Hi Fred. the picture is a start...
"Templin, Fred L" <fred.l.temp...@boeing.com> writes: > http://osprey67.com/stub-router.pdf > In this picture, the link I am concerned with is labeled > "NBMA Link" in the diagram. Please add an indication for what a typical "site" is. Are all of the stub networks considered part of the same site (i.e., same company, same house, etc.)? Also, you show "stub network 1", 2, 3, .etc. What is the internal structure of those networks (or does it matter)? In particular, there are presumably multiple links present in a stub network. Are there only "normal" routers internally? Can a "stub" router only exist on the NBMA link? Can you provide a specific example of the kind of link technology you are thinking of for the NBMA link? Is this DSL/Cable/ATM? Or just a hypothetical NBMA link? And who runs the NBMA link? Is this not a link operated by the Provider? I see there are "hosts" on the NMBA link. Can you provide examples of what kind of hosts? (I guess I really don't understand the deployment model you are assuming here... i.e., why wouldn't the NBMA link only have routers on it, with all hosts being behind a router.) > As you can see, there are stub networks connected to the link by > stub routers, and default routers that connect the link to provider > networks (which then connect to the Internet in some way). The link > is intentionally shown as two segments joined together by "..." to > show that it can be arbitrarily large and in some cases may contain > hundreds, thousands, or even more stub routers and stub networks. OK. > >From the diagram, only those routers labeled "default router" > should advertise default router lifetimes, M&O flags, PIOs, > and other RA information that provides operating parameters > for the link. If the routers labeled "stub router" also > advertised those kinds of parameters, then any hosts labeled > "host on NBMA link" would incorrectly update their link > parameters. As a simple example, if a router labeled "stub > router" advertised a non-zero default router lifetime in > an RA that was heard by a host labeled "host on NBMA link", > then the host would incorrectly configure a default route > that points to a stub network. OK. I understand this. That said, my first reactions would be: 1) is this a real deployment scenario? Who is setting up a network like this? Maybe they shouldn't do this and there are better approaches... 2) So what if the default route (on some hosts) points to the wrong thing, the stub router will presumably send a redirect for any traffic it is relaying, and the host will update its cache and from that point forward things are fine. Perhaps not "optimal" in a pure sense, but I certainly don't see this is as so broken a fix is needed... At least not without really understanding who is operating a network like this... Thomas -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
