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Toward Compact Interdomain Routing [Re: [RRG] recent progress in routing research]



I'll put this on the list in the interest of seeing if this would generate wider discussion and/or comments. I also trimmed the Cc: list a bit..

On Sat, 20 Aug 2005, Dmitri Krioukov wrote:
For a list of most important papers on compact routing, see Section
5 of http://arxiv.org/abs/cs.NI/0508021 Of course, there are much
more results in this area. One can find them following the reference
links. On the other hand, for a somewhat *shorter* version of the
compact routing reference list, see 'Compact routing background
reading' section at http://rr-fs.caida.org/

I read the "Toward Compact Interdomain Routing" paper mentioned above. I think it's a very good contribution in summarizing to the routing community on what has been done elsewhere and adding quite a bit of good analysis besides.


I noted two significant things worth of commenting:

1) section 2 states "organization (AS) boundaries do offer a natural level of aggregation and abstraction of routing information" and similar other things. Though I personally would like that to be the case, it appears that at least in some cases it does not hold. For example, check out papers "A Measurement-Based Analysis of Multihoming" and "A Comparison of Overlay Routing and Multihoming Route Control" (from SIGCOMM's 2003 and 2004, respectively).

It seems that some want more fine-grained traffic optimization and/or balancing than based on the AS -- for example, they want to do it on per-prefix basis, with non-global propagation properties (e.g., NOPEER attribute).

In that light, it seems that while AS-level abstraction would work in some cases (as an ISP, it would certainly work for us), it might be insufficient in the more general case. Though it being insufficient might also be a GOOD thing, to avoid global routing table pollution.

But all in all, I think the paper needs to be a bit more analysis (or refer to such) on whether AS-level abstraction is really a drop-in replacement for the current model.

2) In section 6, you mention that RT size for the real Internet topology could be even as low as 50 entries. It would be interesting to see what that topology would look like. Would this be available in a graph or some other format for study? (and comparison with the current topology...)

3) In section 6, you refer to BGP's convergence cost of O(n!) with reference to Labovitz et al's "Delayed Internet Routing Convergence". While algorithmically this might be true (if everyone gave transit to everyone else), a better comparison point would be "The Impact of Internet Policy and Topology on Delayed Routing Convergence" (Infocom 2003).

--
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings

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