blvd.
Richardson, TX 75082
USA
Email: mkhalil@nortel.com
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Sri Gundavelli
Cisco Systems
170 West Tasman Drive
San Jose, CA 95134
USA
Email: sgundave@cisco.com
Kuntal Chowdhury
Starent Networks
30 International Place
Tewksbury, MA 01876
USA
Email: kchowdhury@starentnetworks.com
Parviz Yegani
Juniper Networks
1194 North Mathilda Avenue
Sunnyvale, CA 94089
USA
Email: pyegani@juniper.net
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