Netext Working Group F. Abinader, Ed. Internet-Draft Instituto Nokia de Tecnologia Intended status: Standards Track S. Gundavelli, Ed. Expires: January 3, 2012 K. Leung Cisco S. Krishnan Ericsson D. Premec Unaffiliated July 2, 2011 Bulk Re-registration Support for Proxy Mobile IPv6 draft-ietf-netext-bulk-re-registration-04 Abstract For extending the lifetime of a mobility session, the Proxy Mobile IPv6 specification requires the mobile access gateway to send a Proxy Binding Update message to the local mobility agent on a per-session basis. In the absence of signaling semantics for performing operations with group specific scope, it results in significant amount of signaling traffic on a periodic basis between a given mobile access gateway and a local mobility anchor. This document defines an optimization to the re-registration and revocation operations in Proxy Mobile IPv6 for performing operations with group specific scope by allowing the use of a group identifier. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on January 3, 2012. Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the Abinader, et al. Expires January 3, 2012 [Page 1] Internet-Draft Bulk Re-registration July 2011 document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions & Terminology . . . . . . . . . . . . . . . . . . 4 2.1. Conventions . . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 3. Bulk Registration Overview . . . . . . . . . . . . . . . . . . 4 3.1. Motivation for bulk re-registration . . . . . . . . . . . 4 3.2. Bulk re-registration operation . . . . . . . . . . . . . . 6 3.2.1. BULK_ADD_MN operation . . . . . . . . . . . . . . . . 7 3.2.2. BULK_REMOVE_MN operation . . . . . . . . . . . . . . . 7 3.2.3. BULK_REREG_SET operation . . . . . . . . . . . . . . . 8 3.2.4. BULK_TERMINATE_SET operation . . . . . . . . . . . . . 9 4. Message formats . . . . . . . . . . . . . . . . . . . . . . . 10 4.1. Extensions to Proxy Binding Update Message . . . . . . . . 10 4.2. Extensions to Proxy Binding Acknowledgment Message . . . . 11 4.3. Mobile Node Group Identifier Option . . . . . . . . . . . 11 4.4. Status Codes . . . . . . . . . . . . . . . . . . . . . . . 12 5. Protocol Considerations . . . . . . . . . . . . . . . . . . . 12 5.1. MAG Considerations . . . . . . . . . . . . . . . . . . . . 13 5.1.1. Requesting a Bulk Re-Registration Group Identifier . . 13 5.1.2. Sending a Bulk Re-registration Operation Request . . . 14 5.2. LMA Considerations . . . . . . . . . . . . . . . . . . . . 14 5.2.1. Assigning a Bulk Re-Registration Group Identifier . . 15 5.2.2. Handling a Bulk Re-registration Operation Request . . 16 6. Protocol Configuration Variables . . . . . . . . . . . . . . . 18 6.1. Local Mobility Anchor - Configuration Variables . . . . . 18 6.2. Mobile Access Gateway - Configuration Variables . . . . . 19 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 8. Security Considerations . . . . . . . . . . . . . . . . . . . 20 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 20 10. Normative References . . . . . . . . . . . . . . . . . . . . . 20 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 21 Abinader, et al. Expires January 3, 2012 [Page 2] Internet-Draft Bulk Re-registration July 2011 1. Introduction The Proxy Mobile IPv6 base specification [RFC5213] requires the Mobile Node Identifier (MN-ID) option to be present in the mobility signaling messages, such as in the Proxy Binding Update and Proxy Binding Acknowledgement messages. It essentially limits the operational scope of the signaling messages to a single mobile node. These signaling messages lack the capability to identify a set of mobile nodes which have a common characteristic and perform operations on the entire group. There is a need to have semantics for identifying a set of mobile nodes, so protocol operations can be performed on the entire group. The use of a group identifier in protocol operations can extend the scope of the operation to a larger set. A group identifier associated with a set of mobile nodes enables the ability to perform protocol operation on this set of mobile nodes via a single transaction. The group identifier also provides a more optimal mechanism for protocol operation which would otherwise require multiple atomic transactions on a per mobile node basis. Following are some of the use-cases where the group identifier can be used. o In a blade architecture system running the local mobility anchor service, all the mobile node sessions anchored on a given card can belong to a single group. When a failure occurs on a specific card, the local mobility anchor can initiate the revocation signaling to the mobile access gateway by sending a single revocation request carrying the group identifier. o For periodic re-registrations, the mobile access gateway have the option to send a single re-registration message for all the mobile nodes that belong to a group by having the mobile access gateway send a Proxy Binding Update to the local mobility anchor with the associated group identifier. o The mobile access gateway or the local mobility anchor can choose to revoke the registration of all mobile nodes associated with a specific group. In such cases the mobile access gateway or the local mobility anchor can perform the binding revocation signaling using the group identifier associated with a specific set of mobile nodes. The document defines a new mobility option, Mobile Node Group Identifier option, that can be used by a local mobility anchor and a mobile access gateway in the signaling messages for performing protocol operations with group specific scope. It also defines the applicability of the group identifier in operations such as binding re-registration and binding revocations [RFC5846] . Abinader, et al. Expires January 3, 2012 [Page 3] Internet-Draft Bulk Re-registration July 2011 2. Conventions & Terminology 2.1. Conventions 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 RFC 2119 [RFC2119]. 