Hi all, Probably a silly question, but can anyone explain to me this: 3561 3356 9031 {35821,35821,35821,35821} i To explain it a bit better, I'm looking at real routing information from routeviews (#3). According to RFC 4271 (9.2.2.2 Aggregating Routing Information):
For the purpose of aggregating AS_PATH attributes, we model each AS within the AS_PATH attribute as a tuple <type, value>, where "type" identifies a type of the path segment the AS belongs to (e.g., AS_SEQUENCE, AS_SET), and "value" identifies the AS number. ... No tuple of type AS_SET with the same value SHALL appear more than once in the aggregated AS_PATH.
Am I misreading things, or is this path information out of spec? Cheers Heath
please support draft-wkumari-deprecate-as-sets-00.txt I just noticed that then - looking through idr list archives. I'll give it a read.. What is the best way to support, just email the list?
i am not sure, as truth be told, i do not follow idr. a fair but not sure inference from its name (not being draft-ietf-idr-...) is folk need to push for it to be taken on as a wg work item/draft. the ietf ops cabal was certainly behind it, and encouraged warren to don the kevlar and venture forth. and, while you are tilting at windmills, you can help push the full prefix match draft, draft-kohno-ipv6-prefixlen-p2p-02.txt, in 6man. now all we need is someone to write draft-deprecate-ipv6-subnet-anycast randy
Probably a silly question, but can anyone explain to me this: 3561 3356 9031 {35821,35821,35821,35821} i please support draft-wkumari-deprecate-as-sets-00.txt Mere deprecation does not stop propagation of such paths.
over time, routers will no longer generate or accept in the meantime, i will watch while you and king canute try to cure st00pidity. randy
On Sep 22, 2010, at 4:15 PM, Florian Weimer wrote:
* Randy Bush:
Probably a silly question, but can anyone explain to me this: 3561 3356 9031 {35821,35821,35821,35821} i
please support draft-wkumari-deprecate-as-sets-00.txt
Mere deprecation does not stop propagation of such paths.
That's very true, but it *does* move us in the right direction -- saying "Aggregation that results in AS_SETs is prohibited, off with your head" isn't going to fly in the IDR WG when there are routes that use them... Suggesting the people do not perform aggregation that results in the creation of AS_SETs (and AS_CONFED_SETs), and that operators filter such announcements will lead to a time where they just don't exist any more [0] (and then can be removed from the protocol). We are also specifying that new BGP work does not need to support AS_.*SET ;-) W -- "Being the Fun-Police in the global Internet is a thankless - and probably futile - task." -- R. Whittle ("draft-whittle-sram-ip-forwarding-01.txt")
just to uncloak a bit. when we first decided to look at deprecating as-sets et alia, we begged olaf maennel to analyse the use thereof. the following is edited from internal email from early august. we then begged one of our number, warren, to do the dirty, and he was kind enough to do so. we owe him. --- using data from ripe r00 years total real stable as-sets as-sets 7 4 2 6 6 2 5 20 3 4 22 5 3 64 16 2 214 87 1 875 289 years stable is how many years that as-set was announced for that prefix. total as-sets is the number of prefixes that had any as-set. real as-sets is the number of prefixes with as-sets which were not singleton asns and were not private asns. olaf scanned for ten years but none were stable for more than seven. in ten years, 1205 different prefixes with as-sets were seen. removing private asns and removing singletons left only 404 prefixes over the ten years. he did not check for covering prefixes, i.e. two prefixes with the same as-set where one was a sub-prefix of the other, longer, one. and i suspect the data are somewhat self-similar. i.e. the 289 that were stable for the last year may have shorter term components which were much higher. i.e. looking at data for a week or a day may give higher values. a graph which should be pretty self-explanitory may be found at http://archive.psg.com/fraction-and-absolute-number-of-ASsets-in-table-over-... it is interesting that, at no time, i.e. in no single rib dump, were there more than 23 prefixes with as-sets. while this is suspicious, it seems to be true. randy
participants (5)
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Christopher Morrow -
Florian Weimer -
Heath Jones -
Randy Bush -
Warren Kumari