rfc3105.txt

RFC 的详细文档！

      collects all the returned service URLs.

   2. For each service URL, the client performs an SLP attribute request
      for the attribute LOAD.  The integer load figures are returned.

   3. The client sorts through the returned load figures and selects the
      URL having the least number of connections.  The client
      establishes its RSIP session with that server.

   Because of network delays, this procedure does not guarantee that a
   client will always obtain a connection with the lightest loaded
   server, but it does provide a high probability that the selected
   server is more lightly loaded.

   A similar procedure is used in [9] to load balance access to TN3270E
   telnet servers.











Kempf & Montenegro            Experimental                      [Page 6]

RFC 3105            Finding an RSIP Server with SLP         October 2001


7.  The RSIP Service Type Template

   Name of submitters: James Kempf <[e-mail]>
                       Gabriel Montenegro <[e-mail]>

   Language of service template: en

   Security Considerations:
      RSIP clients can use Service Location Protocol to find RSIP
      servers having particular security characteristics.  If secure
      access to such information is required, SLP security should be
      used.







































Kempf & Montenegro            Experimental                      [Page 7]

RFC 3105            Finding an RSIP Server with SLP         October 2001


Template text:
----------------------template begins here -------------------------
template-type = rsip

template-version = 0.0

template-description=
   The service:rsip type provides advertisements for clients seeing
   realm-specific IP (RSIP) servers.  RSIP servers use the Realm
   Specific IP protocol to manage addresses and other resources
   from one realm on behalf of a client in another realm.

template-url-syntax=
   ;No additional URL path information required.  An example service
   ;URL for an RSIP server is: service:rsip://gateway.mydomain:4455

ipsec-support = BOOLEAN O
   #True if the server supports IPSEC as per [10]

ike-support = BOOLEAN O
   #True if the server supports IKE as per [10]

tunnel-type = STRING L M O
IP-IP
   #The tunneling methods supported by the RSIP server.  Clients
   #should include this attribute in a query so that they obtain a
   #server offering a tunneling method for which they have
   #support.  Default is IP-IP.  The values are currently
   #restricted to IP-IP, L2TP, GRE and NONE.  A server can support
   #multiple tunnel types.
IP-IP,L2TP,GRE,NONE

transport = STRING L M O
TCP
   #Transport used by the RSIP protocol itself.
TCP,UDP

load = INTEGER O
   #If the server supports load balancing, this attribute should be
   #set to an integer from 0 to 100.  0 is the lowest indication of
   #load and 100 the highest.  Clients can query for this attribute
   #and obtain load information, from which they can make an
   #intelligent decision about which server to use.
----------------------template ends here ---------------------------







Kempf & Montenegro            Experimental                      [Page 8]

RFC 3105            Finding an RSIP Server with SLP         October 2001


8.  Security Considerations

   Service type templates provide information that is used to interpret
   information obtained by clients through SLP.  If the RSIP template is
   modified or if a false template is distributed, RSIP servers may not
   correctly register themselves, or RSIP clients may not be able to
   interpret service information.

   SLP provides an authentication mechanism for UAs to assure that
   service advertisements only come from trusted SAs [2].  If trust is
   an issue, particularly with respect to the information sought by the
   client about IPSEC and IKE support, then SLP authentication should be
   enabled in the network.

9.  Summary

   This document describes how SLP can be used by RSIP clients to find
   RSIP servers.  A service type template for an RSIP SLP service type
   is presented.  In addition, a few techniques for provisioning access
   to service advertisements for particular gateway servers, and for
   load balancing using SLP were provided.  The result should allow RSIP
   service provisioning that is considerably more dynamic and robust
   than when traditional service discovery mechanisms are used.

References

   [1]  Borella, M., Grabelsky, D., Lo, J. and K. Taniguchi, "Realm
        Specific IP: Protocol Specification", RFC 3103, April 2001.

   [2]  Guttman, E., Perkins, C., Veizades, J. and M. Day, "Service
        Location Protocol, version 2", RFC 2608, July 1999.

   [3]  Guttman, E, Perkins, C. and J. Kempf, "Service Templates and
        service: Schemes", RFC 2609, July 1999.

   [4]  Bradner, S., "Key Words for Use in RFCs to Indicate Requirement
        Levels", BCP 14, RFC 2119, March 1997.

   [5]  Gulbrandsen, A. and P. Vixie, "A DNS RR for specifying the
        location of services (DNS SRV)", RFC 2052, October 1996.

   [6]  Droms, R., "Dynamic Host Configuration Protocol", RFC 2131,
        March 1997.

   [7]  Borella, M., Lo, J., Grabelsky, D. and G. Montenegro, "Realm
        Specific IP: Framework", RFC 3102, October 2001.





Kempf & Montenegro            Experimental                      [Page 9]

RFC 3105            Finding an RSIP Server with SLP         October 2001


   [8]  Perkins, C. and E. Guttman, "DHCP Options for Service Location
        Protocol", RFC 2610, July 1999.

   [9]  Naugle, J., Kasthurirangan, K. and G. Ledford, "TN3270E Service
        Location and Session Balancing", RFC 3049, January 2001.

   [10] Montenegro, G. and M. Borella, "RSIP Support for End-to-end
        IPSEC", RFC 3104, October 2001.

   [11] E. Guttman, "Service Location Protocol: Automatic Discovery of
        IP Network Services," IEEE Internet Computing, July/August 1999.
        Available at: http://computer.org/internet/ic1999/w4toc.htm

Authors' Addresses

   Questions about this document may be directed to:

   James Kempf
   NTT DoCoMo USA Labs
   181 Metro Drive, Suite 300
   San Jose, CA
   95110

   Phone: [phone]
   Email: [e-mail]


   Gabriel E. Montenegro
   Sun Microsystems
   Laboratories, Europe
   29, chemin du Vieux Chene
   38240 Meylan
   FRANCE

   Phone: [phone]
   EMail: [e-mail]















Kempf & Montenegro            Experimental                     [Page 10]

RFC 3105            Finding an RSIP Server with SLP         October 2001


Full Copyright Statement

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.



















Kempf & Montenegro            Experimental                     [Page 11]