2.2. Terminology All the mobility related terms used in this document are to be interpreted as defined in the base Proxy Mobile IPv6 specifications [RFC5213] and [RFC5844]. Additionally, this document uses the following abbreviations: Group Identifier An opaque identifier that identifies a set of mobile nodes mobility sessions, that are part of a common logical group. This identifier is generated by the local mobility anchor and will be unique to each group. The specifics on how a given local mobility anchor groups different mobility sessions is out side the scope of this document. Bulk Registration A binding update operation that has group specific scope. A binding operation is typically associated with a specific mobility session. However, a Bulk Registration operation is associated with multiple mobility sessions. Bulk Registration Set It is a set of mobile node's mobility sessions that are part of the same logical group and thereby sharing a common group identifier. 3. Bulk Registration Overview 3.1. Motivation for bulk re-registration In a Proxy Mobile IPv6 domain a local mobility anchor serves multiple mobile access gateways and the capacity of that node with respect to the number of mobility sessions it can host is quite high. It is typically in the order of few millions of sessions. As the number of mobility sessions that the local mobility anchor hosts goes up, so will be the amount of signaling traffic related to periodic session Abinader, et al. Expires January 3, 2012 [Page 4] Internet-Draft Bulk Re-registration July 2011 refresh or sesson revocation traffic. The following simple formula gives an estimate of the average number of re-registration transactions per second as a function of the number of registered mobility sessions and the binding lifetime Transactions/sec = (Number of hosted mobility sessions) / (binding lifetime * 4) For a scenario of 500,000 MNs and the binding lifetime of half an hour this gives: 500,000 MNs / 1,800 sec = 277 transactions/sec Based on the above formula and example scenario it is apparent that the default PMIPv6 re-registration process where the mobile access gateway sends a unique binding refresh message for each mobility session is inefficient or suboptimal. These re-registration messages consume significant amount of network resources, both in terms of processing power and in terms of network bandwidth and both the ends. This document proposes an optimization of the Proxy Mobile IPv6 re- registration process by which the signaling load for re-registration can be reduced to a single transaction per mobile access gateway (the best case scenario), irrespective of the number of attached mobile nodes. According to this proposal, a mobile access gateway requests the local mobility anchor to add a MN into a bulk re-registration set by setting the bulk registration flag (B) in the first PBU message sent to the local mobility anchor, relative to the initial attachment of the MN to the mobile access gateway. The PBAck message sent in response contains the Mobile Node Group Identifier mobility option, defined on Section 4.3. In the context of bulk re-registrations the Mobile Node Group Identifier is an opaque identifier that is allocated by the local mobility anchor which uniquely identifies the bulk registration set to which an MN is added. A mobile access gateway requests a bulk re-registration for a set of MNs by sending a single PBU message which includes a Mobile Node Group Identifier option, and the local mobility anchor then extends the binding lifetime of all the MNs which belong to the specific group (identified by the Mobile Node Group Identifier option). By using this method, the mobile access gateway and local mobility anchor MAY accomplish the re-registration of MNs attached to a mobile access gateway in a single transaction. The number of re- registration transactions at the local mobility anchor becomes independent of the number of attached MNs; instead it is dependent only on the number of Group-ID sets at a mobile access gateway (i.e. bulk registration sets). In addition to minimizing the signaling overhead associated with the lifetime extension of the mobility bindings, the mobile access Abinader, et al. Expires January 3, 2012 [Page 5] Internet-Draft Bulk Re-registration July 2011 gateway and local mobility anchor can use a single timer per bulk registration set to monitor the binding lifetime of all the mobility sessions instead of an individual timer per mobility session 3.2. Bulk re-registration operation The bulk re-registration mechanism allows the mobile access gateway and the local mobility anchor to extend the binding lifetime for a number of MNs with a single transaction. The mobile access gateway and local mobility anchor maintain a set of MNs that can be re- registered in bulk mode. Such a set is called a bulk registration set, and is a subset of the MNs attached to a mobile access gateway. There can be multiple bulk registration sets for a given mobile access gateway-local mobility anchor pair; however, there can be only one mobile access gateway and one local mobility anchor associated with a given bulk registration set at any instance in time. There are two basic operations related to bulk registration sets which MAY be requested by the mobile access gateway for any given MN, namely BULK_ADD_MN or the addition of a MN to some bulk registration set (to be determined by the local mobility anchor) as specified on Section 3.2.1, and BULK_REMOVE_MN or the the removal of a MN from some bulk re-registration set, as specified in Section 3.2.2. In the case of the removal of a single MN from a bulk registration set (BULK_REMOVE_MN), the local mobility anchor MAY also take a unilateral decision to remove the MN, as specified on Section 3.2.2. In addition to these basic bulk registration set operations related to the scope of a single MN, the mobile access gateway MAY also request two additional bulk registration set operations which are related to the scope of all MNs contained on a given bulk registration set. The first of such operations is the BULK_REREG_SET operation (see Section 3.2.3), which allows the mobile access gateway to request the local mobility anchor to perform a collective re- registration all MNs within a given bulk registration set with a single atomic operation. The second of such operations is the BULK_TERMINATE_SET operation (see Section 3.2.4), which allows the mobile access gateway to request the local mobility anchor to remove all MNs previously contained in a given bulk registration set, meaning that all MNs previously in that bulk registration set MUST be individually registered again by the mobile access gateway on the local mobility anchor. Regarding this second operation (BULK_TERMINATE_SET), not only the mobile access gateway MAY make the request but also the local mobility anchor MAY unilaterally decide (for any given reason not covered by this document) that the mobility binding of all MNs previously contained on a given bulk registration set MUST be terminated, in which case the local mobility anchor uses the proper mechanism described in Section 3.2.4. Abinader, et al. Expires January 3, 2012 [Page 6] Internet-Draft Bulk Re-registration July 2011 The following sub-sections expand on the following operations: o BULK_ADD_MN o BULK_REMOVE_MN o BULK_REREG_SET o BULK_TERMINATE_SET 3.2.1. BULK_ADD_MN operation Initially the bulk registration set is empty. mobile access gateway requests to add individual MNs to the bulk registration set (while at the same time refreshing the MN binding itself) by sending a regular PBU message that (a) identifies an individual MN with its MN-ID and (b) sets the bulk re-registration flag in the message to 1. Based on the received bulk re-registration flag on the PBU message, the local mobility anchor takes the decision whether to add the MN to a bulk registration set or not. If the local mobility anchor decides for including the MN on a bulk registration set, it responds to the mobile access gateway with a PBAck message where (a) the bulk registration flag (B) set to 1 and (b) the bulk registration set to which the MN was added is represented by the Mobile Node Group ID option. If, instead, the local mobility anchor decides for reject the addition of the MN on a bulk registration set, the local mobility anchor processes the PBU message as if the bulk registration flag was not set, and responds with PBAck message where the bulk re- registration flag is set to 0. There MAY be different aspects involved in the local mobility anchor decision process whether to include or not a MN on a bulk registration set upon a request by the mobile access gateway via a PBU message with the the bulk registration flag (B) in the message set to 1. However, they MAY be implementation or domain specific, and therefore are outside the scope of this specification. 3.2.2. BULK_REMOVE_MN operation A mobile access gateway MAY remove a single MN from the bulk registration set in which it is currently included by sending a regular PBU message to the local mobility anchor identifying the MN to be removed (i.e. MN-ID) and with the bulk re-registration flag set to 0. This PBU message not only informs the local mobility anchor to remove the MN from its current bulk registration set, but also requests to refresh the binding of that MN as well, just as a regular PBU message would do. The local mobility anchor then responds with a regular PBAck message where the bulk registration Abinader, et al. Expires January 3, 2012 [Page 7] Internet-Draft Bulk Re-registration July 2011 flag set to 0 and the MN-ID that identifies that MN, therefore indicating to the mobile access gateway that the binding of such MN was refreshed. The local mobility anchor itself MAY also decide (for some implementation or domain specific reason not covered on this specification) to remove a single MN from its current bulk registration set, in which case it sends a non-solicited regular PBAck message to the mobile access gateway, with the the bulk registration flag set to 0 and with the MN identification field (i.e. MN-ID). This message not only informs that a given MN previously contained in a bulk re-registration set was removed, but also that the binding of such MN was also refreshed. If the lifetime value in the non-solicited PBAck message is set to a value different than 0, this MUST indicate to the mobile access gateway that the MN is no longer on a bulk registration set but the binding of the MN in the local mobility anchor is indeed refreshed and valid, and therefore this MN refreshing timer MUST be controlled separately in a proper way, just as a regular MN as per the [RFC5213]. If however the the lifetime value indicated in the non-solicited PBAck message is set to 0, it not only indicates that the MN was removed from the bulk registration set, but also that the binding of that MN on the local mobility anchor itself has expired, and therefore is no longer valid. 