Network Working Group C. Shao Internet-Draft H. Deng Intended status: Standards Track China Mobile Expires: April 14, 2014 R. Pazhyannur Cisco F. Bari AT&T R. Zhang China Telecom S. Matsushima SoftBank Telecom October 11, 2013 IEEE 802.11 MAC Profile for CAPWAP draft-ietf-opsawg-capwap-hybridmac-01 Abstract The CAPWAP protocol defines two modes of operation for IEEE 802.11 WTPs: Split and Local MAC (medium access control), as described in [RFC5415],[RFC5416]. Specifically, [RFC5416] describes in detail the division of labor between WTP and AC in the Split and Local MAC modes. Unfortunately, there are many functions that have not yet been clearly defined whether they belong to the WTP or the AC. 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. This lack of specification leads to interoperability between AC and WTP when AC and WTP come from different vendors. To solve this problem, this specification defines the concept of IEEE 802.11 MAC profile where each profile refers to a table containing an unambigous division of labor between WTP and AC. The profile is used as follows: the WTP informs the AC of the supported profiles and the AC selects the profile when it configures the WTP. 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/. Shao, et al. Expires April 14, 2014 [Page 1] Internet-Draft CAPWAP October 2013 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 April 14, 2014. Copyright Notice Copyright (c) 2013 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 Profile . . . . . . . . . . . . . . . . . . . . 4 3.2. Local MAC Profile . . . . . . . . . . . . . . . . . . . . 5 3.3. Hybrid MAC Profile . . . . . . . . . . . . . . . . . . . 6 3.3.1. Hybrid-MAC model Frames Exchange . . . . . . . . . . 7 4. IEEE 802.11 MAC Profile . . . . . . . . . . . . . . . . . . . 8 5. Security Considerations . . . . . . . . . . . . . . . . . . . 8 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 9 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 9. Normative References . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction The CAPWAP protocol supports two MAC modes of operation: Split and Local MAC, which has been described in [RFC5415][RFC5416]. In Split MAC mode, all L2 wireless data and management frames are encapsulated via the CAPWAP protocol and exchanged between the AC and the WTP. The Local MAC mode of operation allows for the data frames to be either locally bridged or tunneled as 802.3 frames. Unfortunately, there are many functions that have not yet been clearly defined Shao, et al. Expires April 14, 2014 [Page 2] Internet-Draft CAPWAP October 2013 whether they belong to either the WTP or the AC in the Split and Local modes. 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, 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 definition of split MAC and local MAC, then operators will continue to experience difficulty in interoperating WTPs and ACs from different vendors. Figure 1 quoted from [RFC5416], illustrates how the functions are processed in different places in the Local MAC and Split MAC. Further, for some functions such as the Frag. / Defrag. Assoc. / Disassoc / Reassoc., Encryption the protocol does not explicitly map processing of such functions to the WTP or the AC. Therefore the location of these features becomes vendor specific and this increases the difficulty of interoperability between WTPs and ACs from different vendors. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Shao, et al. Expires April 14, 2014 [Page 3] Internet-Draft CAPWAP October 2013 | |IEEE 802.1X/EWTP | AC | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 RSN |RSNA Key Management | WTP | AC | + (WPA2) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.11 | WTP | WTP/AC | + |Encryption/Decryption | | | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: Functions in Local MAC and Split MAC To allievate the above mentioned problem, this specification introduces IEEE MAC profle. The MAC profile unamabigously specifies where the various MAC fucntionaity should be located. Further we define different MAC profiles based on currently known MAC implementations. The WTP may support one or more pfofiles and will indicate the supported profiles to the AC. The AC will select a profile and configure it the WTP. 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 a fucntional split between the WTP and AC s shown in Figure 1 3.1. Split MAC Profile The functional split for the Split MAC profile is provided in Figure 2. The Split MAC profile is identical to the Split MAC mode defined in [RFC5416]. Description of various fucntionality is available in Section 2.2.1 of [RFC5416]. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Functions | Split MAC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Distribution Service | AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Integration Service | AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Beacon Generation | WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Probe Response Generation| WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Shao, et al. Expires April 14, 2014 [Page 4] Internet-Draft CAPWAP October 2013 | Function |Power Mgmt | WTP | + |/Packet Buffering | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Fragmentation | WTP/AC | + |/Defragmentation | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Assoc/Disassoc/Reassoc | AC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Classifying | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 QoS |Scheduling | WTP/AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Queuing | WTP | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.1X/EAP | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 RSN |RSNA Key Management | AC | + (WPA2) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.11 | WTP/AC | + |Encryption/Decryption | | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: Functions in Split MAC 3.2. Local MAC Profile The functional split for the Local MAC profile is provided in Figure 3. The local MAC profile is identical to the Local MAC mode defined in [RFC5416]. Description of various fucntionality is available in Section 2.2.2 of [RFC5416]. