Hi folks, Can anyone tell me about a situation in which a route which was not valley free was not a result of a misconfiguration or a bad actor? For those who don't recall the terminology, a network path is valley free if it crosses exactly zero or one free peering links when traveling between the two endpoints. Thanks, Bill Herrin -- William D. Herrin ................ herrin@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
On Wed, 05 Mar 2014 15:23:55 -0500, William Herrin said:
Hi folks,
Can anyone tell me about a situation in which a route which was not valley free was not a result of a misconfiguration or a bad actor? For those who don't recall the terminology, a network path is valley free if it crosses exactly zero or one free peering links when traveling between the two endpoints.
Assume 3 providers A B and C, where you have a single-homed customer on A and a single-homed customer on C, and A and C don't peer. Traffic may end up going thorugh an A-B peering and a B-C peering. And whether A-B and B-C are a free peering or a paid transit is a business deal, outside the scope of BGP, unless you want to abuse communities... Are A and/or C "bad actors" for not peering? Jury is still out on that one.
On Wed, Mar 5, 2014 at 4:00 PM, <Valdis.Kletnieks@vt.edu> wrote:
On Wed, 05 Mar 2014 15:23:55 -0500, William Herrin said:
Can anyone tell me about a situation in which a route which was not valley free was not a result of a misconfiguration or a bad actor? For those who don't recall the terminology, a network path is valley free if it crosses exactly zero or one free peering links when traveling between the two endpoints.
Assume 3 providers A B and C, where you have a single-homed customer on A and a single-homed customer on C, and A and C don't peer. Traffic may end up going thorugh an A-B peering and a B-C peering. And whether A-B and B-C are a free peering or a paid transit is a business deal, outside the scope of BGP, unless you want to abuse communities...
Are A and/or C "bad actors" for not peering? Jury is still out on that one.
Hi Valdis, It's that business deal I want to hear about. When A-B and B-C are free peering but the traffic goes A-B-C for some reason other than a misconfiguration or deliberate abuse. On or off list, I'd like to know about real-life use cases where folks do this on purpose. Regards, Bill Herrin -- William D. Herrin ................ herrin@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
I can't think of any circumstances where the business "B" would be content transit traffic between A and C without some form of compensation. That compensation may not involve payment for bits, however. In theory, the compensation might be derived from something occurring at the application layer, but even in those cases that business relationship is probably not apparent from looking at prefix advertisements. Business B is probably using b2b user agents, gre encap or some other method that makes both legs look like independent IP flows to network A and B. Interesting question, though. Dave -----Original Message----- From: William Herrin [mailto:bill@herrin.us] Sent: Wednesday, March 05, 2014 2:08 PM To: Valdis Kletnieks Cc: nanog@nanog.org Subject: Re: valley free routing? On Wed, Mar 5, 2014 at 4:00 PM, <Valdis.Kletnieks@vt.edu> wrote:
On Wed, 05 Mar 2014 15:23:55 -0500, William Herrin said:
Can anyone tell me about a situation in which a route which was not valley free was not a result of a misconfiguration or a bad actor? For those who don't recall the terminology, a network path is valley free if it crosses exactly zero or one free peering links when traveling between the two endpoints.
Assume 3 providers A B and C, where you have a single-homed customer on A and a single-homed customer on C, and A and C don't peer. Traffic may end up going thorugh an A-B peering and a B-C peering. And whether A-B and B-C are a free peering or a paid transit is a business deal, outside the scope of BGP, unless you want to abuse communities...
Are A and/or C "bad actors" for not peering? Jury is still out on that one.