3.2.3. BULK_REREG_SET operation Once there is a non-empty bulk registration set registered at the local mobility anchor (with one or more MNs), the mobile access gateway can request to extend the binding lifetime for all MNs belonging to such bulk registration set by sending a PBU message with the bulk registration (B) flag set and by including the Mobile Node Group ID identifying the bulk registration set itself, which value was previously received from the local mobility anchor. Such PBU message lacks any options that identify an individual MN. In particular, the mobile access gateway omits both the MN-ID (Mobile Node Identifier) and the HNP (Home Network Prefix) options. mobile access gateway MAY also include multiple instances of the Mobile Node Group Identifier option in a single PBU message only if the intent is to request lifetime refreshment for several bulk registration sets at the same time. Even further, the mobile access gateway MAY even request to re-register all bulk re-registration sets previously established with the local mobility anchor by sending a single PBU message where there is a single Mobile Node Group Identifier option with the value of all bits set to 1 (see Section 4.3 for more information). However, PBU messages that try to extend binding time to some bulk registration sets while at the same time terminating bindings with other bulk registration sets (e.g. by Abinader, et al. Expires January 3, 2012 [Page 8] Internet-Draft Bulk Re-registration July 2011 setting zero lifetime) in the same PBU message are not possible, as this PBU message would be ambiguous in determining which bulk registration sets would be refreshed and which bulk registration sets would be terminated. As a consequence, if for some reason those two classes of operations need to be performed concurrently, they MUST be done with the use of separate PBU messages. Upon the receive of the PBU message with the bulk registration (B) bit set and by including the Mobile Node Group ID instance(s) identifying the bulk registration set(s) to re-register (i.e. refresh the binding of each MN belonging to each bulk registration set informed), the local mobility anchor extends the mobility binding of all MNs that are members of the indicated bulk registration set(s) and responds with the PBAck message echoing the received Mobile Node Group Identifier mobility options, in special with the bulk registration (B) flag set and including the Mobile Node Group ID instance(s) identifying the bulk registration set(s) re-registered. 3.2.4. BULK_TERMINATE_SET operation A mobile access gateway MAY request to terminate any given bulk registration set at any moment with a single atomic operation, which implicates (a) in the expiration of the mobility bindings of all the MNs belonging to that bulk registration set on the local mobility anchor at the same time and (b) on the termination of the bulk registration set itself on both the mobile access gateway and the local mobility anchor. For that, the mobile access gateway sends a PBU message with the bulk registration flag (B) set to 1, sets the lifetime value to zero and informs the bulk registration set to the local mobility anchor by including the Group I-D option in the message. Here, the mobile access gateway MAY also perform the termination of more than one bulk registration sets with a single atomic operation, in which case the PBU message contains the multiple mobile node Group I-D options representing these multiple bulk registration sets. Finally, the mobile access gateway MAY also request to terminate all bulk registration sets, in which case it SHOULD send the Group I-D option with the value of all bits set to 1 (see Section 4.3 for more information). Upon receive of such PBU message indicating a bulk registration termination request, the local mobility anchor expires the mobility bindings of all the MNs belonging to all the bulk registration sets specified in the PBU message and extinguish the representations of the bulk registration sets themselves. Then, the local mobility anchor sends back a PBAck message to the mobile access gateway, reproducing all the mobility options informed on the original PBU message, including the bulk registration flag (B) set to 1, the lifetime value set to zero and the Group I-Ds originally mentioned. Abinader, et al. Expires January 3, 2012 [Page 9] Internet-Draft Bulk Re-registration July 2011 4. Message formats This section identifies the extensions to Proxy Mobile IPv6 binding update messages that are required for supporting this specification. 4.1. Extensions to Proxy Binding Update 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence # | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |A|H|L|K|M|R|P|F|T|B| Reserved | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Mobility options . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 A new flag, Bulk Registration (B) flag is defined in the Proxy Binding Update message specified in [RFC5213]. The bit-value of Bulk Registration (B) flag in the flags field of the message will be TBD(0x0040 - subject to IANA approval). Bulk Registration Flag (B): If the bulk registration flag (B) is set to a value of (1), it serves as a request to the local mobility anchor to include the mobile node's session to the bulk registration set. If the bulk registration flag (B) is set to a value of (0), the local mobility anchor MUST exclude the mobile node's session from the bulk registration set and thus any any operations with bulk scope will not be applied to the mobile node's session. All other fields in the Proxy Binding Update message and the mobility options that can be carried in the message and any related considerations confirm to the base Proxy Mobile IPv6 specifications [RFC5213] and [RFC5844]. Abinader, et al. Expires January 3, 2012 [Page 10] Internet-Draft Bulk Re-registration July 2011 4.2. Extensions to Proxy Binding Acknowledgment 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Status |K|R|P|T|B| Res.| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence # | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Mobility options . