Transcript CAPWAP Protocol Specification Editors' Report July 2007

July 2007
CAPWAP Protocol
Specification Editors' Report
July 2007
[email protected]
[email protected]
[email protected]
July 2007
Editors’ Report Agenda
1.
2.
3.
4.
Highlights from -06/-03 issue resolution
Highlights from -07/-04 issue resolution
Discussion of new issues raised since publication of -07/-04
Next Steps
July 2007
Resolved Issues
• Issues Resolved in -06/-03
– 248: Both IPv4 and IPv6 addresses not required
– 250: Clarification
onDTLSRehandshake/DTLSPeerAuthorize/DTLSIncomingSession
– 252: Heartbeat timer is undefined
– 217: What is frame format when WTP encrypts/decrypts
– 249: UDP-Lite as optional transport for CAPWAP
– 251: Retransmission of control packets is not exponential
• Issues Resolved in -07/-04
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257: WTP IPvX address
263: KeyLifetime should be removed
262: Capwap state transition (Join to Image download)
261: Issue with fix to issue 244 (Header Optimization)
254: Clarification required on use of UDP ports
258: DHCP Option Under-Specified
244: preamble header optimization
July 2007
Issue Resolutions in -06, -03
• Issue 248 – Both IPv4 and IPv6 addresses not required
– Editorial problem. The text required the WTP to have *both* an IPv4
and an IPv6 address. The fix is that only one is now required.
• Issue 250 – Clarification on DTLSRehandshake
/DTLSPeerAuthorize / DTLSIncomingSession
– There were three problems that existed with the DTLS text.
Specifically:
1. The DTLSRehandshake timer still existed in the spec, but
rehandshake is not supported by CAPWAP.
2. The state machine pointed to the DTLSPeerAuthorize notification,
which was not specified in the document.
3. DTLSIncomingSession notification existed, but the state machine
did not refer to it. The state machine included the actual state change,
but was missing the text to point to the notification.
July 2007
Issue Resolutions in -06, -03
• Issue 252 – Heartbeat timer is undefined
– The text made references to a “Heartbeat timer”,
but the actual timer is called the EchoInterval
timer.
• Issue 217 – What is frame format when
WTP encrypts / decrypts
– Section 2.1.1 of the binding-02 draft did not
specify which fields in the 802.11 header the WTP
and AC were responsible for setting when
encryption occurred in the WTP.
July 2007
Issue Resolutions in -06, -03
• Issue 249 – UDP-Lite as optional transport for
CAPWAP
– In order for hardware to be able to process UDP headers
efficiently, the spec calls for a zero (0) checksum. However,
IPv6 does not allow zero (0) checksum with UDP, which
caused the WG to adopt UDP-Lite when CAPWAP is run
over IPv6.
• Issue 251 – Retransmission of control packets is
not exponential
– The CAPWAP protocol did not have any congestion control
mechanisms, which we knew would be a problem during
the IESG review. The control protocol now has exponential
backoff.
July 2007
Issue Resolutions in -07, -04
• Issue 257 - WTP IPvX address
– The CAPWAP protocol states that the WTP IPv4 Address
message element can be used to determine if NAT is performed.
However, there is no similar IPv6 message element. This was
added in order to support v4< - >v6 scenarios.
• Issue 263 - KeyLifetime should be removed
– The Working Group had agreed we would not use DTLS
rekeying, but the KeyLifetime field was never removed from the
spec.
• Issue 262 - Capwap state transition (Join to Image
download)
– When the WTP entered the Image Data state (for image
downloads), it would not initialize the Echo Request timer.
July 2007
Issue Resolutions in -07, -04
• Issue 261 – Issue with fix to issue 244 (Header
Optimization)
– The introduction of issue 244 (Header Optimization) created editorial
issues.
• Issue 254 – Clarification required on use of UDP ports
– The specification made references to control channel, control ports,
control plane, etc. The same was true for the data channel. This issue
ensured that the spec used a common terminology throughout, and
added definitions for both the control and data channel.
• Issue 258 – DHCP Option Under-Specified
– The use of DHCP in the CAPWAP specification was inconsistent with
how DHCP options are defined. The text was removed and moved to a
separate specification that follows DHCP protocol conventions.
• Issue 244 - preamble header optimization
– The issue raised was that the CAPWAP headers could be optimized to
reduce the overhead and duplication of fields.
July 2007
Issues Being Addressed for -08/-05
• Issue 15: DataChannelKeepAlive
– The text refers to this timer that was not defined in
the spec
• Issue 16: MAC Address Length
– The text included a MAC Address field of 9 bytes
(instead of 8) in various message elements.
July 2007
Next Steps
•
Plan is to submit -08/-05 after IETF meeting
–
Depends largely on whether transport issues need to be
addressed
Need some guidance on which issues are show stoppers
–
•
Do the chair anticipate another WG Last Call?
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–
Since the WG Last Call occurred on -06/-03, some
technical changes were introduced that may warrant
another one.
Do we need another IEEE review? No comments were
received on the previous version