W3C Architecture Domain HTTP NG


42nd IETF, Chicago, August 1998

See also the HTTP-NG BOF Agenda.


Welcome and Discussion of Agenda

Henrik Frystyk Nielsen: Presentation of HTTP-NG Overview

Online slides are available


Current Status

Not Doing

Overview of Goals

HTTP/1.x experience

Gettys: people think we should build services on top of services; in today's world it's fragile, and difficult to build on this fragile base.

Why not…

HTTP/1.0 over WebMUX with POST and XML?

Web Characterisation Group

Bill Janssen: Presentation on NG Architecture

Online slides are available

NG Architecture

Top: Application Layer

Type System

Messaging Layer

Messaging to transport API

Transport Layers

WebMUX Transport

Provides four things in one layer:

These layers bundled together to provide more efficiency in terms of header space.

Jim Gettys: Presentation on WebMux


What pushed in the direction of WebMUX?

Is callback any different to passive FTP?

WebMUX Functions

Deadlock avoidance

Open Issues





How does this relate to CORBA IDL?
We're not tossing another distributed system into the mix: NG could be a substrate which allows CORBA, DCOM, RMI to be layered on top. Could today run Java code on top of NG.
Have one of the POST-based applications been ported?
No, but related: one test is to look at implementation of ILU's HTTP marshalling system (messageing layer for system like HTTP which allow);
Are there any plans to support transports other than TCP? What about UDP? Multicast IP?
Interested in running MUX over one of the new wireless transports. TCP is "just another transprot layer" at this point. The specs specify what's required of the transport.
Would be nice to be able to put performance monitoring in there (at what level should that be done?)
Could put it directly into the application interface design, or in the wire protocol's extension headers, or even as an additional transport layer stack.
What I really want is the ability to interleave req/resp, but also to separate data/metadata in response. Is it possible to tie multiple data streams on a single response?
Why not? Specifics are in the details of the application design.
Muxing on muxing, flow control on flow control - you're setting up a lot of potentially bad interactions here.
JG: Yes, I worry about that. I'd love to see something which solved these problems instead of TCP; this is our reaction to that, and want to hear from everyone who understood those problems in TCP to help us avoid making those mistakes.
Do we have an immediate need for this?
The perfect is the enemy of the good. I don't have an alternative right now, but I have problems to solve. Want to have real running code, so we can test and perform these experiments to see what the effect is.
If a WG comes out, thinking is it'll be in transport - because it takes careful thought of how these problems interact.
Could avoid the deadlock by dropping the data if too much is coming in.
One of strengths of HTTP is visibility of semantics over the wire. How visible are the semantics of HTTP-NG over the wire?
Not happy with the approach these documents encourage: it's like solving traffic congestion by raising the speed limit. Moving things faster between host and consumer helps get things faster, but is tied to the model that there's only one authority (source) for this data, and that the consumer has to go there to get it. This is broken.
What deployment scenario are you looking at? What's the advantage of being in the first 2% of adopters?
HTTP was a steam roller, XML is a steam roller, where does XML play in this model? Application/message/interface layer?
Can see where this is quicker on the client side, but don't believe it'll be quicker on the server-side as it's scaled up. Should probably take a look at the history of TCP multiplexing: Larry Peterson's paper "Multiplexing considered harmful". Noticed a couple of trends: 1. The idea that everything is a piece of HTTP data: FTP, video, etc are all over HTTP now; also service differentiation - surprised it's all over a single TCP
What is the security service?

Part Two

Continued questions

Should we continue?

Paul Bennett,
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