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: Proxy Binding Acknowledgment Message A new flag, Bulk Registration (B) flag is defined in the Proxy Binding Acknowledgment message specified in [RFC5213]. The bit-value of Bulk Registration (B) flag in the flags field of the message is TBD (0x01 - subject to IANA approval). Bulk Registration Flag (B): If the bulk registration flag (B) is set to a value of (1), it serves as an indication to the mobile access gateway that the mobile node's session was successfully added to the bulk registration set. The value of flag MUST NOT be set to the value of (1), if the value of the (B) flag in the Proxy Binding Update message that it received from the mobile access gateway was not set to a value of (1). All other fields in the Proxy Binding Acknowledgment message and the mobility options that can be carried in the message and any related considerations confirm to the base Proxy Mobile IPv6 specifications, [RFC5213] and [RFC5844]. 4.3. Mobile Node Group Identifier Option A new option, Mobile Node Group Identifier option is defined for using it in Proxy Mobile IPv6 signaling messages exchanged between a local mobility anchor and a mobile access gateway. This option is used for carrying the mobile node's group identifier. There can be multiple instances of this option in a given signaling message, however, each of the instance SHOULD have a different sub-type. The alignment requirement for this option is 4n. The type value for this option is TBD (46 - subject to IANA approval) Abinader, et al. Expires January 3, 2012 [Page 11] Internet-Draft Bulk Re-registration July 2011 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 | Sub-type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mobile Node Group Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: Mobile Node Group Identifier Option Type Length 8-bit unsigned integer indicating the length in octets of the option, excluding the type and length fields. The value for this field MUST be set to a value of (6). Sub-type Identifies the specific group type. This number space will be managed by the IANA. The sub-type value of (1) is reserved for Bulk Re-Registration and Revocation group and the sub-type value of (255) is reserved for the group, all nodes attached to the mobile access gateway that have mobility sessions on a given local mobility anchor. Mobile Node Group Identifier A 32-bit field containing the mobile node's group identifier. The group identifier reflects the group affiliation that is local to a specific LMA-MAG pair. 4.4. Status Codes This document defines the following new Status codes values for use in the Proxy Binding Acknowledgement message. These values are to be allocated from the same numbering space, as defined in Section 6.1.8 of [RFC3775]. INVALID_MOBILE_NODE_GROUP_IDENTIFIER: IANA Invalid group identifier value in the request 5. Protocol Considerations Abinader, et al. Expires January 3, 2012 [Page 12] Internet-Draft Bulk Re-registration July 2011 5.1. MAG Considerations The following considerations MUST be applied by the mobile access gateway. The conceptual Binding Update List entry data structure maintained by the mobile access gateway, described in Section 6.1 of [RFC5213], MUST be extended to store the mobile node's group identifier. The mobile access gateway SHOULD maintain distinct bulk registration sets for each local mobility anchor and there could be several such sets on a per mobile access gateway basis. 5.1.1. Requesting a Bulk Re-Registration Group Identifier The following sections identify the considerations for requesting the local mobility anchor to assigned a Bulk Re-registration and Revocation group identifier for the mobility session, so the mobile access gateway can use the group identifier when requesting re- registration or revocation operation with group specific scope. o When sending a Proxy Binding Update message to the local mobility anchor, the mobile access gateway MAY choose to request the local mobility anchor to enable bulk re-registration and revocation support for the mobility session associated with that Proxy Binding Update request. When making such request, the bulk registration flag (B) in the request MUST be set to a value of (1). The decision to request the bulk re-registration mode for a mobile node is a matter of local policy at the mobile access gateway and is controlled by the configuration variable, RequestBulkRegAndRevSupportForMobilitySession. o Upon receiving the Proxy Binding Acknowledgment message with status code value set to (0) (Proxy Binding Update accepted), the bulk registration flag (B) in the reply is set to a value of (1) and there is a mobile node group identifier option present, the message serves as a hint that the local mobility anchor has enabled bulk registration support for the mobility session and that the mobile access gateway MAY use the group identifier when requesting re-registration or revocation operation with group specific scope. The group identifier value in Binding Update List entry MUST also be updated to include the assigned group identifier. o At any point of time, the mobile access gateway chooses to request the local mobility anchor to disable bulk re-registration and revocation support for a mobility session, it MUST send a Proxy Binding Update message with the bulk registration (B) flag set to a value of (0). This message is sent as a normal re-registration Abinader, et al. Expires January 3, 2012 [Page 13] Internet-Draft Bulk Re-registration July 2011 request for lifetime extension. Considerations from section 6.9.1 [RFC5213] MUST be applied. 