Section A Table of Timer Values

Table 4 summarizes the meaning and defaults of the various timers
   used by this specification.
Timer    Value            Section               Meaning
----------------------------------------------------------------------
T1       500ms default    Section 17.1.1.1     RTT Estimate
T2       4s               Section 17.1.2.2     The maximum retransmit
                                               interval for non-INVITE
                                               requests and INVITE
                                               responses
T4       5s               Section 17.1.2.2     Maximum duration a
                                               message will
                                               remain in the network
Timer A  initially T1     Section 17.1.1.2     INVITE request retransmit
                                               interval, for UDP only
Timer B  64*T1            Section 17.1.1.2     INVITE transaction
                                               timeout timer
Timer C  > 3min           Section 16.6         proxy INVITE transaction
                           bullet 11            timeout
Timer D  > 32s for UDP    Section 17.1.1.2     Wait time for response
         0s for TCP/SCTP                       retransmits
Timer E  initially T1     Section 17.1.2.2     non-INVITE request
                                               retransmit interval,
                                               UDP only
Timer F  64*T1            Section 17.1.2.2     non-INVITE transaction
                                               timeout timer
Timer G  initially T1     Section 17.2.1       INVITE response
                                               retransmit interval
Timer H  64*T1            Section 17.2.1       Wait time for
                                               ACK receipt
Timer I  T4 for UDP       Section 17.2.1       Wait time for
         0s for TCP/SCTP                       ACK retransmits
Timer J  64*T1 for UDP    Section 17.2.2       Wait time for
         0s for TCP/SCTP                       non-INVITE request
                                               retransmits
Timer K  T4 for UDP       Section 17.1.2.2     Wait time for
         0s for TCP/SCTP                       response retransmits
                   Table 4: Summary of timers
Acknowledgments
   We wish to thank the members of the IETF MMUSIC and SIP WGs for their
   comments and suggestions.  Detailed comments were provided by Ofir
   Arkin, Brian Bidulock, Jim Buller, Neil Deason, Dave Devanathan,
   Keith Drage, Bill Fenner, Cedric Fluckiger, Yaron Goland, John
   Hearty, Bernie Hoeneisen, Jo Hornsby, Phil Hoffer, Christian Huitema,
   Hisham Khartabil, Jean Jervis, Gadi Karmi, Peter Kjellerstedt, Anders
   Kristensen, Jonathan Lennox, Gethin Liddell, Allison Mankin, William
   Marshall, Rohan Mahy, Keith Moore, Vern Paxson, Bob Penfield, Moshe
   J. Sambol, Chip Sharp, Igor Slepchin, Eric Tremblay, and Rick
   Workman.
   Brian Rosen provided the compiled BNF.
   Jean Mahoney provided technical writing assistance.
   This work is based, inter alia, on [41,42].
Authors' Addresses
   Authors addresses are listed alphabetically for the editors, the
   writers, and then the original authors of RFC 2543.  All listed
   authors actively contributed large amounts of text to this document.
   Jonathan Rosenberg
   dynamicsoft
   72 Eagle Rock Ave
   East Hanover, NJ 07936
   USA
   EMail:  jdrosen@dynamicsoft.com
   Henning Schulzrinne
   Dept. of Computer Science
   Columbia University
   1214 Amsterdam Avenue
   New York, NY 10027
   USA
   EMail:  schulzrinne@cs.columbia.edu
   Gonzalo Camarillo
   Ericsson
   Advanced Signalling Research Lab.
   FIN-02420 Jorvas
   Finland
   EMail:  Gonzalo.Camarillo@ericsson.com
   Alan Johnston
   WorldCom
   100 South 4th Street
   St. Louis, MO 63102
   USA
   EMail:  alan.johnston@wcom.com
   Jon Peterson
   NeuStar, Inc
   1800 Sutter Street, Suite 570
   Concord, CA 94520
   USA
   EMail:  jon.peterson@neustar.com
   Robert Sparks
   dynamicsoft, Inc.
   5100 Tennyson Parkway
   Suite 1200
   Plano, Texas 75024
   USA
   EMail:  rsparks@dynamicsoft.com
   Mark Handley
   International Computer Science Institute
   1947 Center St, Suite 600
   Berkeley, CA 94704
   USA
   EMail:  mjh@icir.org
   Eve Schooler
   AT&T Labs-Research
   75 Willow Road
   Menlo Park, CA 94025
   USA
   EMail: schooler@research.att.com