Internet Draft Tetsuya Arita <draft-arita-netext-pnemo-00.txt> Fumio Teraoka Keio univ. Expires April 2011 October 12, 2010 Proxy Network Mobility Protocol <draft-arita-netext-pnemo-00.txt> Status of this Memo Distribution of this memo is unlimited. 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), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on April, 2011. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the 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. Arita, et al Expires March 2011 [Page 1]
Internet Draft Proxy Network Mobility Protocol October 12, 2010 Abstract Proxy Mobile IPv6 (PMIPv6) provides the Internet connectivity to Mobile Node in a PMIPv6 domain. Current PMIPv6 specification supports only Host Mobility. In order to support a network mobility, this document defines Proxy Mobility Protocol that provides and maintains the connectivity for the Mobile Network Node (MNN) in the mobile network (nemo). This document discusses the deployment consideration of PNEMO and proposes the possible solution accordingly. Arita, et al Expires March 2011 [Page 2]
Internet Draft Proxy Network Mobility Protocol October 12, 2010 Table of Contents 1. Introduction ....................................................3 2. Conventions and Terminology .....................................4 3. Proxy Network Mobility Protocol .................................4 3.1 Protocol Overview ............................................4 3.2 Nested Network ...............................................7 4. Local Mobility Anchor Operation ................................10 5. Mobile Access Gateway Operation ................................11 6. Mobile Router Operation ........................................13 7. References .....................................................14 7.1. Normative References .......................................14 1. Introduction Network Mobility Basic Support (NEMO BS) [RFC-3963] was proposed to support network mobility. Similar to Mobile IPv6 (MIPv6) [RFC-3775], the Home Agent (HA) and the Mobile Router (MR) are important entities in NEMO BS. The HA maintains the prefix of the mobile network (nemo) and forwards packets to and from the nemo. The MR establishes a bi- directional tunnel to the HA. However, NEMO BS has several problems. If the nemo is nested, the header overhead increases because of multiple tunnels. If the wireless link between the MR and the access router (AR) is unstable after handover, the signaling messages such as Binding Update (BU) might be lost. Proxy Mobile IPv6 (PMIPv6) [RFC-5213] provides mobility to the Mobile Node (MN) in the PMIPv6 domain. To achieve mobility in the PMIPv6 domain, the Local Mobility Anchor (LMA) and the Mobile Access Gateway (MAG) are installed. The LMA serves as the HA in MIPv6. It manages the binding between the LMA and the MAG to which the MN is attached. The MAG sends the signaling messages to MN's LMA on behalf of the MN. It establishes a bi-directional tunnel to the LMA. In PMIPv6, the signaling messages are exchanged in the wired network. Even if the wireless link between the MN and the MAG is unstable after handover, the signaling messages between the MAG and the LMA are rarely lost. This document defines a protocol called PNEMO that provides network- based localized mobility to a mobile network. In PNEMO, the signaling messages are exchanged between the MAG and the LMA, i.e., the MR does not participate in the signaling procedure. PNEMO is an extension of PMIPv6. The MR sends and receives the packets for the Visited Mobile Node (VMN) and the Local Fixed Node (LFN). It also informs the state of the nemo to the LMA and the MAG. As the LMA and the MAG manage the location information of the VMN and the nested network, they can forward the packets to the VMN and the nested network in the nemo. Arita, et al Expires March 2011 [Page 3]
