--- 1/draft-ietf-dmm-requirements-00.txt 2012-07-12 01:14:10.421758387 +0200 +++ 2/draft-ietf-dmm-requirements-01.txt 2012-07-12 01:14:10.453758812 +0200 @@ -1,18 +1,18 @@ Network Working Group H. Chan (Ed.) Internet-Draft Huawei Technologies -Intended status: Informational July 7, 2012 -Expires: January 8, 2013 +Intended status: Informational July 12, 2012 +Expires: January 13, 2013 Requirements of distributed mobility management - draft-ietf-dmm-requirements-00 + draft-ietf-dmm-requirements-01 Abstract The traditional hierarchical structure of cellular networks has led to deployment models which are heavily centralized. Mobility management with centralized mobility anchoring in existing hierarchical mobile networks is quite prone to suboptimal routing and issues related to scalability. Centralized functions present a single point of failure, and inevitably introduce longer delays and higher signaling loads for network operations related to mobility @@ -32,43 +32,44 @@ 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 8, 2013. + This Internet-Draft will expire on January 13, 2013. Copyright Notice Copyright (c) 2012 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions used in this document . . . . . . . . . . . . . . 5 + 2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5 3. Centralized versus distributed mobility management . . . . . . 5 - 3.1. Centralized mobility management . . . . . . . . . . . . . 5 + 3.1. Centralized mobility management . . . . . . . . . . . . . 6 3.2. Distributed mobility management . . . . . . . . . . . . . 6 4. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1. Distributed deployment . . . . . . . . . . . . . . . . . . 8 4.2. Transparency to Upper Layers when needed . . . . . . . . . 9 4.3. IPv6 deployment . . . . . . . . . . . . . . . . . . . . . 10 4.4. Compatibility . . . . . . . . . . . . . . . . . . . . . . 10 4.5. Existing mobility protocols . . . . . . . . . . . . . . . 11 4.6. Security considerations . . . . . . . . . . . . . . . . . 11 5. Security Considerations . . . . . . . . . . . . . . . . . . . 12 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 @@ -147,51 +148,67 @@ launch and complete while the mobile device is connected to the same point of attachment. However, the mobility support has been designed to be always on and to maintain the context for each mobile subscriber as long as they are connected to the network. This can result in a waste of resources and ever-increasing costs for the service provider. Infrequent mobility and intelligence of many applications suggest that mobility can be provided dynamically, thus simplifying the context maintained in the different nodes of the mobile network. - The proposed charter will address two complementary aspects of - mobility management procedures: the distribution of mobility anchors - to achieve a more flat design and the dynamic activation/deactivation - of mobility protocol support as an enabler to distributed mobility + The DMM charter addresses two complementary aspects of mobility + management procedures: the distribution of mobility anchors to + achieve a more flat design and the dynamic activation/deactivation of + mobility protocol support as an enabler to distributed mobility management. The former has the goal of positioning mobility anchors (HA, LMA) closer to the user; ideally, these mobility agents could be collocated with the first hop router. The latter, facilitated by the distribution of mobility anchors, aims at identifying when mobility must be activated and identifying sessions that do not impose mobility management -- thus reducing the amount of state information to be maintained in the various mobility agents of the mobile network. The key idea is that dynamic mobility management relaxes - some constraints while also repositioning mobility anchors; it avoids - the establishment of non optimal tunnels between two topologically - distant anchors. + some constraints so that it may avoid the establishment of non- + optimal tunnels between two topologically distant anchors. This document describes the motivations of distributed mobility management in Section 1. Section 3 compares distributed mobility management with centralized mobility management. The requirements to address these problems are given in Section 4. The problem statement and the use cases [I-D.yokota-dmm-scenario] can be found in the following review paper: [Paper- Distributed.Mobility.Review]. 2. 