The first month or so of the year saw an extraordinary amount of activity from the The Internet Engineering Steering Group (IESG), which approved the formation of nine new working groups and dissolution of six old ones. This month, things are still busy even if the IESG is not quite operating at the breakneck pace of January and February. Three new working groups have been approved, Site Multihoming in IPv6 (MULTI6), Application Exchange (APEX), and SIP for Instant Messaging and Presence Leveraging (SIMPLE).
Also of interest, a bit of networking protocol has finally passed into Internet history. STD 39, "Specification for the Interconnection of a Host and an IMP" (BBN Report 1822), published in 1981, was finally reclassified from an Internet Standard to an Historic specification.
Three New Working Groups
This month's new working groups provide an interesting snapshot of a range of networking concerns: multihoming for improved reliability and performance, use of a new application exchange architecture, and the application of an existing protocol (Session Initiation Protocol) to the instant messaging and presence application.
A multihomed site has more than one link to the Internet; those links can be provided by one or more ISPs. Network managers can multihome their sites for several reasons, but two are of particular importance. First, the security of knowing that if one link is brought down for whatever reason, the site will continue to have Internet connectivity. Second, the ability to do load balancing of traffic across multiple links to improve performance.
Right now, multihoming is done by having each ISP connection advertise the route to the site; this means that there are as many different routes to the same site as there are connections. As the number of multihomed sites increases, the difficulty of maintaining a stable routing infrastructure increases as well.
The new Site Multihoming in IPv6 (MULTI6) working group, in the Operations and Management Area of the Inetnet Engineering Task Force, is chartered to define the current state of the art in multihoming with IPv4, and "explore alternative approaches with better scaling properties." That means looking at"multi-homing solutions that tend to minimise adverse impacts on the end-to-end routing system and limit the number of prefixes that need to be advertised in the Default-Free Zone (DFZ)."
Given that IPv6 is still free from legacies that might interfere with a scalable multihoming architecture, MULTI6 will investigate how best to use the special features of IPv6 to facilitate multihoming.
The Application Exchange (APEX) working group, in the IETF Applications Area, is chartered to "specify protocols and data formats that define a relaying mesh service for loosely-coupled Internet applications, along with specifying services to provide access control and rendezvous-by-subscription."
The APEX focus will be on defining services for instant messaging and online presence applications, with a key goal being "focused on assuring very low latency between posting and delivery." In other words, making sure that messages get there quickly to enable real-time conversations.