Subject: [Capwap] RE: Local MAC Tunneling Mode

From: "Pat Calhoun (pacalhou)" <[email-masked]>
Date: Wed, 18 Jan 2006 18:48:44 -0800

Saravanan,
 
Thanks for the contributed text. I have slightly changed the text you
proposed in order to allow a WTP to provide more than one mode of
operation and allow the AC to pick which mode it wants (based on some
internal policy).
 
The Discovery Request now includes: 

5.1.4.  WTP MAC Type

   The WTP MAC-Type message element allows the WTP to communicate its
   mode of operation to the AC.  A WTP that advertises support for both
   modes allows the AC to dictate the mode to use, based on some local
   policy decision.

      0                  
      0 1 2 3 4 5 6 7
     +-+-+-+-+-+-+-+-+
     |   MAC Type    |
     +-+-+-+-+-+-+-+-+

   Type:  TBD for WTP MAC Type

   Length:  1

   MAC Type:  The MAC mode of operation supported by the WTP.  The
      following values are supported

      0 - Local-MAC:  Local-MAC is the default mode that MUST be
         supported by all WTPs.

      1 - Split-MAC:  Split-MAC support is optional, and allows the AC
         to receive and process native wireless frames.

      2 - Both:  WTP is capable of supporting both Local-MAC and Split-
         MAC.

5.1.5.  WTP Frame Type

   The WTP Frame-Type message element allows the WTP to communicate its
   supported tunneling modes of operation to the AC.  A WTP that
   advertises support for all modes allows the AC to dictate which mode
   whill be used, based on its local policy.

      0              
      0 1 2 3 4 5 6 7
     +-+-+-+-+-+-+-+-+
     |   Frame Type  |
     +-+-+-+-+-+-+-+-+

   Type:  TBD for WTP Frame Type

   Length:  1

   Frame Type:  The Frame type specifies the encapsulation modes
      supported by the WTP.  The following values are supported

      0 - Local Briding:  Local Bridging allows the WTP to perform the
         bridging function.  Note this value MUST NOT be used when the
         MAC Type is set to Split-MAC.

      1 - 802.3 Bridging:  802.3 Bridging requires the WTP and AC to
         encapsulate all user payload as native 802.3 frames (see
         Section 4.2).  Note this value MUST NOT be used when the MAC
         Type is set to Split-MAC.

      2 - Native Bridging:  Native Bridging requires the WTP and AC to
         encapsulate all user payloads as native wireless frames, as
         defined by the wireless binding (see Section 4.2).

      3 - All:  The WTP is capable of supporting all frame types.

However, I have also allowed the message elements to be included in the
Join Response, allowing the AC to specify which modes it wants the WTP
to use. I have also included your proposed text under Configuration
Consistency, but it is less clear to me that this specific text is
mandatory, but would like to hear from others on whether they feel this
helps clarify the protocol.

Pat Calhoun
CTO, Wireless Networking Business Unit
Cisco Systems

________________________________

	From: Saravanan Govindan
[mailto:[email-masked]] 
	Sent: Thursday, December 22, 2005 8:43 PM
	To: Pat Calhoun (pacalhou); [email-masked]
	Subject: Local MAC Tunneling Mode

	Pat, 

	Thank you for summarizing the major recommendations. 
	
	The following is some proposed additions relating to the local
MAC tunneling mode recommendation. In essence, it adds identifiers for
the WTP variations and their modes of operation. I look forward to the
WG's review on this.

	Section: 5.1      Discover Request 

	Type of change: Additional text after 1st paragraph, ("The
Discovery Request is used by the WTP...")

	Proposal: 

	                        "The Discovery Request provides ACs with
primary functionalities of the WTP. A WTP must exchange this information
to ensure subsequent exchanges with the ACs are consistent with the
WTP's functional characteristics."

	            ------------------

	            Section: 5         LWAPP Discovery Operations 

	Type of change: Additional message elements

	Proposal-1:

	            "5.1.3               WTP MAC-Type

	The WTP MAC-Type message element distinguishes between local-MAC
and split-MAC WTPs. It is used by the AC to determine subsequent
exchanges with the WTP.

	Type: 

	Length: 1

	MAC-Type: An 8-bits value indicating the type of MAC used by the
WTP. 

	The following values are supported:

	0 - Split-MAC

	1 - Local-MAC"

	            Proposal-2:

	                        "5.1.4               WTP Frame Type

	The WTP Frame Type message element is used to determine the
nature of frames to be exchanged between the AC and WTP.

	Type: 

	Length: 1

	Frame Type: An 8-bits value indicating the type of frames to be
exchanged between the AC and WTP. 

	The following values are supported:

	0 - Native frames 

	1 - Tunneled frames (IEEE 802.3)

	2 - No frames (local bridge at WTP)"

	            ---------------------

	            Section: 7.1                  Configuration
Consistency 

	Type of change: Addition of sub-section to Section 7.1 

	Proposal: 

	            "7.1.1               Configuration Flexibility

	"The protocol also provides the flexibility to configure and
manage WTPs of varying design and functional characteristics. When a WTP
first discovers an AC, it provides primary functional information
relating to its type of MAC and to the nature of frames to be exchanged.
The AC configures the WTP appropriately. The AC also establishes
corresponding internal operations to deal with the WTP according to its
functionalities."

	            ----------------------

	It may be useful to use a figure to show how the modes are
selected and what happens afterwards. I can help prepare one if there is
agreement to do so.

	Saravanan 

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