Internet Draft Proxy Network Mobility Protocol October 12, 2010 The MR has the NEMO State Table, which manages the location information of the VMN and the nested network in its lower subnet. 2. Conventions and Terminology 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 [RFC-2119]. 3. Proxy Network Mobility Protocol 3.1. Protocol Overview This document defines the specification of a network-based mobility management protocol for a mobile network (nemo), called Proxy Network Mobility Protocol (PNEMO). It is an extension of Proxy Mobile IPv6. The LMA and the MAG will keep track of nemo's movements, initiate the mobility signaling, and set up the required routing state. The entities in the NETLMM infrastructure are the LMA, the MAG and the MR. The LMA is responsible for maintaining the reachability state of the MR and the VMN. it allocates the prefixes for mobile nodes to configure their address. The MR is allocated the Home Network Prefix (HNP) and the Mobile Network Prefix (MNP). The VMN is allocated the HNP. The LMA is the topological anchor point for these prefixes. The MAG is the entity that performs the mobility management on behalf of the MR and the VMN. It emulates the Home Link of the MR and the VMN. It is responsible for detecting nemo's movements to and from the access link and for initiating binding registrations to the LMA of the MR's or the VMN's. The MAG itself manages its binding information of the nemo. When the MAG receives packets destined to the nodes in the nemo, it forwards the packets to the corresponding MR. A nemo consists of a MR, VMNs and LFNs. The MR is the default router of the nemo and the entity that manages the nested network. In the nested nemo, the MR informs the configuration change in the nemo to the MAG. The LFN in the nemo configures its address using the MNP advertised by the MR. Arita, et al Expires March 2011 [Page 4]
Internet Draft Proxy Network Mobility Protocol October 12, 2010 +-----+ | LMA | +-----+ |<--LMAA Tunnel-->// +-------//---+ ( // )<-- IPv6 Network ( // ) +----//------+ | |<-Proxy-CoA +-----+ ____MR-HNP | MAG | / +-----+-----{ MR } | | VMN-HNP-->| |<--LFN-MNP { VMN } { LFN } Figure 1. Architecture of PNEMO The architecture of PNEMO is shown in Figure 1. In this figure, a VMN and a nemo composed of a MR and a LFN are attached to a MAG. Figure 2 shows the signaling flow when a nemo enters a PMIPv6 domain. When the MR is attached to a PMIPv6 domain, the MAG detects MR's attachment and acquires MR's identifier. It determines whether the MR is authorized for the network-based mobility management service. After the MR is authorized for the network-based mobility service, the MAG sends the Proxy Binding Update (PBU) message to MR's LMA to register the current location of the MR. When the LMA accepts the PBU message, it creates the Binding Cache Entry for the MR and sets up its endpoint of the bi-directional tunnel to the MAG. Then the LMA sends the Proxy Binding Acknowledgement (PBA) message including the HNP and the MNP to the MAG that the MR attaches to. When the MAG receives the PBA message, it sets up its endpoint of the bi-directional tunnel to the LMA and also sets up the forwarding state for nemo's traffic. To emulate the Home Link of the MR, the MAG configures certain link local addresses. Then, it sends the Router Advertisement (RA) message to the MR. The MR configures its address using the HNP advertised by the MAG and it advertise the RA message including the MNP to the nemo. If there is a LFN in the nemo, the LFN configures its address using Arita, et al Expires March 2011 [Page 5]
Internet Draft Proxy Network Mobility Protocol October 12, 2010 the MNP. The LMA and the MAG have proper routing states for handling the traffic sent to and from the nemo using the address from its MNP. +-----+ +----+ +-----+ +-----+ | LFN | | MR | | MAG | | LMA | +-----+ +----+ +-----+ +-----+ | | | | | Attached | | | | | | | | Detect Attachment event | | | (Acquire MR-ID/ Profile) | | |-- Rtr Sol ----->| | | | |-- PBU ------------>| | | | Accept PBU | | | (Allocate HNP/MNP, | | | Setup BCE/Tunnel) | | |<------------ PBA --| | | Accept PBA | | | (Setup Tunnel and Routing) | | | | | | | |== Bi-Dir Tunnel ===| | |<----- Rtr Adv --| | | | (HNP,MNP) | | | IP Address | | | Configuration | | | | | | |<- Rtr Adv --| | | | (MNP) | | | IP Address | | | Configuration | | | | | | | Figure 2. Mobile Router Attachment - Signaling Call Flow Figure 3 shows the signaling flow for nemo's handoff. The MR moves from the previously attached MAG (p-MAG) to the newly attached MAG (n-MAG). When the MR changes its point of attachment to the Internet, the p-MAG can detect MR's detachment from the access link. The p-MAG sends a De-registration request message to MR's LMA and deletes the binding and routing state for the MR. On receiving the request message, the LMA accepts the request and deletes the binding for the MR if the LMA does not receive the PBU from the n-MAG within the timeout. When the MR is attached to the new link, the n-MAG detects MR's attachment. Then, the n-MAG sends the PBU message to MR's LMA to Arita, et al Expires March 2011 [Page 6]
