Enhanced Mobility Anchoring in Distributed Mobility Management
draft-yhkim-dmm-enhanced-anchoring-00

DMM WG                                                    Younghan Kim
Internet Draft                                     Soongsil University
Intended status: Standard Track                         Seil Jeon, Ed.
Expires: April 27, 2015                  Institute de Telecomunicacoes
                                                      October 27, 2014

       Enhanced Mobility Anchoring in Distributed Mobility Management
                 draft-yhkim-dmm-enhanced-anchoring-00.txt

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Abstract

   This document presents a new perspective for the solution design of
   enhanced mobility anchoring in a distributed mobility management
   deployment. Mobility anchor function is composed of forwarding
   statement management and forwarding path management functions. In
   this draft, enhanced mobility anchoring solution design is discussed
   in the two cases: co-located forwarding state and path management
   functions on the same network entity and separated forwarding state
   and path management functions on different network entities.

Table of Contents

   1. Introduction ................................................ 2
   2. Conventions and Terminology ................................. 3
   3. Cases ....................................................... 3
      3.1. Case 1: Co-located forwarding state and path management
      functions on the same network entity (MR) ................... 3
      3.2. Case 2: Separated forwarding state and path management
      functions on different network entities ..................... 4
   4. Security Considerations ..................................... 5
   5. IANA Considerations ......................................... 5
   6. References .................................................. 6
      6.1. Normative References ................................... 6
      6.2. Informative References ................................. 6

1. Introduction

   This document presents a new perspective for the solution design of
   enhanced mobility anchoring in a distributed mobility management
   deployment.

   [RFC 7333] defines the requirements for distributed mobility
   management (DMM), in order to fundamentally address the scalability
   issues derived from a centralized mobility management (CMM)
   deployment. Based on the given requirements, there may have diverse
   design solutions for enhancing mobility anchoring, depending on a
   view point looking at mobility anchor function.

   Mobility anchor is composed of forwarding statement management and
   forwarding path management functions, where the former is
   responsible for creating and managing binding cache management while
   the latter is responsible for managing the forwarding paths using
   such as tunneling or non-tunneling interface. Each function can be
   co-located on a same network entity or separated on different

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   network entities for flexible deployment or efficient network
   operation.

   With the granularity of specified mobility anchor function, enhanced
   mobility anchoring solution design is discussed.

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 [RFC2119].

   Mobility router (MR) denotes a network entity, which has mobility
   access and anchor functionality. Additionally, we use the following
   term:

   Forwarding state management function (FSMF): is responsible for
   creating and managing a binding cache entry, until the terminal's
   session/flow is closed.

   Forwarding path management function (FPMF): is responsible for
   managing forwarding path using a tunnel or non-tunnel interface, to
   forward the packet destined to an assigned IP or prefix. The
   forwarding rule should be obtained from FSMF and is managed
   stateless.

3. Cases

3.1. Case 1: Co-located forwarding state and path management functions
   on the same network entity (MR)

             -------------          PBU           -------------
            |    (MR)     |  ----------------->  |    (MR)     |
            | FSMF + FPMF |  <-----------------  | FSMF + FPMF |
             -------------          PBA           -------------
                  |
                |  |
   (indication) |  |
                |
               ------
              |  MN  |
               ------

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                  Figure 1 Co-located FSMF and FPMF model

   In this case, FSM and FPM are co-located at MRs. When an MN is
   attached at an MR, the MR should be able to assign IP prefix on its
   address pool and manage binding cache associated with the assigned
   IP prefix. When anchor switching is needed (for load-balancing or
   optimal routing after the MN's handover), the MR (left) initiates an
   anchor switching procedure, sending Proxy Binding Update (PBU)
   signaling message including the forwarding state associated with the
   MN's flow to another MR (right) as shown in Figure 1. In [PMIP.MSR],
   an anchor switching mechanism was proposed with the name of mobility
   session redirection, over a Proxy Mobile IPv6 (PMIPv6) domain,
   specifying signaling and associated operation for LMA switching. It
   may belong to this case, though it follows centralized mobility
   management.

   In this case, each MR should be involved in negotiation for anchor
   switching and have a target MR selection algorithm, which leads to
   more signaling and complex processing.

3.2. Case 2: Separated forwarding state and path management functions
   on different network entities

                   ----------------------
                  |  FSMF (Controller)   |
                   ----------------------
                     |                |
                   |  |              |  |
                PBU|  |PBA        PBA|  |PBU
                   |                |
                ----------         ----------
               | FPMF (MR)|       | FPMF (MR)|
                ----------         ----------
                     |
                   |  |
      (indication) |  |
                   |
                  ------
                 |  MN  |
                  ------

                  Figure 2 Separated FSMF and FPMF model

   In this case, MRs have the forwarding path management function only.
   There is a dedicated and centralized network entity working as a

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   controller for anchor switching, as well as being in charge of IP or
   prefix assignment and management of binding cache entry.

   When an MN enters a distributed mobility management domain, it
   accesses FSM to get a new IP or prefix, which can be determined
   based on attached location of the MR. The assigned IP or prefix is
   delivered to the requested MR, and the MR then applies the received
   IP or prefix to the forwarding table.

   When anchor switching is needed, there are no signaling interactions
   between the former MR and new MR but between the related MRs and
   controller, since the controller is in charge of the anchor
   switching operation. As shown in Figure 2, the requesting MR (left)
   sends PBU signaling message, defined in [RFC5213], to controller
   with the forwarding state associated with the MN. The controller
   then checks an available MR (or based on a designated MR received
   from the requesting MR), and delivers the forwarding state to an MR
   (right). The MR (right) applies the forwarding rule between the MRs
   by sending PBU signaling message and sends back a PBA signaling
   message by the reverse path.

   For smooth path transition during the anchor switching, a transient
   tunneling could be established between the two MRs until a new
   routing path is established. When the routing path is made, the
   forwarding table applied in the previous MR is deleted.

   This deployment makes MRs lightweight for anchor switching,
   controlled by a central entity managing forwarding state and
   monitoring load status at each MR.

4. Security Considerations

   T.B.D.

5. IANA Considerations

   T.B.D.

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6. References

6.1. Normative References

   [RFC2119] S. Bradner, "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC7333] H. Chan, D. Liu, P. Seite, H. Yokota, and J. Korhonen,
             "Requirements for Distributed Mobility Management," IETF
             RFC 7333, Aug. 2014.

   [RFC5213] S. Gundavelli, K. Leung, V. Devarapalli, K. Chowdury, and
             B.Patil, "Proxy Mobile IPv6," IETF RFC 5213, Aug. 2008.

6.2. Informative References

   [PMIP.MSR]S. Jeon and Y. Kim, "Proxy Mobile IPv6 with Mobility
             Session Redirection," draft-sijeon-netext-pmip-msr-01, Jul.
             2014.

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   Authors' Addresses

   Younghan Kim
   Soongsil University
   369, Sangdo-ro, Dongjak-gu,
   Seoul 156-743, Korea

   younghak@ssu.ac.kr

   Seil Jeon (Editor)
   Instituto de Telecomunicacoes
   Campus Universitario de Santiago
   Aveiro 3810-193, Portugal

   seiljeon@av.it.pt

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