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]. +2.1. Terminology + + All the general mobility-related terms and their acronyms used in + this document are to be interpreted as defined in the Mobile IPv6 + base specification [RFC6275], in the Proxy mobile IPv6 specification + [RFC5213], and in Mobility Related Terminology [RFC3753]. These + terms include mobile node (MN), correspondent node (CN), home agent + (HA), local mobility anchor (LMA), mobile access gateway (MAG), and + context. + + In addition, this draft introduces the following term. + + Mobility context + + is the collection of information required to provide mobility + support for a given mobile node. + 3. Centralized versus distributed mobility management Mobility management functions may be implemented at different layers of the network protocol stack. At the IP (network) layer, they may reside in the network or in the mobile node. In particular, a network-based solution resides in the network only. It therefore enables mobility for existing hosts and network applications which are already in deployment but lack mobility support. At the IP layer, a mobility management protocol to achieve session @@ -233,21 +249,21 @@ UMTS 3GPP SAE MIP/PMIP +------+ +------+ +------+ | GGSN | | P-GW | |HA/LMA| +------+ +------+ +------+ /\ /\ /\ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ +------+ +------+ +------+ +------+ +------+ +------+ - | SGSN | | SGSN | | S-GW | | S-GW | |FA/MAG| |FA/MAG| + | SGSN | | SGSN | | S-GW | | S-GW | |MN/MAG| |MN/MAG| +------+ +------+ +------+ +------+ +------+ +------+ Figure 1. Centralized mobility management. 3.2. Distributed mobility management Mobility management functions may also be distributed to multiple locations in different networks as shown in Figure 2, so that a mobile node in any of these networks may be served by a closeby mobility function (MF). @@ -269,21 +285,21 @@ [Paper-New.Perspective] discusses some initial steps towards a clear definition of what mobility management may be, to assist in better developing distributed architecture. [Paper- Characterization.Mobility.Management] analyses current mobility solutions and proposes an initial decoupling of mobility management into well-defined functional blocks, identifying their interactions, as well as a potential grouping, which later can assist in deriving more flexible mobility management architectures. According to the split functional blocks, this paper proposes three ways into which - mobility management functional blocks can be groups, as an initial + mobility management functional blocks can be grouped, as an initial way to consider a better distribution: location and handover management, control and data plane, user and access perspective. A distributed mobility management scheme is proposed in [Paper- Distributed.Dynamic.Mobility] for future flat IP architecture consisting of access nodes. The benefits of this design over centralized mobility management are also verified through simulations in [Paper-Distributed.Centralized.Mobility]. Before designing new mobility management protocols for a future flat @@ -295,55 +311,37 @@ Using MIP or PMIP for both centralized and distributed architectures would ease the migration of the current mobile networks towards a flat architecture. It has therefore been proposed to adapt MIP or PMIPv6 to achieve distributed mobility management by using a distributed mobility anchor architecture. In [Paper-Migrating.Home.Agents], the HA functionality is copied to many locations. The HoA of all MNs are anycast addresses, so that a packet destined to the HoA from any corresponding node (CN) from any network can be routed via the nearest copy of the HA. In addition, - distributing the function of HA using a distributed hash table - structure is proposed in [Paper-Distributed.Mobility.SAE]. A lookup - query to the hash table will retrieve the location information of an - MN is stored. - - In [Paper-Distributed.Mobility.PMIP], only the mobility routing (MR) - function is duplicated and distributed in many locations. The - location information for any MN that has moved to a visited network - is still centralized and kept at a location management (LM) function - in the home network of the MN. The LM function at different networks - constitutes a distributed database system of all the MNs that belong - to any of these networks and have moved to a visited network. The - location information is maintained in the form of a hierarchy: the LM - at the home network, the CoA of the MR of the visited network, and - then the CoA to reach the MN in