5.1.2. Sending a Bulk Re-registration Operation Request The following section identifies the considerations for mobile access gateway for including a mobile node's mobility session to bulk re- registration group. o For extending the lifetime of all mobility sessions that share the same group identifier, the mobile access gateway MAY choose to send a Bulk re-registration request. For making such request, it can send a Proxy Binding Update message to the local mobility anchor including the Mobile Node Group Identifier option. The identifier value in the option MUST be set to the identifier of the group for which bulk re-registration operation is being requested. The message MUST NOT include Mobile Node Identifier option [RFC5213], Home Network Prefix option [RFC5213], or the IPv4 Home Address Request option [RFC5844]. All the Considerations from section 5.3.3 [RFC5213] MUST be followed when sending this request, with exception related to the use of Mobile Node Group Identifier option in place of the individual session identifiers. o When requesting binding revocation for all the sessions that share the same group identifier, the mobile access gateway MAY choose to send a Bulk revocation request. For making such request, it can send a Binding Revocation Indication message to the local mobility anchor including the Mobile Node Group Identifier option. The identifier value in the option MUST be set to the identifier of the group for which bulk re-registration operation is being requested. The message MUST NOT include Mobile Node Identifier option [RFC5213], Home Network Prefix option [RFC5213], or the IPv4 Home Address Request option [RFC5844]. All the Considerations from section 9.2 [RFC5846] MUST be followed when sending this request, with exception related to the use of Mobile Node Group Identifier option in place of the individual session identifiers. 5.2. LMA Considerations For supporting this specification, the following considerations MUST be applied by the local mobility anchor when processing Proxy Mobile IPv6 signaling messages. The conceptual Binding Cache entry data structure maintained by the local mobility anchor, described in Section 5.1 of [RFC5213] must be extended to store the mobile node's Bulk Re-Registration and Abinader, et al. Expires January 3, 2012 [Page 14] Internet-Draft Bulk Re-registration July 2011 Revocation group identifier. 5.2.1. Assigning a Bulk Re-Registration Group Identifier This section identifies the considerations for local mobility anchor for assigning a Bulk Re-registration and Revocation group identifier to a mobility session. o The local mobility anchor will process a received Proxy Binding Update message as specified in [RFC5213]. However, if the bulk registration flag (B) in the received Proxy Binding Update message is set to a value of (1), or if it includes a Mobile Node Group Identifier option, the local mobility anchor applies the following additional considerations. o If the bulk registration flag (B) in the received Proxy Binding Update message is set to a value of (1) and if the Mobile Node Group Identifier option is not present in the request, the message serves as a request to the local mobility anchor to include the mobile node's session to the bulk re-registration and revocation set. Upon successful processing and acceptance of the Proxy Binding Update, the local mobility anchor MAY choose to enable bulk re-registration and revocation mode support for this mobility session by including the mobility session to the bulk re- registration and revocation set. The decision whether to enable bulk re-registration and revocation mode for that mobility session is a matter of local policy and is controlled by the configuration variable, AcceptBulkRegAndRevSupportForMobilitySession. o For enabling the bulk re-registration and revocation mode support for the mobility session, the local mobility anchor MAY choose to associate the mobility session with a specific group of mobility sessions. The specific details on how the local mobility anchor associates the given mobile node's mobility session to a specific bulk re-registration and revocation set is outside the scope of this document. The group identifier field in the Binding Cache entry is updated with the identifier of the group to which the mobility session is associated. o If the bulk re-registration and revocation mode support is enabled for the mobile node's mobility session, the local mobility anchor MUST send the group identifier of the bulk re-registration and revocation set as part of the Mobile Node Group Identifier option in the Proxy Binding Acknowledgment message that it sends to the mobile access gateway. The bulk registration flag (B) in the Proxy Binding Acknowledgment message MUST be set to value of (1). Abinader, et al. Expires January 3, 2012 [Page 15] Internet-Draft Bulk Re-registration July 2011 o If the bulk re-registration and revocation mode support is not enabled for the mobile node's mobility session, the local mobility anchor MUST NOT include the Mobile Node Group Identifier option with a sub-type value of (1) in the Proxy Binding Acknowledgment reply that it sends to the mobile access gateway. Furthermore, bulk registration flag (B) in the Proxy Binding Acknowledgment message MUST be set to value of (0). o If the received Proxy Binding Update message is not a bulk re- registration request, (i.e., bulk registration (B) flag is set to a value of (0) and the Mobile Node Group Identifier option is not present), but is a request for extending the lifetime of an existing mobility session which is already part of a bulk re- registration set, then the local mobility anchor MUST process the request as specified in [RFC5213]. However, the value of (0) bulk registration (B) flag in the message serves as a request for the local mobility anchor to remove the session from performing bulk re-registration and revocation operations. Upon accepting the request, the mobility session MUST be removed from the bulk re- registration and revocation set. The value of the group identifier in the Binding Cache entry must be set to the value of (0). o Any time the local mobility anchor detects