Network Working Group C. Shao Internet-Draft H. Deng Intended status: Standards Track China Mobile Expires: November 6, 2014 R. Pazhyannur Cisco Systems F. Bari AT&T R. Zhang China Telecom S. Matsushima SoftBank Telecom May 5, 2014 IEEE 802.11 MAC Profile for CAPWAP draft-ietf-opsawg-capwap-hybridmac-04 Abstract CAPWAP defines two entities: Wireless Transmission Point (WTP) and Access Controller (AC). CAPWAP also defines two MAC (Medium Access Control) modes for IEEE 802.11 WTPs: Split and Local MAC . For each MAC mode, CAPWAP describes how the MAC functionality is split between the WTP and AC. However, certain functions have not been clearly defined. For example in the Split MAC mode description, the IEEE 802.11 encryption is specified as located in either the AC or the WTP with no clear way for the AC to inform the WTP where it should be. This lack of specification leads to interoperability especially when AC and WTP come from different vendors. To solve the problem, this specification defines a IEEE 802.11 MAC profile where each profile specifies an unambiguous division of functionality between the WTP and AC. The IEEE 802.11 MAC profile is used as follows: the WTP informs the AC of the supported profiles during the discovery or join process and the AC configures the WTP with one of the supported profiles while configuring the WLAN. 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 Shao, et al. Expires November 6, 2014 [Page 1] Internet-Draft CAPWAP May 2014 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 November 6, 2014. Copyright Notice Copyright (c) 2014 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 . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions used in this document . . . . . . . . . . . . . . 4 3. IEEE MAC Profile Descriptions . . . . . . . . . . . . . . . . 4 3.1. Split MAC with WTP encryption . . . . . . . . . . . . . . 4 3.2. Split MAC with AC encryption . . . . . . . . . . . . . . 5 3.3. IEEE 802.11 MAC Profile Frame Exchange . . . . . . . . . 6 4. MAC Profile Message Element Definitions . . . . . . . . . . . 7 4.1. IEEE 802.11 Supported MAC Profiles . . . . . . . . . . . 7 4.2. IEEE 802.11 MAC Profile . . . . . . . . . . . . . . . . . 8 5. Security Considerations . . . . . . . . . . . . . . . . . . . 8 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 9 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 9. Normative References . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 1. Introduction The CAPWAP protocol supports two MAC modes of operation: Split and Local MAC, as described in [RFC5415], [RFC5416]. However, there are MAC functions that have not been clearly defined. For example IEEE 802.11 encryption is specified as located in either in the AC or the WTP with no clear way to negotiate where it should be located. Because different vendors have their own definition of the MAC mode, many MAC layer functions are mapped differently to either the WTP or the AC by different vendors. Therefore, depending upon the vendor, Shao, et al. Expires November 6, 2014 [Page 2] Internet-Draft CAPWAP May 2014 the operators in their deployments have to perform different configurations based on implementation of the two modes by their vendor. If there is no clear specification then operators will experience difficulty in interoperating WTPs and ACs from different vendors. Figure 1 is quoted from [RFC5416], illustrates how the functions are processed in different places in the Local MAC and Split MAC mode. Specifically, note that in the Split MAC mode the IEEE 802.11 encryption/decryption is specified as WTP/AC implying that it could be at either location. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Functions | Local MAC | Split MAC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Distribution Service | WTP/AC | AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Integration Service | WTP | AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Beacon Generation | WTP | WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Probe Response Generation| WTP | WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Function |Power Mgmt | WTP | WTP | + |/Packet Buffering | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Fragmentation | WTP | WTP/AC | + |/Defragmentation | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Assoc/Disassoc/Reassoc | WTP/AC | AC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Classifying | WTP | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 QoS |Scheduling | WTP | WTP/AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Queuing | WTP | WTP | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.1X/EWTP | AC | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 RSN |RSNA Key Management | AC | AC | + (WPA2) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.11 | WTP | WTP/AC | + |Encryption/Decryption | | | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: Functions in Local MAC and Split MAC Shao, et al. Expires November 6, 2014 [Page 3] Internet-Draft CAPWAP May 2014 To solve this problem, this specification introduces IEEE 802.11 MAC profile. The MAC profile unambiguously specifies where the various MAC functionality should be located. 