On Dec 27, 2009, at 7:43 PM, Brian E Carpenter wrote:
Hi,
On 2009-12-28 14:17, Xu Xiaohu wrote:
...
This argument fails for exactly the same reason that geographically
based BGP aggregation fails.
Brian, who has ever done it ?
Nobody, as far as I know.
Why do you say this and what do you mean by saying this ?
There have been a lot of geo-based or metro-based proposals over
the years. Most recently, draft-hain-ipv6-geo-addr.
As far as I know, none of them has ever been deployed, because
this isn't how Internet economics works. There is no financial
incentive to deploy geographically based exchange points which also
act as address delegators to customers. (Note, there is no technical
argument against it. But nobody knows how to make money out of it.)
the above comment seems alluding to the long historical debate in geo-
based addressing, that the young folks here may not be totally aware
(I wish I were one of you people:). So here are a few pointers to
related material.
The concept was a rather old one, Greg Finn had some related proposal
back in early 80s (I didn't bother to hunt down the URL but I believe
a long tech report is still on the web).
In the early days of IPv6 design, Steve Deering gave a strong pushing
in this direction. The best ref is probably his plenary talk at July
1995 IETF meeting:
"Metro-Based Addressing",
ftp://ftp.ietf.org/ietf-online-proceedings/95jul/presentations/allocation/deering.slides.ps
This proposal was considered and debated at the time, but did not fly
(though effort in that direction continued on, e.g. the draft-hain-
ipv6-geo-addr mentioned above), mainly due to the reason that has been
articulated in this thread of exchanges: the model does not match the
ISP economics.
However as it happens to any debate, opinions often swing further than
proper. From time to time one hears the interpretation from that
debate as "geo info cannot be used in routing" which is not the case.
What that debate taught us (at least me) is that, for routing
decisions, ISP info must take the high order bit.
However after that high order bit is taken into account, geo info can
be very useful to further optimize the routing decisions.
as a simple evaluation, we used the BGP data from Rotueviews and RIPE
for a measurement study, the result is reported in a paper a few years
back:
"Geographically Informed Inter-Domain Routing"
http://www.cs.ucla.edu/~rveloso/papers/giro.pdf
or if you just want a quick look of the idea, here is the presentation
slides:
http://www.cs.ucla.edu/~rveloso/papers/07ICNP_giro.ppt
Lixia
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