that the mobile node has roamed and changed its point of attachment to a new mobile access gateway, it SHOULD also update the group identifier of the mobility session. As part of sending the Proxy Binding Acknowledgment to the new mobile access gateway, it MUST include the updated group identifier in the Mobile Node Group identifier option. However, if the if the received Proxy Binding Update from the new mobile access gateway did not have bulk registration (B) flag set to a value of (1), then it MUST NOT include the mobility session in any of bulk re-registration and revocation groups and MUST NOT include the Mobile Node Group identifier option with the sub-type value of (1). o Any time a mobile node's mobility session is de-registered by the mobile access gateway, or the session is revoked for administrative or any other reasons, the mobility session MUST also be removed from the bulk re-registration and revocation set. set. 5.2.2. Handling a Bulk Re-registration Operation Request The following are the considerations related to handling bulk re- registration request. Abinader, et al. Expires January 3, 2012 [Page 16] Internet-Draft Bulk Re-registration July 2011 o Any time the local mobility anchor receives a Proxy Binding Update message with a Mobile Node Group Identifier option present in the request and with sub-type value of (1) (bulk registration group), the local mobility anchor MUST consider the request as a Bulk Re- registration request, with the request scope for extending the lifetime of all the mobility sessions that share the same group identifier present in the Mobile Node Group Identifier option. However, if the received request also includes a Mobile Node Identifier option [RFC5213], Home Network Prefix option [RFC5213], or the IPv4 Home Address Request option [RFC5844] the local mobility anchor MUST consider this as an invalid message; it must reject the Proxy Binding Update message and send a Proxy Binding Acknowledgement message with the Status field set to INVALID_MOBILE_NODE_GROUP_IDENTIFIER (Invalid group identifier value in the request). o There can be multiple instances of the Mobile Node Group Identifier option with sub-type value of (1), present in the request. However, the group identifier value in each of these options MUST be different. Currently, this specification only support sub-type value of (1). If this requirement is not met, the local mobility anchor must reject the Proxy Binding Update message and send a Proxy Binding Acknowledgement message with the Status field set to INVALID_MOBILE_NODE_GROUP_IDENTIFIER (Invalid group identifier value in the request). The local mobility anchor MUST consider the message as a request for extending the lifetime of all the mobility sessions that are associated to each of group identifier from the Mobile Node Group Identifier option. o Upon accepting the Bulk Re-registration request, the local mobility anchor SHOULD extend the lifetime for all the mobility sessions that are part of bulk registration sets identified by the group identifier option(s) included in the message. Considerations from [RFC5213] MUST be applied for extending the lifetime of a mobile node's session. It MUST also send a Proxy Binding Acknowledgment message with the Status field value set to 0 (Proxy Binding Update accepted). The lifetime field in the message MUST be set to the allocated lifetime for all the mobility sessions. The message MUST also include the Mobile Node Group Identifier option, with the identifier value copied from the Mobile Node Group Identifier option present in the received Proxy Binding Update message. o If the local mobility anchor rejects the bulk re-registration request for any administrative reason, then it MUST NOT update the lifetime in the binding cache entries of any of the mobile nodes identified by the group identifier. The local mobility anchor SHOULD send a Proxy Binding Acknowledgment indicating the reason Abinader, et al. Expires January 3, 2012 [Page 17] Internet-Draft Bulk Re-registration July 2011 for the rejection in the status code. o Any time the local mobility anchor receives a Binding Revocation Indication Message [RFC5846], with a Mobile Node Group Identifier option present in the request and with sub-type value of (1) (bulk re-registration and revocation group), the local mobility anchor MUST consider the request as a Bulk Revocation request, with the request scope for revoking of all the mobility sessions that share the same group identifier present in the Mobile Node Group Identifier option. However, if the received request also includes a Mobile Node Identifier option [RFC5213], Home Network Prefix option [RFC5213], or the IPv4 Home Address Request option [RFC5844] the local mobility anchor MUST consider this as an invalid message; it must reject the Binding Revocation Indication message and send a Binding Revocation Acknowledgement message with the Status field set to a value of 128 (Binding Does NOT Exist). All the considerations from [RFC5846] apply when processing binding revocation request, expect making the scope of the operation apply to a set of mobility sessions identified by the group identifier present in the request. o Upon accepting the Binding Revocation Indication request and completing the operation, the local mobility anchor MUST send a Binding Revocation Acknowledgement message with the Status field set to a value of 0 (success). The message MUST include the Mobile Node Group Identifier option, with the identifier value copied from the Mobile Node Group Identifier option present in the received Binding Revocation Indication message. 