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Re: [RRG] Sceptically on compact interdomain routing

While theoretically hierarchical routing uses logarithmic space, there are several ways in which that turns out not to be the case: 1) Even with best case address allocation, we will probably have one entry per top level AS. For a sense of scale, we will exhaust toe 16 bit AS number space in the near future. 2) In practice there are far more than 1 prefix per AS. This occurs for many reasons. The reason thet folks like Geof Huston have indicated is largest is multi-homing.
Hence, a rough analysis indicates that if the compact routing research can be made practical (which is a major open question) then even if IDs were assigned to ever site on the net, we would still end up with a smaller table than we have now. That is a pretty good result.
Clearly, there is still a lot of work to be done based on the research thus far. 9that's why its still research.)
I know that some of the engineers I have chatted with think this is all impossible to apply. I am not as skeptical, although I do have question about the base technology.
I think that there are going to be some interesting questions relating to applying policy, once we get that far. But I certainly am not asking not to continue investigating just because there are more hard problems further out. 

Yours,
Joel
PS: I am not a researcher with an account on arxiv, and it appears that accounts are intended for folks who will be submitting papers. 

At 09:58 AM 10/18/2005, Victor S. Grishchenko wrote:

Hi!

Here is a little criticism on "Toward compact interdomain routing"

        http://arxiv.org/abs/cs.NI/0510053

Generally, it is not all that simple, regarding applicability both of
hierarchical routing and compact routing.

First, hierarchical routing employs routing tables of logarithmical
size, so ASes aren't technically necessary for hierarchical routing
in general. So, the unweighted AS graph topology is not
an argument against hierarchical routing (in general).

Second, the existing two-tier global routing system (BGP for inter-
domain routing, plus some another solution, say OSPF, for intra-
domain routing) is equivalent to name-dependent compact routing.
So, another compact routing solution may be just stacked on top
of ASes. The solution is theoretically trivial, but suffers of
exponential stretch growth.

--
                        Victor S. Grishchenko
                        research fellow
                        Ural State University

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