2.8.18 Reliable Server Pooling (rserpool)
NOTE: This charter is a snapshot of the 61st IETF Meeting in Washington, DC USA. It may now be out-of-date.
Last Modified: 2004-09-07
Lyndon Ong <email@example.com>
Maureen Stillman <firstname.lastname@example.org>
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Allison Mankin <email@example.com>
Jon Peterson <firstname.lastname@example.org>
Transport Area Advisor:
Jon Peterson <email@example.com>
Ned Freed <firstname.lastname@example.org>
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Description of Working Group:
The purpose of the WG is to develop an architecture and protocols for
the management and operation of server pools supporting highly reliable
applications, and for client access mechanisms to a server pool.
The WG will define architecture and requirements for management and
access to server pools, including requirements from a variety of
applications, building blocks and interfaces, different styles of
pooling, security requirements and performance requirements, such as
failover times and coping with heterogeneous latencies. This will be
documented in an Informational RFC.
The working group will focus on supporting high availability and
scalability of applications through the use of pools of servers. This
requires both a way to keep track of what servers are in the pool
and are able to receive requests and a way for the client to bind to
a desired server.
The Working Group will NOT address:
1) reliable multicast protocols - the use of multicast for reliable
server pooling is optional. Reliable multicast protocols will be
developed by the RMT WG.
2) synchronization/consistency of data between server pool elements,
e.g. shared memory
3) mechanisms for sharing state information between server pool
4) Transaction failover. If a server fails during processing of a
transaction this transaction may be lost. Some services may provide
a way to handle the failure, but this is not guaranteed.
The WG will address client access mechanisms for server pools,
1) An access mechanism that allows geographically dispersed servers in
2) A client-server binding mechanism that allows dynamic assignment of
client to servers based on load balancing or application specific
3) Support of automatic reconfiguration of the client/server binding in
case of server failure or administrative changes.
To the extent that new protocols are necessary to support the
requirements for server pooling, these will be documented in a
Standards Track RFC on client access to a binding service (i.e. name
The WG will also address use of proxying to interwork existing client
access mechanisms to any new binding service.
The WG will address server pool management and a distributed service to
support client/server binding, including:
1) A scalable mechanism for tracking server pool membership (incl.
2) A scalable protocol for performing node failure detection,
reconfiguration and failover, and otherwise managing the server pool
(supporting caching, membership, query, authentication,
3) A distributed service to support binding of clients to servers,
based on information specific to the server pool. Given that this
service is essential to access the server pool, a high degree of
availability is necessary.
4) A means for allowing flexible load assignment and balancing policies
The protocols and procedures for server pool management will be
documented in a Standards Track RFC.
The WG will address:
- transport protocol(s) that would be supported (eg. UDP, SCTP, TCP)
- any new congestion management issues
- relationship to existing work such as URI resolution mechanisms
Rserpool will consult with other IETF working groups such as Reliable
multicast, DNS extensions, AAA, URN, WREC and Sigtran as appropriate
and will not duplicate any of these efforts.
Goals and Milestones:
|Done|| ||Initial draft of Protocol Comparison |
|Done|| ||Initial draft of Threat Analysis |
|Done|| ||Initial draft of MIB |
|Done|| ||Initial draft of Rserpool Services document |
|Done|| ||Initial draft of Pool Management document |
|Done|| ||Initial draft of Rserpool Architecture document |
|Done|| ||Initial draft of Binding Service document |
|Done|| ||Submit Requirements document to IESG for Informational RFC |
|Done|| ||Submit Comparison document to IESG for Informational RFC |
|Done|| ||Initial draft of Resrpool Requirements document |
|Done|| ||Initial draft of TCP Mapping document |
|Done|| ||Initial draft of Applicability Statement |
|Mar 03|| ||Submit Services document to IESG for Informational RFC |
|Done|| ||Submit Architecture draft to IESG for Informational RFC |
|May 03|| ||Submit TCP mapping to IESG for Proposed Standard RFC |
|Done|| ||Submit Threat Analysis to IESG for Informational RFC |
|Aug 03|| ||Submit Binding Service and Pool Management to IESG for Proposed
Standard RFC |
|Aug 03|| ||Submit Applicability Statement to IESG for Informational RFC |
|Nov 03|| ||Submit MIB to IESG for Proposed Standard RFC |
Request For Comments:
|RFC3237|| I ||Requirements for Reliable Server Pooling |
Current Meeting Report
Reliable Server Pooling (Rserpool) minutes IETF #61
This meeting was attended by approximately 35 people.
The Rserpool architecture document was discussed. Changes in terminology will be added to the document. These changes are to clarify the architecture and make it easier for the reader to understand Rserpool.
The document contains several examples of applications of Rserpool. We are interested in adding a load balancing example due to the recent work of the design team in load balancing. Due to these changes we will reissue the document and perform another last call.
The Rserpool policy document was recently made a WG item. It describes a collection of optional pool policies. One recent change to the document is that it allows two modes of operation. Either the ENRP server can determine the next address or the PU can be given a list of IP addresses from which it selects an address. This change was debated and will be brought to the list.
The ASAP and ENRP protocols have been stable for a long time. Currently, changes have been suggested on the mailing list from people who are implementing Rserpool. Several changes have been incorporated into both protocols. The authors will update the terminology in the protocol documents to match the architecture document. We solicit and encourage more implementation feedback.
The load balancing design team has been meeting for two months and has made good progress. We are working with load balancing vendors to understand their requirements. Based on requirements, our goal is to identify changes to the Rserpool protocol and examine the advantages and disadvantages of several approaches. The design team is working on an internet draft to reflect load balancing requirements. This will be released after IETF #61 for review and comment. The design team will continue to meet.
An internet draft on high availability and Rserpool was discussed. The IPR on this work needs to be clarified before the WG can make a determination about making it a WG item.
The final talk was a discussion of Rserpool socket APIs. There is a draft not yet released with several authors. An overview of the functions was presented. The goal would be for this document to become an informational RFC. The draft will be sent to the list for review before deciding on its WG status.
ASAP Protocol Draft
Reliable Server Pooling Sockets API
Reliable Server Pooling Load Balancing Analysis
ENRP Changes from v09
Advanced Redundant Model Policy Support