[Also catching upŠ]
Bill:
I want to say up front that the proposal is not for this draft to be a
standards track document and to have everyone do it by default. It
provides a tool that people may want to use, as reflected by some interest
at the WG meeting. This is why we intended the draft to
I don't get how path information is lost in this draft. The AS Path is
not altered in any advertisement, so it's not like aggregation, where
you replace a series of AS' with a single AS, or anything like that.
Hi Russ,
10.1.0.0/16 AS path 12 5 4 2
10.1.1.0/24 AS path 12 1
The 12-1
The problem as I see it is many of those that operate in the BGP/DFZ don't
know what they are doing.
???
Then they shouldn't be using this technique. Or perhaps even running
BGP. Protocols provide rope. It's choice whether you make good things or
bad things with the rope provided.
:-)
Russ
Russ,
Hmmm, I don't think this is a consistent message.. When I attempted to
give people rope i.e BGP Persistence IETF chairs felt that this was too much
rope ?? IMO it takes very little rope to hang oneself so, let's be consistent
as a starting point...
Jim Uttaro
-Original
Suppose an Internet-connected network consists of site A and site B.
10.1.1.0/24 is advertised from and used by site A while 10.1.2.0/24 is
advertised from and used by site site B. Both sites advertise
10.1.0.0/16. Sites A and B are connected to each other, so if site A
receives a packet for
Alvaro,
10.1.0.0/16 AS path 12 5 4 2
10.1.1.0/24 AS path 12 1
The 12-1 path, 1 being a completely different origin AS than the
covering route's origin from 2, is lost when 10.1.1.0/24 is aggregated
into 10.1.0.0/16.
The path is not aggregated. Instead, the /24 would be marked as BOUNDED;
Russ,
Yes.
Sorry, but it is always true that by removing information you always
lose optimality (you increase stretch). Whether that removal is done at
the edge or in the core, the result is always the same. There are two
ironclad rules of routing:
- Removing information decreases optimal
On Oct 3, 2012, at 10:21 AM, Russ White ru...@riw.us wrote:
The problem as I see it is many of those that operate in the BGP/DFZ don't
know what they are doing.
???
Then they shouldn't be using this technique. Or perhaps even running
BGP. Protocols provide rope. It's choice whether
How do you know that the overlapping route takes traffic through the
same path? AS path != routing path and BGP is a distance-vector
protocol. Your router has no reliable knowledge of the routing path
more than 1 hop away.
All that matters is that I draw the same traffic into my AS, where
I'm not sure how to convince smaller folks to do the right thing if the big
people can't sort it out. (even with the right hooks).
You automate the process as much as possible, and let them sort out the
problems that result from their messed up shorter prefix routes.
:-)
Russ
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