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/.
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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.
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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
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| |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 |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 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 | |
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| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| |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] |
| |<------------------------------|
| | |
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| |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]
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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.
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[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
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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
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