Subject: WG Review: Link-Enhancing Transport Intermediary Communication (letic)

From: The IESG <[email-masked]>
Date: Wed, 11 Feb 2004 13:53:03 -0500

A new IETF working group has been proposed in the Transport Area.  The IESG 
has not made any determination as yet. The following description was submitted, 
and is provided for informational purposes only.  Please send your comments 
to the IESG mailing list ([email-masked]) by February 18th.

 Link-Enhancing Transport Intermediary Communication (letic)
 -----------------------------------------------------

 Current Status: Proposed Working Group

 Description of Working Group:

 Several types of physical links increasingly used for Internet
 connectivity today possess undesirable characteristics, such as high
 loss, high delay, and low reliability (including short-term intermittent
 availability). Radio links in wireless networks (e.g., GPRS or CDMA
 2000) are examples of such links. The presence of one of more of these
 types of links anywhere in an end-to-end path can result in performance
 degradation of several Internet protocols and services, although many of
 these links frequently appear as 'access links' (the link closest to the
 client endpoint). 

 Transport intermediaries have been used to mitigate performance
 degradation caused by problematic links (see RFC 3135). Such
 intermediaries typically reside in nodes (e.g., base stations, or access
 points) located at the ends of problematic links (although this is not a
 requirement -- our intended scope is for any links, edge or otherwise).
 Somewhat more formally, a transport intermediary may be defined as
 follows: 

 An IP-addressable entity, conceived to be along the path of two
 endpoints interacting (via IP unicast) that inspects and/or modifies
 traffic passing through it up to and possibly including the transport
 layer (but not performing so-called "data" transformations)

 To date, there has been no systematic investigation of existing
 mechanisms to request, discover, control, and obtain information from
 such intermediaries, and there is no solid guidance for designing such
 mechanisms for future intermediaries. In particular, there is no common
 understanding of the security requirements for such mechanisms. The
 working group will fill this void by first investigating the existing
 state-of-the-art and then formulating requirements for standard
 mechanisms to allow:

 + Transport intermediaries to signal to endpoints (or vice-versa) their
 existence, their capabilities, desires, or other useful information
 (e.g., knowledge of changing link conditions) 

 + Intermediaries and endpoints to communicate in a secure manner and to
 establish security associations if required

 Assuming the formulation is successful (i.e., it yields useful
 requirements that point towards a feasible solution), the working group
 will then develop the common framework and the standard means.
   
 While conducting its work, the working group will take into
 consideration the related work in other working groups, including pilc,
 ipsec, midcom, opes, nsis and send.
   
 The deliverables of the working group within its first 9 months of
 existence will include Informational RFCs that present

 1. A survey of existing and planned/desired transport intermediaries and
 how they interact with endpoints. Specific attention is to be paid to
 the discovery process, security needs, and maintenance of state (e.g.,
 if endpoints and intermediaries expect to remain in contact with each
 other). In addition, for those systems providing dynamic information
 about the network (e.g., link conditions) to endpoints, a list of what
 information is conveyed by the intermediary and how it is used by an
 endpoint will be included.

 2. A determination of which services the WG will focus on (termed
 "in-scope transport intermediary services") and to what extent these
 particular services require secure interactions that might impact
 end-to-end security.

 3. The requirements of a (future) secure transport intermediary protocol
 based on the findings of #2. Such a protocol may support, for example,
 explicit knowledge of and optional consent from endpoints that may
 involve negotiation and security association establishment between an
 endpoint and intermediary.