Internet Draft Proxy Network Mobility Protocol October 12, 2010 update the binding state. After the signaling procedure, the n-MAG sends the RA message to advertise the HNP and the MNP to the MR. The MR does not detect the changes with respect to the layer-3 attachment of this interface. On receiving the RA message from the n-MAG, the MR sends the RA message with the MNP to the nemo. The LFN receives the RA message and configures its address if it does not have its address. In Figure 3, the RS message and the RA message are exchanged between the MR and the n-MAG. Because the MR has already set its address and the default router, the MR does not need the RA message. +-----+ +----+ +-----+ +-----+ | LFN | | MR | |p-MAG| | LMA | +-----+ +----+ +-----+ +-----+ | | |== Bi-Dir Tunnel ===| | Detached | | | | Detect Detachment event | | | | | | | | | | | | | | +-----+ | | | |n-MAG| | | | +-----+ | | Attached | | | | Detect Attachment event | | | | | | |--(Rtr Sol)----->| | | | |-- PBU ------------>| | | | | | | |<------------ PBA --| | |<-----(Rtr Adv)--| | |<- Rtr Adv --| (HNP,MNP) |== Bi-Dir Tunnel ===| | (MNP) | | | | | | | Figure 3. Mobile Network Handoff - Signaling Flow 3.2 Nested network Figure 4 shows an example of a nested nemo. Figure 5 shows the signaling flow when a nemo is nested. When another MR (MR2) or a VMN is attached to the MR (MR1) which is connected to the MAG, MR1 detects MR2's or VMN's attachment. Then MR1 sends the Nested Binding Update (NBU) message including MR2's or VMN's identifier to the MAG. Arita, et al Expires March 2011 [Page 7]
Internet Draft Proxy Network Mobility Protocol October 12, 2010 After the MAG receives the NBU message, it determines whether MR2 or the VMN are authorized for the network-based mobility management service. +-----+ | LMA | +-----+ | // // | +-----+ | MAG | +-----+ | +-----+ | MR1 | +-----+ _______|_______ | | +-----+ | | MR2 | {VMN} +-----+ | +-----+ | MR3 | +-----+ Figure 4. the nested Mobile Network of PNEMO Arita, et al Expires March 2011 [Page 8]
Internet Draft Proxy Network Mobility Protocol October 12, 2010 +-----+ +----+ +-----+ +-----+ | VMN | | MR1| | MAG | | LMA | +-----+ +----+ +-----+ +-----+ | | |== Bi-Dir Tunnel ===| Attach Event | | | | Detect Attach event | | | | | | |- Rtr Sol -->| | | | |-- NBU --------->| | | | |-- PBU ------------>| | | | Create BCE | | |<------------ PBA --| | |<--------- NBA --| | |<- Rtr Adv --| | | | | | | Figure 5. Nested Network Attachment - Signaling Flow Then the MAG sends the PBU message to the LMA to update its binding state. When the LMA receives the PBU message, the LMA registers MR1's identifier into MR2's or VMN's upper-router field in the BCE and updates the tunnel identifier field in the BCE. After the LMA sets up the BCE, the LMA sends the PBA message to the MAG. On receiving the PBA message, the MAG registers MR'1 identifier as the upper-router identifier in the Binding Update List Entry (BULE) that the MAG manages to maintain the binding state of a nemo. After that the MAG sets up the routing table to the nested nemo. MR1 receives the Nested Binding Acknowledgement (NBA) message that the MAG sends to MR1 and updates the NEMO State Table. MR1 has the mobility information of the mobile nodes attached to MR1 in the NEMO State Table. When MR3 or a VMN attaches to MR2, a recursive procedure is needed to update upper router's NEMO State Table, the BULE, and the BCE. MR2 sends the NBU message to its upper router (MR1). MR1 receives the NBU message and creates the NEMO State Table related to MR3 or the VMN. Then MR1 sends the Proxy Nested Binding Update (PNBU) message to the MAG. After the LMA and the MAG finish their process, MR1 receives the Proxy Nested Binding Acknowledgement (PNBA) message. Then MR1 updates its NEMO State Table and sets up the routing table. MR1 sends the NBA message to MR2. MR2 updates its NEMO State Table after receiving the NBA message. Figure 6 shows the handoff procedure when a nemo is nested. Even if a nemo is nested, the handoff procedure is the same as the non-nested case. The LMA and the MAG also update the entries for the nodes in the nested nemo. When the LMA and the MAG receive the signaling message such as the PBU, they check all entries in its binding table. Arita, et al Expires March 2011 [Page 9]