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]. 3. IEEE MAC Profile Descriptions A IEEE MAC Profile refers to a description of how the MAC functionality is split between the WTP and AC shown in Figure 1. 3.1. Split MAC with WTP encryption The functional split for the Split MAC with WTP encryption is provided in Figure 2. This profile is similar to the Split MAC description in [RFC5416] except that IEEE 802.11 encryption/ decryption is at the WTP. Note that fragmentation is always done at the same entity as the encryption. Consequently, in this profile fragmentation/defragmentation is also done only at the WTP Note that scheduling functionality is denoted as WTP/AC. As explained in [RFC5416], this means that the admission control component of IEEE 802.11 resides on the AC, the real-time scheduling and queuing functions are on the WTP. Shao, et al. Expires November 6, 2014 [Page 4] Internet-Draft CAPWAP May 2014 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Functions | Profile | | | 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Distribution Service | AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Integration Service | AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Beacon Generation | WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Probe Response Generation| WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Function |Power Mgmt | WTP | + |/Packet Buffering | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Fragmentation | WTP | + |/Defragmentation | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Assoc/Disassoc/Reassoc | AC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Classifying | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 QoS |Scheduling | WTP/AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Queuing | WTP | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.1X/EWTP | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 RSN |RSNA Key Management | AC | + (WPA2) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.11 | WTP | + |Encryption/Decryption | | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: Functions in Split MAC with WTP Encryption 3.2. Split MAC with AC encryption The functional split for the Split MAC with AC encryption is provided in Figure 3. This profile is similar to the Split MAC in [RFC5416] except that IEEE 802.11 encryption/decryption is at the AC. Since fragmentation is always done at the same entity as the encryption, in this profile, AC does fragmentation/defragmentation. Shao, et al. Expires November 6, 2014 [Page 5] Internet-Draft CAPWAP May 2014 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Functions | Profile | | | 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Distribution Service | AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Integration Service | AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Beacon Generation | WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Probe Response Generation| WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Function |Power Mgmt | WTP | + |/Packet Buffering | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Fragmentation | AC | + |/Defragmentation | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Assoc/Disassoc/Reassoc | AC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Classifying | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 QoS |Scheduling | WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Queuing | WTP | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.1X/EWTP | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 RSN |RSNA Key Management | AC | + (WPA2) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.11 | AC | + |Encryption/Decryption | | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: Functions in Split MAC with AC encryption 3.3. IEEE 802.11 MAC Profile Frame Exchange An example of message exchange using the IEEE 802.11 MAC Profile message element is shown in Figure 4. The WTP informs the AC of the various MAC profiles it supports. This happens either in a Discovery Request message or the Join Request message. The AC determines the appropriate profile and configures the WTP with the profile while configuring the WLAN. Shao, et al. Expires