the visited network. The LM in the - home network keeps a binding of the HoA of the MN to the CoA of the - MR of the visited network. The MR keeps the binding of the HoA of - the MN to the CoA of the MN in the case of MIP, or the proxy-CoA of - the Mobile Access Gateway (MAG) serving the MN in the case of PMIP. - - [I-D.jikim-dmm-pmip] discusses two distributed mobility control - schemes using the PMIP protocol: Signal-driven PMIP (S-PMIP) and - Signal-driven Distributed PMIP (SD-PMIP). S-PMIP is a partially - distributed scheme, in which the control plane (using a Proxy Binding - Query to get the Proxy-CoA of the MN) is separate from the data - plane, and the optimized data path is directly between the CN and the - MN. SD-PMIP is a fully distributed scheme, in which the Proxy - Binding Update is not performed, and instead each MAG will multicast - a Proxy Binding Query message to all of the MAGs in its local PMIP - domain to retrieve the Proxy-CoA of the MN. + [Paper-Distributed.Mobility.SAE] proposes to distribute the function + of HA into many mobility agents (MAs) each serving a portion of MNs + using a distributed hash table structure. A lookup to the hash table + will point to the MA serving an MN. In [Paper- + Distributed.Mobility.PMIP] and [Paper-Distributed.Mobility.MIP], only + the mobility routing (MR) function is duplicated and distributed in + many locations. The location information for any MN that has moved + to a visited network is still centralized and kept at a location + management (LM) function in the home network of the MN. The LM + function at different networks constitutes a distributed database + system of all the MNs that belong to any of these networks and have + moved to a visited network. 4. Requirements - After reviewing the problems and limitations of centralized - deployment in Section 4, this section states the requirements as + After comparing distributed mobility management against centralized + deployment in Section 3, this section states the requirements as follows: 4.1. Distributed deployment REQ1: Distributed deployment IP mobility, network access and routing solutions provided by DMM MUST enable a distributed deployment of mobility management of IP sessions so that the traffic can be routed in an optimal manner without traversing centrally deployed @@ -392,22 +390,22 @@ The DMM solutions MUST provide transparency above the IP layer when needed. Such transparency is needed, when the mobile hosts or entire mobile networks [RFC3963] change their point of attachment to the Internet, for the application flows that cannot cope with a change of IP address. Otherwise the support to maintain a stable home IP address or prefix during handover may be declined. Motivation: The motivation of this requirement is to enable more efficient use of network resources and more efficient - routing by not maintaining a stable IP home IP address when - there is no such need. + routing by not maintaining a stable home IP address when there + is no such need. This requirement addresses the problems PS5 as well as the other related problem O-PS1. PS5: Wasting resources to support mobile nodes not needing mobility support IP mobility support is not always required. For example, some applications do not need a stable IP address during handover, i.e., IP session continuity. Sometimes, the entire application @@ -441,59 +439,60 @@ 4.4. Compatibility REQ4: Compatibility The DMM solution SHOULD be able to work between trusted administrative domains when allowed by the security measures deployed between these domains. Furthermore, the DMM solution MUST be able to co-exist with existing network deployment and end hosts so that the existing deployment can continue to be supported. For example, depending on the environment in which - dmm is deployed, the dmm solutions may need to be compatible + DMM is deployed, the DMM solutions may need to be compatible with other existing mobility protocols that are deployed in that environment or may need to be interoperable with the network or the mobile hosts/routers that do not support the - dmm enabling protocol. + DMM enabling protocol. Motivation: The motivation of this requirement is to allow inter-domain operation if desired and to preserve backwards compatibility so that the existing networks and hosts are not affected and do not break. This requirement addresses the following other related problem O-PS2. O-PS2: Complicated deployment with too many variants and extensions - of MIP Deployment is complicated with many variants and - extensions of MIP. When introducing new functions which may - add to the complicity, existing solutions are more vulnerable - to break. + of MIP + + Deployment is complicated with many variants and extensions + of MIP. When introducing new functions which may add to the + complexity, existing solutions are more vulnerable to break. 