Internet Draft Proxy Network Mobility Protocol October 12, 2010 If an identifier in the upper router field equals to the Mobile Node Identifier option in the signaling message, the LMA and the MAG find that this entry must be updated. +-----+ +-----+ +-----+ +-----+ | VMN | | MR2 | | MR1 | | MAG | +-----+ +-----+ +-----+ +-----+ | | | | Attach Event | | | | Detect Attach event | | | | | | |- Rtr Sol -->| | | | |-- NBU --------->| | | | |-- PNBU ----------->| | | | |- PBU -> | | | | | | |<----------- PNBA --| | |<--------- NBA --| | |<- Rtr Adv --| | | | | | | Figure 6. Nested Mobile Network - Signaling Flow 4. Local Mobility Anchor Operation In order to manage the binding states of the MR and the VMN, some new functions MUST be added to the LMA. The LMA MUST have the function that allocates and manages the MNP. In order to forward the packets to LFN's address configured using the MNP, the LMA MUST intercept the packets destined to the MNP. To update the BCEs for the MR and the VMN in the nested nemo, the format of the PBU and the PBA messages MUST be extended. The PBU and the PBA message MUST have the Mobile Network Prefix option. This option informs the LMA and the MAG of the prefixes that are allocated to the nemo. The PBU and the PBA messages MUST also have the Upper Mobile Router option. This option informs the LAM and the MAG of the identifier of the upper MR to which the VMN and the MR are attached. The upper MR MUST be the MR that is attached to the MAG directly. The format of the BCE in the LMA MUST be extended to manage the MNP and the upper MR's identifier. The BCE has the R flag field in order to indicate whether or not this BCE is created for a MR or a single node. For a MR, this flag is set to value 1 and is set to value 0 for Arita, et al Expires March 2011 [Page 10]
Internet Draft Proxy Network Mobility Protocol October 12, 2010 a single node. The BCE in the LMA also has the Mobile Network Prefix field to manage the MNP. Besides, the BCE in the LMA has the Upper Mobile Router field. In the nested nemo scenario, if the LMA receives the signaling messages such as the PBU including the MR's identifier, the LMA updates the BCE for MR's identifier and the BCE whose upper router field equals to the MR's identifier. The LMA can manage the mobility of the nested nemo. 5. Mobile Access Gateway Operation In order to manage the binding states of the MR and the VMN, some new functions MUST be added to the MAG. The format of the BULE MUST be extended to manage the mobility of the nemo and the nested nemo. The Mobile Network Prefix field, the Upper Mobile Router field and the R flag must be added to the BULE in the MAG. If the R flag in the BULE is set to value 1, the entry is for a MR. If this R flag in the BULE is set to value 0, the entry is for a single node. The identifier of the Upper Mobile Router Identifier option in the signaling message from the MR is stored into the upper mobile router field. In order to manage the mobility of the nested nemo, PNEMO defines the following new signaling messages, the Nested Binding Update (NBU), the Netsted Binding Acknowledgement (NBA), the Proxy Nested Binding Update (PNBU) and the Proxy Nested Binding Acknowledgement (PNBA). Figure 7. shows the formats of the new signaling messages. The NBU and the NBA have the P flag and some Mobility options. If the P flag is set to value 1, this signaling message is called the PNBU or the PNBA. The NBU and the PNBU have the Mobile Node Identifier option, the Home Network Prefix option, the Mobile Network Prefix option and the Upper Mobile Router Identifier option as the Mobility Options. The NBA and the PNBA have the Mobile Node Identifier option, the Home Network Prefix option, the Mobile Network Prefix option as the Mobility Options and the P flag. Arita, et al Expires March 2011 [Page 11]
Internet Draft Proxy Network Mobility Protocol October 12, 2010 Nested Binding Update Massage 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 # | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P| Reserved | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Mobility options . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Nested Binding Acknowledgement 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 |P| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence # | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Mobility options . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7. A Format of New Signaling Messages Arita, et al Expires March 2011 [Page 12]