Hi Valdis, It's that business deal I want to hear about. When A-B and B-C are free peering but the traffic goes A-B-C for some reason other than a misconfiguration or deliberate abuse. On or off list, I'd like to know about real-life use cases where folks do this on purpose. Regards, Bill Herrin -- William D. Herrin ................ herrin@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
The AS I worked at back in the day did to a degree for willing parties. Mostly small ISPs who all knew each other. We had at the time 3 regional hub locations with interlinks, and peered settlement free with 2 - 3 ASs in 1 of the locations, and 1-2 ASs each in the other 2 locations, all of which could opt to allow their prefixes to be heard by the others via communities. -Blake On Wed, Mar 5, 2014 at 3:48 PM, Siegel, David <David.Siegel@level3.com>wrote:
I can't think of any circumstances where the business "B" would be content transit traffic between A and C without some form of compensation. That compensation may not involve payment for bits, however. In theory, the compensation might be derived from something occurring at the application layer, but even in those cases that business relationship is probably not apparent from looking at prefix advertisements. Business B is probably using b2b user agents, gre encap or some other method that makes both legs look like independent IP flows to network A and B.
Interesting question, though.
Dave
-----Original Message----- From: William Herrin [mailto:bill@herrin.us] Sent: Wednesday, March 05, 2014 2:08 PM To: Valdis Kletnieks Cc: nanog@nanog.org Subject: Re: valley free routing?
On Wed, Mar 5, 2014 at 4:00 PM, <Valdis.Kletnieks@vt.edu> wrote:
On Wed, 05 Mar 2014 15:23:55 -0500, William Herrin said:
Can anyone tell me about a situation in which a route which was not valley free was not a result of a misconfiguration or a bad actor? For those who don't recall the terminology, a network path is valley free if it crosses exactly zero or one free peering links when traveling between the two endpoints.
Assume 3 providers A B and C, where you have a single-homed customer on A and a single-homed customer on C, and A and C don't peer. Traffic may end up going thorugh an A-B peering and a B-C peering. And whether A-B and B-C are a free peering or a paid transit is a business deal, outside the scope of BGP, unless you want to abuse communities...
Are A and/or C "bad actors" for not peering? Jury is still out on that one.
Hi Valdis,
It's that business deal I want to hear about. When A-B and B-C are free peering but the traffic goes A-B-C for some reason other than a misconfiguration or deliberate abuse. On or off list, I'd like to know about real-life use cases where folks do this on purpose.
Regards, Bill Herrin
-- William D. Herrin ................ herrin@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
On Wed, 05 Mar 2014 21:48:26 +0000, "Siegel, David" said:
I can't think of any circumstances where the business "B" would be content transit traffic between A and C without some form of compensation. That compensation may not involve payment for bits, however.
If ASN B is a cooperative venture (such as a regional network) funded by A, C, and several others for mutual gain, it's not at all out of the question.
It's that business deal I want to hear about. When A-B and B-C are free peering but the traffic goes A-B-C for some reason other than a misconfiguration or deliberate abuse. On or off list, I'd like to know about real-life use cases where folks do this on purpose.
As far as I understand some NRENs do that in Europe. Check out AS1853 and AS-ACONETTOVIX in the RIPE whois. "A" networks are the peers a VIX, "B" is ACONET, "C" networks are CESNET, SANET, and PIONIER. DTAG's looking glass shows this path to SANET: sh ip bgp regexp _2607_ BGP table version is 0, local router ID is 217.239.38.165 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, R Removed Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path *>i147.175.0.0 194.25.5.150 100 0 1853 2607 i *>i147.213.0.0 194.25.5.150 100 0 1853 2607 i *>i147.232.0.0 194.25.5.150 100 0 1853 2607 i *>i158.193.0.0 194.25.5.150 100 0 1853 2607 i *>i158.195.0.0 194.25.5.150 100 0 1853 2607 i *>i158.197.0.0 194.25.5.150 100 0 1853 2607 i *>i192.108.130.0 194.25.5.150 100 0 1853 2607 i *>i192.108.131.0 194.25.5.150 100 0 1853 2607 i *>i192.108.132.0/23 194.25.5.150 100 0 1853 2607 i *>i192.108.138.0 194.25.5.150 100 0 1853 2607 i *>i192.108.149.0 194.25.5.150 100 0 1853 2607 i *>i193.87.0.0/16 194.25.5.150 100 0 1853 2607 i *>i194.1.0.0/17 194.25.5.150 100 0 1853 2607 i *>i194.160.0.0/16 194.25.5.150 100 0 1853 2607 i Total number of prefixes 14 Regards, András
I have worked for the middle network when I was responsible for a government network - typically we were the middle network. Logic was it was good for citizens for us to essentially act like a peering exchange for certain types of entity (who also typically were government affiliated). One I can think of was to allow a full mesh of video education between various institutions - it was the right thing to do for all entities involved and I facilitated it through the network I was affiliated with. You might also think about the circumstance of two government subcontractors working on a common project or interfacing with each other's systems on behalf of a common customer. The middle network is paying each end to connect to the middle but is providing reverse transit between them (I.E. the end entities are paid to transit the middle!), although the contracts aren't exactly phrased to say that! A lot of time, this may be done with static routes, but it could easily be done with BGP and the end effect is the same. I have never heard the term valley free. Where does it come from? On Mar 5, 2014 1:25 PM, "William Herrin" <bill@herrin.us> wrote:
Hi folks,
Can anyone tell me about a situation in which a route which was not valley free was not a result of a misconfiguration or a bad actor? For those who don't recall the terminology, a network path is valley free if it crosses exactly zero or one free peering links when traveling between the two endpoints.
