On 2014-04-16 11:05 , Chris Welti wrote:
Hi Jeroen,
I can't follow what you're saying. As long as the announcements for the /18 and the /19s are valid, there is no reason for broken connectivity.
Of course there is. The /19 has precedence. Thus for sites that receive the /19 they will route over a much longer route than they should.
As far as I can see all anouncements are with origin by AS3303 as they should be. Also, connectivity tests via NLNOG ring prove that reachability is excellent all over the world to e.g. 84.253.0.1:
The RING does not cover all locations (yet, at least...)
As shown here:
https://stat.ripe.net/84.253.0.0%2F19#tabId=routing
All the sites that do receive the /19, especially for instance the 40% of the networks that receive it over for instance Sao Paolo, Brazil, or Moscow IX and do not get it more local will take the long trip around.
More specifics are evil and give weird routing in various locations.
Apparently Swisscom is looking into it though, thus hopefull the more specific will be gone soon and the problem will be gone too.
Greets, Jeroen
Am 16.04.2014 13:08, schrieb Jeroen Massar:
More specifics are evil and give weird routing in various locations.
Not always. When Init7 started to propagate more specifics to it's four /19 and /18, about 2gig of inbound traffic switched from transit links to peering links. This is real money and IMHO a valid reason to propagate selectivly more specific prefixes (i.E. two /20 for one /19).
Massiv deaggregation however is indeed evil, and there are just too many networks out there which do it unconsciously in a very stupid way.
Init7 is filtering away more than 10000 more specific prefixes from transit. To explain this a bit further I'd like to point to a presentation I gave a while ago during NANOG 54.
https://www.nanog.org/meetings/nanog54/presentations/Monday/Kuenzler.pdf
On 2014-04-16 17:55 , Fredy Kuenzler wrote:
Am 16.04.2014 13:08, schrieb Jeroen Massar:
More specifics are evil and give weird routing in various locations.
Not always. When Init7 started to propagate more specifics to it's four /19 and /18, about 2gig of inbound traffic switched from transit links to peering links. This is real money and IMHO a valid reason to propagate selectivly more specific prefixes (i.E. two /20 for one /19).
While you are absolutely right that it is good for traffic engineering (how the heck could I disagree with that? :)
When some other entity (especially a transit for other networks) filters those prefixes out, the results will vary.
The evil part is in the hidden problem it creates; not even the routing pollution (See also previous response...)
Massiv deaggregation however is indeed evil, and there are just too many networks out there which do it unconsciously in a very stupid way.
Init7 is filtering away more than 10000 more specific prefixes from transit. To explain this a bit further I'd like to point to a presentation I gave a while ago during NANOG 54.
https://www.nanog.org/meetings/nanog54/presentations/Monday/Kuenzler.pdf
I always liked: http://www.swinog.ch/meetings/swinog7/BGP_filtering-swinog.ppt
Always good to see what dogfood gets eaten... :)
Greets, Jeroen
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Fredy Kuenzler -
Jeroen Massar