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Functions | Local MAC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Distribution Service | WTP/AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Integration Service | WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Beacon Generation | WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Probe Response Generation| WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Function |Power Mgmt | WTP | + |/Packet Buffering | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Fragmentation | WTP | + |/Defragmentation | | Shao, et al. Expires April 14, 2014 [Page 5] Internet-Draft CAPWAP October 2013 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Assoc/Disassoc/Reassoc | WTP/AC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Classifying | WTP | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 QoS |Scheduling | WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Queuing | WTP | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.1X/EAP | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 RSN |RSNA Key Management | AC | + (WPA2) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.11 | WTP | + |Encryption/Decryption | | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: Functions in Local MAC 3.3. Hybrid MAC Profile The functional split for the Hybrid MAC profile is provided in Figure 4. The Hybrid MAC is similar to the Split MAC except that scheduling is done only at the WTP, and IEEE 802.11 encryption/decryption is done at the WTP. Note that the Split MAC profile allowed encryption to be either at the WTP or the AC. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Functions | Hybrid MAC| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Shao, et al. Expires April 14, 2014 [Page 6] Internet-Draft CAPWAP October 2013 | |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 | WTP | + |Encryption/Decryption | | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4: Functions in Hybrid MAC 3.3.1. Hybrid-MAC model Frames Exchange An example of frame exchange using the proposed Hybrid-MAC Model shown in Figure 5. +-+-+-+-+-+-+ +-+-+-+-+-+ +-+-+-+-+-+-+ | STA | | WTP | | AC | +-+-+-+-+-+-+ +-+-+-+-+-+ +-+-+-+-+-+-+ | | | | Beacon | | |<-------------------------| | | Probe | | |<------------------------>| | | 802.11 AUTH/Association | |<-------------------------------------------------------->| | |Station Configuration Request [| | Add Station (Station MAC Address),| | IEEE 802.11 Add Station (WLAN ID),| | IEEE 802.11 Session Key(Flag=A)] | | |<------------------------------| | | | | |Station Configuration Response | | |------------------------------>| | 802.1X Authentication & 802.11 Key Exchange | |<-------------------------------------------------------->| | |Station Configuration Request [| | Add Station (Station MAC Address),| | IEEE 802.11 Add Station (WLAN ID),| | IEEE 802.11 Station Session Key] | | |<------------------------------| | | | Shao, et al. Expires April 14, 2014 [Page 7] Internet-Draft CAPWAP October 2013 | |Station Configuration Response | | |------------------------------>| | 802.11 Action Frames | |<-------------------------------------------------------->| | DATA Frame Exchange | | 802.11 Data | 802.11 or 802.3 Data | |<-------------------------+------------------------------>| Figure 5: Hybrid-MAC model Frames Exchange 4. IEEE 802.11 MAC Profile The IEEE 802.11 WTP Profile message element allows the WTP to communicate the profile it supports to the AC. 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 6: IEEE 802.11 MAC Profile o Type: TBD for IEEE 802.11 MAC Profile o Num_Profiles >=1: This refers to number of profiles presnt in this messaage element. There must be at least one profile. o Profile: Each profile is idnentified by a value as given below * 0: This refers to the Local MAC Profile described in Section 3.2 * 1: This refers to the Split MAC Profile described in Section 3.1 * 2: This refers to the Hybrid MAC Profile described in Section 3.3 5. Security Considerations This document doesn't specify security risk difference from [RFC5416]. It could directly refer to Security section of [RFC5416] Shao, et al. Expires April 14, 2014 [Page 8] Internet-Draft CAPWAP October 2013 6. IANA Considerations This document requires the following IANA actions. o This specification defines a new message element, IEEE 802.11 MAC Profile. The format of this option is described in Section 3.3. Type value for this option needs to be assigned from the same numbering space as allocated for the other IEEE 802.11 message elements as defined in [RFC5416] in the CAPWAP IEEE 802.11 Message Types sub-registry o The Profile field in the IEEE 802.11 MAC Profile Type message element (see Figure 6) The namespace is 8 bits (0-255), where the value of zero (0) through two (2) are allocated in this specification, and can be found in Figure 6. This namespace is managed by IANA and assignments require an Expert Review under the registry IEEE 802.11 MAC Profile for CAPWAP 7. Contributors Yifan Chen chenyifan@chinamobile.com Naibao Zhou zhounaibao@chinamobile.com 8. Acknowledgments The author thanks the kind advices from Dorothy Stanley in the development of this document. The efforts of Margaret Wasserman, Wes George in reviewing this document are gratefully acknowledged. Guidance from management team: Melinda Shore, Scott Bradner, Chris Liljenstolpe, Benoit Claise, Joel Jaeggli, Romascanu Dan 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. [RFC4564] Govindan, S., Cheng, H., Yao, ZH., Zhou, WH., and L. Yang, "Objectives for Control and Provisioning of Wireless Access Points (CAPWAP)", RFC 4564, July 2006. [RFC5415] Calhoun, P., Montemurro, M., and D. Stanley, "Control And Provisioning of Wireless Access Points (CAPWAP) Protocol Specification", RFC 5415, March 2009. Shao, et al. Expires April 14, 2014 [Page 9] Internet-Draft CAPWAP October 2013 [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 Rajesh S. Pazhyannur Cisco 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 Shao, et al. Expires April 14, 2014 [Page 10] Internet-Draft CAPWAP October 2013 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 April 14, 2014 [Page 11]