Network Working Group C. Shao Internet-Draft H. Deng Intended status: Standards Track China Mobile Expires:April 14,August 18, 2014 R. Pazhyannur Cisco F. Bari AT&T R. Zhang China Telecom S. Matsushima SoftBank TelecomOctober 11, 2013February 14, 2014 IEEE 802.11 MAC Profile for CAPWAPdraft-ietf-opsawg-capwap-hybridmac-01draft-ietf-opsawg-capwap-hybridmac-02 AbstractTheCAPWAPprotocoldefines two entities Wireless Transmission Point (WTP) and Access Controller (AC). CAPWAP also defines two MAC (Medium Access Control) modesof operationfor IEEE 802.11 WTPs: Split and Local MAC(medium access control), as described in [RFC5415],[RFC5416]. Specifically, [RFC5416]. For each MAC mode, CAPWAP describesin detailhow thedivision of laborMAC functionality is split betweenWTP and AC intheSplitWTP andLocal MAC modes. Unfortunately, there are manyAC. However, certain functionsthathave notyetbeen clearlydefined whether they belong to the WTP or the AC.defined. For example for the Split MAC mode, the IEEE 802.11 encryption is specified as located in eitherinthe AC or the WTP with no clear way for the AC tonegotiateinform the WTP where it shouldbe located.be. This lack of specification leads to interoperabilitybetween AC and WTPespecially when AC and WTP come from different vendors. To solvethisthe problem, this specification definesthe concept ofa IEEE 802.11 MAC profile where each profilerefers to a table containingspecifies an unambigous division oflaborfunctionality between the WTP and AC. The IEEE 802.11 MAC profile is used as follows:theThe WTP informs the AC of the supported profiles during the discovery or join process and the ACselects the profile when itconfigures theWTP.WTP with one of the supported profiles while configuring a 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 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 onApril 14,August 18, 2014. Copyright Notice Copyright (c)20132014 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 MACProfile . . . . . .with WTP encryption . . . . . . . . . . . . . . 4 3.2.LocalSplit MACProfile . . . . . .with AC encryption . . . . . . . . . . . . . . 5 3.3.HybridIEEE 802.11 MAC Profile Frame Exchange . . . . . . . . . 6 4. MAC Profile Message Element Definitions . . . . . . . . . . .6 3.3.1. Hybrid-MAC model Frames Exchange7 4.1. IEEE 802.11 Supported MAC Profiles . . . . . . . . . . . 74.4.2. IEEE 802.11 MAC Profile . . . . . . . . . . . . . . . . .. .8 5. Security Considerations . . . . . . . . . . . . . . . . . . . 8 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . .98 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 9 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 9. Normative References . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . .109 1. Introduction The CAPWAP protocol supports two MAC modes of operation: Split and Local MAC,which has beenas 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,[RFC5415], [RFC5416]. However, there aremanyMAC functions that have notyetbeen clearlydefined whether they belong to either the WTP or the AC in the Split and Local modes.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, the operators in their deployments have to perform different configurations based on implementation of the two modes by their vendor. If there is no cleardefinition of split MAC and local MAC,specification then operators willcontinue toexperience 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 SplitMAC. 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. ThereforeMAC mode. Specifically, note that in thelocation of these features becomes vendor specific and this increasesSplit MAC mode thedifficulty of interoperability between WTPs and ACs from different vendors.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 | WTP | AC | + (WPA2) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.11 | WTP | WTP/AC | + |Encryption/Decryption | | | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: Functions in Local MAC and Split MAC Toallievate the above mentionedsolve this problem, this specification introduces IEEE 802.11 MAC profle. The MAC profile unamabigously specifies where the various MACfucntionaityfucntionality 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 ofa fucntionalhow the MAC functionality is split between the WTP and ACsshown in Figure 1 3.1. Split MACProfilewith WTP encryption The functional split for the Split MACprofilewith WTP encryption is provided in Figure 2.The Split MACThis profile isidenticalsimilar to the Split MACmode definedexcept 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[RFC5416]. Description of various fucntionalitythis profile fragmentation/ defragmentation is also done only at the WTP Note that scheduling functionality isavailabledenoted as WTP/AC. As explained inSection 2.2.1[RFC5416], this means that the admission control component of[RFC5416].IEEE 802.11 resides on the AC, the real-time scheduling and queuing functions are on the WTP. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Functions |Split MACProfile | | | 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Distribution Service | AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Integration Service | AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Beacon Generation | WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Probe Response Generation| WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Function |Power Mgmt | WTP | + |/Packet Buffering | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Fragmentation |WTP/ACWTP | + |/Defragmentation | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Assoc/Disassoc/Reassoc | AC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Classifying | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 QoS |Scheduling | WTP/AC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Queuing | WTP | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE802.1X/EAP802.1X/EWTP | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 RSN |RSNA Key Management | AC | + (WPA2) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.11 |WTP/ACWTP | + |Encryption/Decryption | | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: Functions in Split MAC with WTP Encryption 3.2.LocalSplit MACProfilewith AC encryption The functional split for theLocalSplit MACprofilewith AC encryption is provided in Figure 3.The local MACThis profile isidenticalsimilar to theLocalSplit MACmode defined in [RFC5416]. Description of various fucntionalityexcept that IEEE 802.11 encryption/decryption is done only at the AC. Since fragmentation isavailablealways done at the same entity as the encryption, inSection 2.2.2 of [RFC5416].this rofile, AC does fragmentation/defragmentation. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Functions |Local MACProfile | | | 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Distribution Service |WTP/ACAC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Integration Service |WTPAC | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Beacon Generation | WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Probe Response Generation| WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Function |Power Mgmt | WTP | + |/Packet Buffering | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Fragmentation |WTPAC | + |/Defragmentation | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Assoc/Disassoc/Reassoc |WTP/ACAC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Classifying |WTPAC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 QoS |Scheduling | WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Queuing | WTP | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE802.1X/EAP802.1X/EWTP | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 RSN |RSNA Key Management | AC | + (WPA2) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.11 |WTPAC | + |Encryption/Decryption | | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: Functions inLocalSplit MAC with AC encryption 3.3.HybridIEEE 802.11 MAC ProfileThe functional split forFrame Exchange An example of message exchange using theHybridthe IEEE 802.11 MACprofileProfile message element isprovidedshown in Figure 4. TheHybrid MAC is similar to the Split MAC except that scheduling is done only at the WTP, and IEEE 802.11 encryption/decryption is done atWTP informs theWTP. Note thatAC of theSplitvarious MACprofile allowed encryption to beprofiles it supports. This happens eitherat the WTPin a Discovery Request message or theAC. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Classifying | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 QoS |Scheduling | WTP | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |Queuing | WTP | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.1X/EWTP | AC | + IEEE +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 RSN |RSNA Key Management |Join Request message. The AC| + (WPA2) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |IEEE 802.11 |determines the appropriate profile and the configures the WTP| + |Encryption/Decryption | | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4: Functions in Hybrid MAC 3.3.1. Hybrid-MAC model Frames Exchange An example of frame exchange usingwith theproposed Hybrid-MAC Model shown in Figure 5.profile while configuring the WLAN. +-+-+-+-+-+-++-+-+-+-+-++-+-+-+-+-+-+ |STA | |WTP | | AC | +-+-+-+-+-+-++-+-+-+-+-++-+-+-+-+-+-+| | | | Beacon | | |<-------------------------| | | Probe | | |<------------------------>| | | 802.11 AUTH/Association | |<-------------------------------------------------------->| | |Station Configuration Request [| | Add Station (Station MAC Address),| | IEEE 802.11 Add Station (WLAN ID),| ||Join Request[Supported IEEE 802.11Session Key(Flag=A)]| ||<------------------------------| |MAC Profiles ] | |---------------------------------------->| | ||Station Configuration|Join Response | |<----------------------------------------| ||------------------------------>||802.1X Authentication &|IEEE 802.11Key Exchange | |<-------------------------------------------------------->| | |Station ConfigurationWLAN Config. Request[|[ |Add Station (Station MAC Address),|| IEEE 802.11 AddStation (WLAN ID),| | IEEE 802.11 Station Session Key]WLAN, | ||<------------------------------| | | | | |Station Configuration Response | | |------------------------------>| |IEEE 802.11Action FramesMAC Profile ||<-------------------------------------------------------->||DATA Frame Exchange] | |<----------------------------------------| |802.11 Data| |IEEE 802.11or 802.3 DataWLAN Config. Response ||<-------------------------+------------------------------>||---------------------------------------->| Figure5: Hybrid-MAC model Frames4: Message Exchange For Negotiating MAC Profile 4. MAC Profile Message Element Definitions 4.1. IEEE 802.11 Supported MACProfileProfiles The IEEE 802.11WTPSupported MAC Profile message element allows the WTP to communicate theprofileprofiles itsupports to the AC.supports. The Discovery Request message, Primary Discovery Request message, and Join Request message may include one such messageelementelement. 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].. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- Figure6:5: IEEE 802.11 Supported MACProfileProfiles o Type: TBD for IEEE 802.11 Supported MACProfileProfiles o Num_Profiles >=1: This refers to number of profilespresntpresent in this messaage element. There must be at least one profile. o Profile: Each profile is idnentified by a value specified in Section 4.2. 4.2. IEEE 802.11 MAC Profile The IEEE 802.11 MAC Profile message element allows the AC to select a profile. This messsage 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 theLocalSplit MAC Profiledescribed in Section 3.2with WTP encryption * 1: This refers to the Split MAC Profiledescribed in Section 3.1 * 2: This refers to the Hybrid MAC Profile described in Section 3.3with AC encryption 5. Security Considerations This document doesn't specify security risk difference from [RFC5416].It could directlyPlease refer to the Security section of [RFC5416] 6. IANA Considerations This document requires the following IANA actions. o This specification defines a new message element, IEEE 802.11 Supported MACProfile.Profiles. The format of this option is described in Section3.3. Type4.1. This valuefor this optionneeds to beassigned from the same numbering space as allocated forregsitered in theotherexisting CAPWAP Message Element Type registry, defined in [RFC5415]. o This specification defines a new message element, IEEE 802.11message elements as definedMAC Profile. The format of this option is described in[RFC5416]Section 4.2. This value needs to be regsitered in the existing CAPWAPIEEE 802.11MessageTypes sub-registryElement Type registry, defined in [RFC5415]. o The Profile field in the IEEE 802.11 Supported MAC Profiles message element and IEEE 802.11 MAC ProfileTypemessage element (seeFigure 6) The namespaceSection 4.2) is8 bits (0-255), whereused to denote thevalue ofMAC profile. This document defines two values, zero (0)through two (2)and one (1), and the remaining values (2-255) areallocated in this specification,controlled andcan be found in Figure 6. This namespace is managedmaintained by IANA andassignmentsrequire an ExpertReview under the registry IEEE 802.11 MAC Profile for CAPWAPReview. 7. Contributors Yifan Chen chenyifan@chinamobile.com Naibao Zhou zhounaibao@chinamobile.com 8. Acknowledgments Theauthor thanks the kind advicesauthors are grateful for extremely valuable suggestions from Dorothy Stanley inthe development ofdeveloping thisdocument. The efforts of Margaret Wasserman, Wes George in reviewing this document are gratefully acknowledged.specification. Guidance from management team: Melinda Shore, Scott Bradner, Chris Liljenstolpe, Benoit Claise, Joel Jaeggli,RomascanuDan 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. [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. [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 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