STUN bis draft-ietf-behave-rfc3489bis Jonathan Rosenberg Cisco Systems

Changes from -04 to -05 Removed ICE connectivity check usage (in ICE now) FINGERPRINT optional –MUST use if cookie not enough –SHOULD use otherwise FINGERPRINT changed to CRC-32 (V.42 polynomial) FINGERPRINT attribute number to optional range TCP-based congestion control added in –Initial RTT estimate configurable, 100ms for fixed broadband –Retransmit interval doubles after every xmit (not flatten out) –Number of retransmits from 9 to 7 –Karns’ algorithm for RTT estimation mentioned

Changes from -04 to -05 New structure for Message Type –Bits M11 to M0 is “method” –C1 to C0 is “class” 0: Request 1: Indication 2: Success Response 3: Error Response Backwards compatible except TURN indications |M|M|M|M|M|C|M|M|M|C|M|M|M|M| |1|1|9|8|7|1|6|5|4|0|3|2|2|0| |1|0| | | | | | | | | | | | |

Changes from -04 to -05 Retransmission rules called out –Server sends same response –Client ignores subsequent responses Servers check for unknown methods and reject if unknown If you get a 436 when using short term credential from shared secret, reobtain Softened authentication rules on keepalive – discuss what to do if you don’t authenticate

Changes from -04 to -05 Clarify applicability of shared secrets (all servers or just one) Clarify behavior if request omitted MESSAGE- INTEGRITY but response has it Reuse short term credentials on 300 Clarify backwards compatibility for clients for XOR-MAPPED vs. MAPPED Server has to include MESSAGE-INTEGRITY in response if it was in request Success responses can include Nonce

Changes from -04 to -05 For shared secret requests, removed client IP address in computation of password –Leftover from rfc3489 stuff Added procedures for retry on timing out

Questions for the Group Happy with congestion control behavior? Happy with FINGERPRINT approach

Open Issues DNS Discovery –Not purely backwards compatible with RFC 3489 –Main difference _stun._tcp was for shared secret before, now for binding usage _stunpass._tcp for shared secret now, not defined previously –Recommendation: don’t care Otherwise, ready for WGLC