4.5. Existing mobility protocols REQ5: Existing mobility protocols A DMM solution SHOULD first consider reusing and extending the existing mobility protocols before specifying new protocols. Motivation: The purpose is to reuse the existing protocols first before considering new protocols. 4.6. Security considerations REQ6: Security considerations The protocol solutions for DMM MUST consider security, for example authentication and authorization mechanisms that allow a legitimate mobile host/router to access to the DMM service, protection of signaling messages of the protocol solutions in terms of authentication, data integrity, and data - confidentiality, opti-in or opt-out data confidentiality to + confidentiality, opt-in or opt-out data confidentiality to signaling messages depending on network environments or user requirements. Motivation and problem statement: Mutual authentication and authorization between a mobile host/router and an access router providing the DMM service to the mobile host/router are required to prevent potential attacks in the access network of the DMM service. Otherwise, various attacks such as impersonation, denial of service, man-in-the-middle attacks, etc. are present to obtain illegitimate access or to collapse @@ -539,80 +538,87 @@ Pierrick Seite: pierrick.seite@orange-ftgroup.com Hidetoshi Yokota: yokota@kddilabs.jp Charles E. Perkins: charliep@computer.org Melia Telemaco: telemaco.melia@alcatel-lucent.com Elena Demaria: elena.demaria@telecomitalia.it + Peter McCann: Peter.McCann@huawei.com Tricci So: tso@zteusa.com Jong-Hyouk Lee: jh.lee@telecom-bretagne.eu Jouni Korhonen: jouni.korhonen@nsn.com - - Wen Luo: luo.wen@zte.com.cn + Sri Gundavelli: sgundave@cisco.com Carlos J. Bernardos: cjbc@it.uc3m.es Marco Liebsch: Marco.Liebsch@neclab.eu - Georgios Karagian: karagian@cs.utwente.nl + Wen Luo: luo.wen@zte.com.cn + + Georgios Karagiannis: g.karagiannis@utwente.nl Julien Laganier: jlaganier@juniper.net Wassim Michel Haddad: Wassam.Haddad@ericsson.com Seok Joo Koh: sjkoh@knu.ac.kr + Dirk von Hugo: Dirk.von-Hugo@telekom.de + + Ahmad Muhanna: amuhanna@awardsolutions.com + 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 8.2. Informative References [I-D.ietf-netext-pd-pmip] Zhou, X., Korhonen, J., Williams, C., Gundavelli, S., and C. Bernardos, "Prefix Delegation for Proxy Mobile IPv6", draft-ietf-netext-pd-pmip-02 (work in progress), March 2012. - [I-D.jikim-dmm-pmip] - Kim, J., Koh, S., Jung, H., and Y. Han, "Use of Proxy - Mobile IPv6 for Distributed Mobility Control", - draft-jikim-dmm-pmip-00 (work in progress), March 2012. - [I-D.yokota-dmm-scenario] Yokota, H., Seite, P., Demaria, E., and Z. Cao, "Use case scenarios for Distributed Mobility Management", draft-yokota-dmm-scenario-00 (work in progress), October 2010. [Paper-Distributed.Centralized.Mobility] Bertin, P., Bonjour, S., and J-M. Bonnin, "A Distributed or Centralized Mobility", Proceedings of Global Communications Conference (GlobeCom), December 2009. [Paper-Distributed.Dynamic.Mobility] Bertin, P., Bonjour, S., and J-M. Bonnin, "A Distributed Dynamic Mobility Management Scheme Designed for Flat IP Architectures", Proceedings of 3rd International Conference on New Technologies, Mobility and Security (NTMS), 2008. + [Paper-Distributed.Mobility.MIP] + Chan, H., "Distributed Mobility Management with Mobile + IP", Proceedings of IEEE International Communication + Conference (ICC) Workshop on Telecommunications: from + Research to Standards, June 2012. + [Paper-Distributed.Mobility.PMIP] Chan, H., "Proxy Mobile IP with Distributed Mobility Anchors", Proceedings of GlobeCom Workshop on Seamless Wireless Mobility, December 2010. [Paper-Distributed.Mobility.Review] Chan, H., Yokota, H., Xie, J., Seite, P., and D. Liu, "Distributed and Dynamic Mobility Management in Mobile Internet: Current Approaches and Issues, Journal of Communications, vol. 6, no. 1, pp. 4-15, Feb 2011.", @@ -709,10 +715,14 @@ - Wen Luo ZTE No.68, Zijinhua RD,Yuhuatai District, Nanjing, Jiangsu 210012, China Email: luo.wen@zte.com.cn - Marco Liebsch NEC Laboratories Europe Email: liebsch@neclab.eu - + Carl Williams + MCSR Labs + Email: carlw@mcsr-labs.org + -