Re: section 3.2.1/2 LFB outputs/inputs

On Wed, 2006-08-11 at 15:52 -0500, Joel M. Halpern wrote:
> If you can give me a bit more explanation of the hub-and-spoke case, 
> I'll try to work it in.

I could draw it, but hope this would suffice to describe it:
The Hub is a special LFB which deals with metadata +/- content
(typically metadata only) to decide routing of packets to the next(hop)
LFB in a topology. 
Typically setup is:
Two uni-directional spokes connect this LFB with every other LFB. The
src vertex maps to the LFB output and the LFB input maps to the dst
vertex[1]

The CE is capable of taking a linearly graphed policy description and
mapping it to this layout.
A few ASICs i know use this scheme.
 
> And 3.2, with the better description of what LFBs are, is a good 
> place to re-iterate that they are a descriptive construct, not an 
> implementation construct.

Ok, I have update #98 to state the above.

cheers,
jamal

[1]Probably more detail than needed : The connected to LFB may decide to
steal the packet or even inject a new packet. The hub needs to know of
these details (via metadata or otherwise) so it can terminate the
execution.