Internet Draft Proxy Network Mobility Protocol October 12, 2010 +-----+ | LMA | +-----+ | +-----+ | MAG | +-----+ | +-----+ +------| MR1 |--------+ | +-----+ | | | | | +-----+ | | +--| MR2 |----+ | | | +-----+ | | | | | | | | | +-----+ | | | |+-| MR3 |--+ | | | || +-----+ | | | | |+----------+ | | | +-------------+ | +---------------------+ Figure 8. An Example of a Nested NEMO Figure 8 shows an example of a nested nemo. When the MAG receives the NBU message from MR1 after MR2 is attached to MR1, the MAG creates an entry for MR2 in the BULE. The MAG registers the identifier of MR2 in the Mobile Node Identifier option with the Mobile Node Identifier field in this entry and registers the identifier and the link local address of MR1 with the Upper Mobile Router field and the Linklocal Address field in this entry, respectively. After authentication, the MAG sends the PBU message to its LMA. If the MR3 is attached to MR2, the MAG receives the PNBU message from MR1. As the MAG receives the NBU message, it sets up the binding states. Then the MAG sends the PBU message to its LMA. The LMA sends the PBA message containing the HNP and the MNP to allocate them to the nested nemo. After the MAG receives the PBA message, it updates entries for MR2 and MR3. Then the MAG sends the NBA or the PNBA message to MR1. 6. Mobile Router Operation Each MR MUST have the NEMO State Table (NST) to manage the location of the nested nemo. The NST has the Mobile Node Identifier field, the Arita, et al Expires March 2011 [Page 13]
Internet Draft Proxy Network Mobility Protocol October 12, 2010 Home Network Prefix field, the Mobile Network Prefix field, the Mobile Node Linklocal Address field and the Upper Mobile Router field. The Mobile Node Identifier field has the identifier of the nested MR (e.g., MR2) attached to the MR (e.g., MR1). The Home Network Prefix field and the Mobile Network Prefix field have the prefixes that are allocated to the nested nemo. The link local address in the Mobile Node Linklocal Address field is the next hop node's link local address to the HNP and MNP. MR's identifier in the Upper Mobile Router field is the next hop node's identifier to the destination. The signaling flow of the nested nemo is shown below. In Figure 8, MR1 is connected to the MAG and MR2 is connected to MR1. When MR3 is attached to MR2, MR3 sends the Router Solicitation (RS) message to MR2. MR2 detects MR3's attachment and creates the NST for MR3. MR2 sends the NBU message whose Mobile Node identifier option is set to the identifier of MR3 and whose Upper Mobile Router option is set the identifier of MR2 to MR1. After MR1 receives the NBU message, MR1 creates an entry for MR3 in the NST. Its Mobile Node Identifier field is set to the identifier of MR3 and its Upper Mobile Router field is set to the identifier of MR2. Then MR1 sends the PNBU message containing MR1's identifier in its Upper Mobile Router option to the MAG. After the MAG updates its BULE and the LMA updates its BCE, the MAG sends the PNBA message to MR1. When MR1 receives the PNBA message, it sets a lifetime in its NST. Then MR1 sends the NBA message to MR2. MR2 updates its NST and extracts the HNP and the MNP from the NBA message. Then the MR2 sends the Router Advertisement (RA) message to advertise the HNP and the MNP to MR3. MR3 configures its address using the HNP and sends the RA message with the MNP to its network. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3775] D. Johnson, "Mobility Support in IPv6", RFC 3775, June 2004. [RFC3963] V. Devarapalli, "Network Mobility (NEMO) Basic Support Arita, et al Expires March 2011 [Page 14]
Internet Draft Proxy Network Mobility Protocol October 12, 2010 Protocol", RFC 3963, January 2005. [RFC5213] S. Gundavelli, Ed. "Proxy Mobile IPv6", RFC 5213, August 2008. Authors' Addresses Tetsuya Arita Graduate School of Science and Technology, KEIO University 3-14-1 Hiyoshi, Kohoku-ku Yokohama, Kanagawa 223-8522 Japan Phone: +81-45-566-1425 EMail: cream@tera.ics.keio.ac.jp URI: http://www.tera.ics.keio.ac.jp/ Fumio Teraoka Faculty of Science and Technology, KEIO University 3-14-1 Hiyoshi, Kohoku-ku Yokohama, Kanagawa 223-8522 Japan Phone: +81-45-566-1425 EMail: tera@ics.keio.ac.jp URI: http://www.tera.ics.keio.ac.jp/ Arita, et al Expires March 2011 [Page 15]