Subject: Re: [Capwap] Proposed Text for Issue 254

From: "Abhijit Choudhury (achoudhu)" <[email-masked]>
Date: Wed, 4 Apr 2007 12:57:13 -0700

While trying to address Issue 254, I realized that there are a number of
places in the CAPWAP protocol spec that we need to fix.
I also noticed that in the spec, we start using "data channel"
and "control channel" without defining what they are.
 
I propose the following changes:
 
1. Add the following to Terminology (Section 1.4)
 
      CAPWAP Control Channel:  A connection defined by (WTP-IP-Addr,
AC-IP-Addr, 
        WTP-Control-Layer4Port, AC-Control-Layer4Port) over which CAPWAP
control  
        packets are sent.
 
        CAPWAP Data Channel:  A connection defined by (WTP-IP-Addr,
AC-IP-Addr, 
        WTP-Data-Layer4Port, AC-Data-Layer4Port) over which CAPWAP data
packets 
        are sent.

2. In Section 3.1
    Replace

        CAPWAP protocol control packets sent between the WTP and the AC
use
        well known UDP port [to be IANA assigned].  CAPWAP protocol data
        packets sent between the WTP and the AC use UDP port [to be IANA
        assigned].

    With
         CAPWAP protocol control packets sent from the WTP to the AC use
         well known UDP port [to be IANA assigned] at the AC and any
         port selected by the implementation at the WTP. CAPWAP protocol
data
         packets sent from the WTP to the AC use UDP port [to be IANA
         assigned] at the AC and any port selected by the implementation

         at the WTP. In either case, for packets sent by the AC to the
WTP, 
         the source and destination ports are reversed.

3. In Section 4.1
    Replace
         Payload Type:  A 4 bit field which specifies the payload type
that
          follows the preamble header.  The following values are
supported:
 
          0 -  Clear text.  If the packet is received on the data UDP
port,
             the CAPWAP stack MUST treat the packet as a clear text
CAPWAP
             data packet.  If received on the control UDP port, the
CAPWAP
             stack MUST treat the packet as a clear text CAPWAP control
             packet.  If the control packet is not a Discovery Request
or
             Response packet, the packet MUST be dropped.
 
          1 -  DTLS Payload.  The packet is a DTLS packet and MAY be a
data
             or control packet, based on the UDP port it was received on
             (see Section 3.1).
 
    With
         Payload Type:  A 4 bit field which specifies the payload type
that
          follows the preamble header.  The following values are
supported:
 
          0 -  Clear text.  If the packet is received on the CAPWAP data
channel,
             the CAPWAP stack MUST treat the packet as a clear text
CAPWAP
             data packet.  If received on the CAPWAP control channel,
the CAPWAP
             stack MUST treat the packet as a clear text CAPWAP control
             packet.  If the control packet is not a Discovery Request
or
             Response packet, the packet MUST be dropped.
 
          1 -  DTLS Payload.  The packet is a DTLS packet and MAY be a
data
             or control packet, based on the channel it was received on
             (see Section 3.1).

4. In Section 4.3
   Replace
      Both CAPWAP data messages are transmitted on the data channel UDP
port.
   With
       Both CAPWAP data messages are transmitted on the data channel.

Thanks,
Abhijit

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---

From: "Abhijit Choudhury (achoudhu)" <[email-masked]>
Date: Wed, 4 Apr 2007 13:24:15 -0700

Typo in text below. Should read:

      CAPWAP Control Channel:  A connection defined by (WTP-IP-Addr,
AC-IP-Addr, 
        IP Protocol, WTP-Control-Layer4Port, AC-Control-Layer4Port) over
which 
        CAPWAP control packets are sent.
 
        CAPWAP Data Channel:  A connection defined by (WTP-IP-Addr,
AC-IP-Addr, 
        IP Protocol, WTP-Data-Layer4Port, AC-Data-Layer4Port) over which

        CAPWAP data packets are sent.

Thanks,
Abhijit

________________________________

From: Abhijit Choudhury (achoudhu) 
Sent: Wednesday, April 04, 2007 12:57 PM
To: capwap; Pat Calhoun (pacalhou); Puneet Agarwal
Subject: Re: [Capwap] Proposed Text for Issue 254

 

2. In Section 3.1
    Replace

    With

3. In Section 4.1
    Replace

 
    With

4. In Section 4.3
   Replace

Thanks,
Abhijit