6. Protocol Configuration Variables 6.1. Local Mobility Anchor - Configuration Variables The local mobility anchor MUST allow the following variables to be configured by the system management. The configured values for these protocol variables MUST survive server reboots and service restarts. AcceptBulkRegAndRevSupportForMobilitySession This flag indicates whether or not the local mobility anchor should accept the request from the mobile access gateway to enable Bulk Re-Registration and Revocation support for the mobility session. The default value for this flag is set to (1), indicating that it SHOULD accept the request from the mobile access gateway. If the value of the flag is set to (0), the local mobility anchor MUST deny the request. Abinader, et al. Expires January 3, 2012 [Page 18] Internet-Draft Bulk Re-registration July 2011 6.2. Mobile Access Gateway - Configuration Variables The mobile access gateway MUST allow the following variables to be configured by the system management. The configured values for these protocol variables MUST survive server reboots and service restarts. RequestBulkRegAndRevSupportForMobilitySession This flag indicates whether or not the mobile access gateway should request the local mobility anchor to enable Bulk Re- Registration and Revocation support for the mobility session. The default value for this flag is set to (1), indicating that the the mobile access gateway MUST set the bulk registration flag (B) in the Proxy Binding Update request. If the flag is set to a value of (0), the mobile access gateway MUST set the bulk registration flag (B) in the Proxy Binding Update request to a value of (1). 7. IANA Considerations This document requires the following five IANA actions. o Action-1: This specification defines a new flag (B) to the Proxy Binding Update message, specified in [RFC5213]. This flag is described in Section 4.1. The value of the flag (B) needs to be allocated from the Binding Update Flags registry. o Action-2: This specification defines a new flag (B) to the Proxy Binding Acknowledgment message, specified in [RFC5213]. This flag is described in Section 4.2. The value of the flag (B) needs to be allocated from the Binding Acknowledgment Flags registry. o Action-3: This specification defines a new Mobility Header option, the Mobile Node Group Identifier option. This option is described in Section 4.3. The Type value for this option needs to be assigned from the same numbering space as allocated for the other mobility options [RFC3775]. o Action-4: The Sub-type field of the Mobile Node Group Identifier option introduces a new number space. This number space needs to be managed by IANA, under the Registry, Mobile Node Group Identifier Type Registry. This specification reserves the sub- type value of (1) and (255). Approval of new sub-type values are to be made through IANA Expert Review. o Action-5: This document also defines new status values, used in Proxy Binding Acknowledgement message, as described in Section 4.4. These values are to be assigned from the same number Abinader, et al. Expires January 3, 2012 [Page 19] Internet-Draft Bulk Re-registration July 2011 space as allocated for other Status codes [RFC3775]. Each of these allocated values have to be greater than 128. INVALID_MOBILE_NODE_GROUP_IDENTIFIER o Invalid group identifier value in the request: IANA 8. Security Considerations The Mobile Node Group Identifier option defined in this specification is for use in Proxy Binding Update and Proxy Binding Acknowledgement messages. This option is carried like any other mobility header option as specified in [RFC3775] and does not require any other special security considerations. As per [RFC5213], the Mobile Node Identifier option, which carries the identification of the mobile node is always present in the Proxy Mobile IPv6 signaling messages. When these signaling messages are not privacy protected by IPsec or any other mechanism, it can result in compromising the privacy of the user to an attacker monitoring these messages. Similarly, when carrying the Mobile Node Group Identifier option in Proxy Mobile IPv6 signaling messages with no privacy protection turned on, the same vulnerability will be present. Specifically, the group affiliation of the user when exposed can result in compromising the privacy of the user or the location information. The Bulk binding update operations specified in this document, do not introduce any new security threat or vulnerability to the Proxy Mobile IPv6 protocol security. 9. Acknowledgements The authors would like to specially thank Jouni Korhonen and Basavaraj Patil for their reviews and inputs to the document. The authors would like to acknowledge all the prior discussions on this topic in netlmm mailing list. 10. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support Abinader, et al. Expires January 3, 2012 [Page 20] Internet-Draft Bulk Re-registration July 2011 in IPv6", RFC 3775, June 2004. [RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. [RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy Mobile IPv6", RFC 5844, May 2010. [RFC5846] Muhanna, A., Khalil, M., Gundavelli, S., Chowdhury, K., and P. Yegani, "Binding Revocation for IPv6 Mobility", RFC 5846, June 2010. Authors' Addresses Fuad Abinader (editor) Instituto Nokia de Tecnologia Av. Torquato Tapajos, 7200 - Km. 12 - Col Terra Nova Manaus, AM 69048-660 BRAZIL Email: fuad.junior@indt.org.br Sri Gundavelli (editor) Cisco 170 West Tasman Drive San Jose, CA 95134 USA Phone: Fax: Email: sgundave@cisco.com URI: Kent Leung Cisco 170 West Tasman Drive San Jose, CA 95134 USA Phone: Fax: Email: kleung@cisco.com URI: Abinader, et al. Expires January 3, 2012 [Page 21] Internet-Draft Bulk Re-registration July 2011 Suresh Krishnan Ericsson 8400 Decarie Blvd. Town of Mount Royal, QC Canada Phone: +1 514 345 7900 x42871 Fax: Email: suresh.krishnan@ericsson.com URI: Domagoj Premec Unaffiliated Email: domagoj.premec@gmail.com Abinader, et al. Expires January 3, 2012 [Page 22]