July 2007 CAPWAP Protocol Specification Editors' Report July

July 2007 Editors’ Report Agenda 1.Highlights from -06/-03 issue resolution 2.Highlights from -07/-04 issue resolution 3.Discussion of new issues raised since publication of -07/-04 4.Next Steps

July 2007 Resolved Issues Issues Resolved in -06/-03 –248: Both IPv4 and IPv6 addresses not requiredBoth IPv4 and IPv6 addresses not required –250: Clarification onDTLSRehandshake/DTLSPeerAuthorize/DTLSIncomingSessionClarification onDTLSRehandshake/DTLSPeerAuthorize/DTLSIncomingSession –252: Heartbeat timer is undefinedHeartbeat timer is undefined –217: What is frame format when WTP encrypts/decryptsWhat is frame format when WTP encrypts/decrypts –249: UDP-Lite as optional transport for CAPWAPUDP-Lite as optional transport for CAPWAP –251: Retransmission of control packets is not exponentialRetransmission of control packets is not exponential Issues Resolved in -07/-04 –257: WTP IPvX addressWTP IPvX address –263: KeyLifetime should be removedKeyLifetime should be removed –262: Capwap state transition (Join to Image download)Capwap state transition (Join to Image download) –261: Issue with fix to issue 244 (Header Optimization)Issue with fix to issue 244 (Header Optimization) –254: Clarification required on use of UDP portsClarification required on use of UDP ports –258: DHCP Option Under-SpecifiedDHCP Option Under-Specified –244: preamble header optimizationpreamble 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 of the binding-02 draft did not specify which fields in the 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 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 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 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 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: DataChannelKeepAliveDataChannelKeepAlive –The text refers to this timer that was not defined in the spec Issue 16: MAC Address LengthMAC 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? –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