DMM WG Younghan Kim Internet Draft Soongsil University Intended status: Standard Track Seil Jeon, Ed. Expires: September 23, 2015 Institute de Telecomunicacoes March 23, 2015 Enhanced Mobility Anchoring in Distributed Mobility Management draft-yhkim-dmm-enhanced-anchoring-01.txt 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 September 23, 2015. Copyright Notice Copyright (c) 2015 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. Jeon et al. Expires September 22, 2015 [Page 1] Internet-Draft Enhanced Anchoring in DMM March 2015 Abstract This document presents a new perspective for the solution design of enhanced mobility anchoring in a distributed mobility management deployment. Based on the definition of anchor function, location management function, and forwarding management function in RFC7429, we propose four cases of distributed deployment models and enhanced anchoring models over them. Table of Contents 1. Introduction ................................................. 2 2. Conventions and Terminology .................................. 3 3. Enhanced Anchoring Models .................................... 3 3.1. Case 1: Distributed AM, LM, and FM functions (All-in-One) 4 3.2. Case 2: Distributed LM and FM functions with centralized AF .................................................. 5 3.3. Case 3: Distributed AF and FM functions with centralized LM .................................................. 6 3.4. Case 4: Distributed FM function with centralized AF and LM7 4. Security Considerations ...................................... 7 5. IANA Considerations .......................................... 8 6. References ................................................... 8 6.1. Normative References .................................... 8 1. Introduction This document presents a new perspective for the solution design of enhanced mobility anchoring in a distributed mobility management deployment. [RFC7333] 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. [RFC7429] specifies mobility management functions with three roles: anchoring functions (AF), internetwork location management (LM) function, and forwarding management (FM) function. Jeon et al. Expires September 22, 2015 [Page 2] Internet-Draft Enhanced Anchoring in DMM March 2015 Based on the given definitions of mobility management functions, a mobility anchor node can be considered. Basically, a mobility router needs to have the FM function for data distribution over a mobile network, while deployment of the other functions such as AF and LM can be considered with combinatorial cases. That is, FM is distributed while AF and LM can be distributed or centralized. Taking those deployment combinations, we provide four deployment models for anchor switching. 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. Specifically, the entity is split into following functions, defined in [RFC7429]. Anchoring Function (AF) is a control-plane function, which allocates an IP address, i.e., Home Address (HoA), or prefix, i.e., Home Network Prefix (HNP) a mobile node, topologically anchored by the advertising node. That is, the anchor node is able to advertise a connected route into the routing infrastructure for the allocated IP prefixes. Internetwork Location Management (LM) is a control-plane function, which manages and keeps track of the internetwork location of an MN. The location information may be a binding of the advertised IP address/prefix, e.g., HoA or HNP, to the IP routing address of the MN, or it may be a binding of a node that can forward packets destined to the MN. Forwarding Management (FM) function performs packet interception and forwarding to/from the IP address/prefix assigned to the MN, based on the internetwork location information, either to the destination or to some other network element that knows how to forward the packets to their destination. 3. Enhanced Anchoring Models FM is distributed over MRs deployed at the edges while AM and LM are distributed or centralized. Taking into consideration the deployment of the mobility management functions, four cases of the function deployment for anchor switching are given. Jeon et al. Expires September 22, 2015 [Page 3] Internet-Draft Enhanced Anchoring in DMM March 2015 3.1. Case 1: Distributed AM, LM, and FM functions (All-in-One) ------------- anchor switching req. ------------- | (MR) | -----------------+ | (MR) | |AR + LM + FM | +----------------- |AR + LM + FM | ------------- anchor switching res. ------------- + | | | (indication) | | (Response to the indication) | + ------ | MN | ------ Figure 1 Distributed AM, LM, and FM functions In this case, LM and FM functions are co-located at MRs. When an MN is attached at an MR, the MR should be able to assign IP address or prefix on its address pool by AR and manage binding cache associated with the assigned IP prefix by LM. 