November 6, 2014 [Page 6] Internet-Draft CAPWAP May 2014 +-+-+-+-+-+-+ +-+-+-+-+-+-+ | WTP | | AC | +-+-+-+-+-+-+ +-+-+-+-+-+-+ |Join Request[Supported IEEE 802.11 | | MAC Profiles ] | |---------------------------------------->| | | |Join Response | |<----------------------------------------| | | |IEEE 802.11 WLAN Config. Request [ | | IEEE 802.11 Add WLAN, | | IEEE 802.11 MAC Profile | | ] | |<----------------------------------------| | | |IEEE 802.11 WLAN Config. Response | |---------------------------------------->| Figure 4: Message Exchange For Negotiating MAC Profile 4. MAC Profile Message Element Definitions 4.1. IEEE 802.11 Supported MAC Profiles The IEEE 802.11 Supported MAC Profile message element allows the WTP to communicate the profiles it supports. The Discovery Request message, Primary Discovery Request message, and Join Request message may include one such message element. 0 1 2 3 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 +=+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- | Num_Profiles | Profile_1 | Profile_[2..N].. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- Figure 5: IEEE 802.11 Supported MAC Profiles o Type: TBD for IEEE 802.11 Supported MAC Profiles o Num_Profiles >=1: This refers to number of profiles present in this message element. There must be at least one profile. o Profile: Each profile is idnentified by a value specified in Section 4.2. Shao, et al. Expires November 6, 2014 [Page 7] Internet-Draft CAPWAP May 2014 4.2. IEEE 802.11 MAC Profile The IEEE 802.11 MAC Profile message element allows the AC to select a profile. This message element may be provided along with the IEEE 802.11 ADD WLAN message element while configuring a WLAN on the WTP. 0 1 2 3 4 5 6 7 +=+-+-+-+-+-+-+-+ | Profile | +-+-+-+-+-+-+-+-+ Figure 6: IEEE 802.11 MAC Profile o Type: TBD for IEEE 802.11 MAC Profile o Profile: The profile is identified by a value as given below * 0: This refers to the Split MAC Profile with WTP encryption * 1: This refers to the Split MAC Profile with AC encryption 5. Security Considerations This document does not introduce any new security risks compared to [RFC5416]. The security considerations described in [RFC5416] apply here as well. 6. IANA Considerations This document requires the following IANA actions. o This specification defines a new message element, IEEE 802.11 Supported MAC Profiles. The format of this option is described in Section 4.1. This value needs to be registered in the existing CAPWAP Message Element Type registry, defined in [RFC5415]. o This specification defines a new message element, IEEE 802.11 MAC Profile. The format of this option is described in Section 4.2. This value needs to be registered in the existing CAPWAP Message Element Type registry, defined in [RFC5415]. o The Profile field in the IEEE 802.11 Supported MAC Profiles message element and IEEE 802.11 MAC Profile message element (see Section 4.2) is used to denote the MAC profile. This document defines two values, zero (0) and one (1), and the remaining values (2-255) are controlled and maintained by IANA and require an Expert Review. Shao, et al. Expires November 6, 2014 [Page 8] Internet-Draft CAPWAP May 2014 7. Contributors Yifan Chen chenyifan@chinamobile.com Naibao Zhou zhounaibao@chinamobile.com 8. Acknowledgments The authors are grateful for extremely valuable suggestions from Dorothy Stanley in developing this specification. Guidance from management team: Melinda Shore, Scott Bradner, Chris Liljenstolpe, Benoit Claise, Joel Jaeggli, Dan Romascanu are highly appreciated. 9. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5415] Calhoun, P., Montemurro, M., and D. Stanley, "Control And Provisioning of Wireless Access Points (CAPWAP) Protocol Specification", RFC 5415, March 2009. [RFC5416] Calhoun, P., Montemurro, M., and D. Stanley, "Control and Provisioning of Wireless Access Points (CAPWAP) Protocol Binding for IEEE 802.11", RFC 5416, March 2009. Authors' Addresses Chunju Shao China Mobile No.32 Xuanwumen West Street Beijing 100053 China Email: shaochunju@chinamobile.com Hui Deng China Mobile No.32 Xuanwumen West Street Beijing 100053 China Email: denghui@chinamobile.com Shao, et al. Expires November 6, 2014 [Page 9] Internet-Draft CAPWAP May 2014 Rajesh S. Pazhyannur Cisco Systems 170 West Tasman Drive San Jose, CA 95134 USA Email: rpazhyan@cisco.com Farooq Bari AT&T 7277 164th Ave NE Redmond WA 98052 USA Email: farooq.bari@att.com Rong Zhang China Telecom No.109 Zhongshandadao avenue Guangzhou 510630 China Email: zhangr@gsta.com Satoru Matsushima SoftBank Telecom 1-9-1 Higashi-Shinbashi, Munato-ku Tokyo Japan Email: satoru.matsushima@g.softbank.co.jp Shao, et al. Expires November 6, 2014 [Page 10]