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 anchor switching request message including the binding context associated with the MN's flow to another MR (right) as shown in Figure 1. If the target MR is available to accept the anchor switching request, it sends back anchor switching response message to the request MR. Employed signaling message can be implemented through extension of existing mobility signaling message such as Proxy Binding Update (PBU) and Proxy Binding Acknowledgment (PBA) messages in PMIPv6. 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. Jeon et al. Expires September 22, 2015 [Page 4] Internet-Draft Enhanced Anchoring in DMM March 2015 3.2. Case 2: Distributed LM and FM functions with centralized AF ----------- | AF | ----------- + + (mobility signaling / \ (mobility signaling or DHCP to get / \ or DHCP to get an IP address) / \ an IP address) / \ + + ------------- anchor switching req. ------------- | (MR) | -----------------+ | (MR) | | LM + FM | +----------------- | LM + FM | ------------- anchor switching res. ------------- + | | | (indication) | | (Response to the indication) | + ------ | MN | ------ Figure 2 Distributed LM and FM functions with centralized AF In this case, LM and FM functions are co-located at MRs while AF is deployed in the form of centralization. When an MN is attached at an MR, the MR needs to get an IP address or prefix from the AF. For this operation, an extended binding update signaling from IP mobility protocols or DHCP can be used. The rest of functions and operations follow the same procedures described in Case 1. Jeon et al. Expires September 22, 2015 [Page 5] Internet-Draft Enhanced Anchoring in DMM March 2015 3.3. Case 3: Distributed AF and FM functions with centralized LM ---------------------------- | LM | ---------------------------- + | + | anchor | | anchor anchor | | anchor switching| |switching switching| |switching req. | + res. res. | + req. ---------- ---------- | AF+FM(MR)| | AF+FM(MR)| ---------- ---------- + | | | (indication) | | (Response to the indication) | + ------ | MN | ------ Figure 3 Distributed AF and FM with centralized LM In this case, MRs have the AF and FM functions. There is a dedicated and centralized network entity working as a 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 gets a new IP or prefix from an AF. 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 in the FM. 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 3, the requesting MR (left) sends an anchor switching request message, defined in [RFC5213], including the binding context associated with the MN to controller. The controller then checks an available MR (or based on a designated MR received from the requesting MR), and delivers the binding context to an MR (right). The MR (right) applies the forwarding rule between the MRs by sending the anchor switching request message and sends back the anchor switching response message through the reverse path. Jeon et al. Expires September 22, 2015 [Page 6] Internet-Draft Enhanced Anchoring in DMM March 2015 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. Such deployment makes MRs lightweight for anchor switching, controlled by a central entity managing forwarding state and monitoring load status at each MR. 3.4. Case 4: Distributed FM function with centralized AF and LM --------- ---------------- | AF | | LM (Controller)| --------- ---------------- + + ++ ++ mobility | // || anchor switching signaling | // \ || req./res. or DHCP + ++ + ++ ---------- ---------- | FM (MR)| | FM (MR) | ---------- ---------- + | | | (indication) | | (Response to the indication) | + ------ | MN | ------ Figure 4 Distributed FM with centralized AF and LM In this case, MRs have the forwarding path management function only. AF and LM are deployed in a centralized form. When an MN enters a distributed mobility management domain, it gets a new IP or prefix from the AF, 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 in FM. When anchor switching is needed, it follows the same procedures described in case 3. 4. Security Considerations T.B.D. Jeon et al. Expires September 22, 2015 [Page 7] Internet-Draft Enhanced Anchoring in DMM March 2015 5. IANA Considerations T.B.D. 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. [RFC7429] D. Liu, JC. Zuniga, P. Seite, H. Chan, CJ. Bernardos, "Distributed Mobility Management: Current Practices and Gap Analysis," IETF 7429, Jan. 2015. Jeon et al. Expires September 22, 2015 [Page 8] Internet-Draft Enhanced Anchoring in DMM March 2015 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 Jeon et al. Expires September 22, 2015 [Page 9]