Thanks, Bill Herrin
-- William D. Herrin ................ herrin@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
On 6 mrt. 2014, at 02:18, Joel Maslak <jmaslak@antelope.net> wrote:
I have never heard the term valley free. Where does it come from?
This paper, which is a must-read for anyone interested in BGP: Stable internet routing without global coordination By Lixin Gao and Jennifer Rexford http://dl.acm.org/citation.cfm?id=504612
once upon a time, provider A and provider P were having a peering war, and provider V provided valley transit for P's prefixes to A. it was not meant to be seen publicly, but the traceroutes were posted to nanog, or maybe it was com-priv at the time. this is far from the only time this has happened. randy
Having been employed by a provider V in one such example of the below, I viewed it as a temporary, partial transit relationship. Does such a situation meet Bill's original definition? -----Original Message----- From: Randy Bush [mailto:randy@psg.com] Sent: Thursday, March 06, 2014 7:42 AM To: William Herrin Cc: North American Network Operators' Group Subject: Re: valley free routing? once upon a time, provider A and provider P were having a peering war, and provider V provided valley transit for P's prefixes to A. it was not meant to be seen publicly, but the traceroutes were posted to nanog, or maybe it was com-priv at the time. this is far from the only time this has happened. randy
On Fri, Mar 7, 2014 at 11:18 AM, Siegel, David <David.Siegel@level3.com> wrote:
Having been employed by a provider V in one such example of the below, I viewed it as a temporary, partial transit relationship. Does such a situation meet Bill's original definition?
Hi David, I think you have the right of it. That the recipient elects only to use the link for a limited set of destinations is an ordinary part of transit service. In Randy's example, a peering link was converted to a transit link on a short term basis. Regards, Bill Herrin -- William D. Herrin ................ herrin@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
On Fri, Mar 7, 2014 at 12:52 PM, Randy Bush <randy@psg.com> wrote:
I think you have the right of it. That the recipient elects only to use the link for a limited set of destinations is an ordinary part of transit service. In Randy's example, a peering link was converted to a transit link on a short term basis.
you know the term?
Hi Randy, For my interests I don't care about the duration. Five minutes or five years it's all the same to me. I care about the characteristics of the relationship while it's ongoing. Regards, Bill Herrin -- William D. Herrin ................ herrin@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
On Wed, Mar 5, 2014 at 12:23 PM, William Herrin <bill@herrin.us> wrote:
Hi folks,
Can anyone tell me about a situation in which a route which was not valley free was not a result of a misconfiguration or a bad actor? For those who don't recall the terminology, a network path is valley free if it crosses exactly zero or one free peering links when traveling between the two endpoints.
Isn't that the way most of the IPv6 internet ran for many years? ISP A -> 6939 <- ISP B, settlement-free connections all around? It's what established 6939 as the core of the IPv6 internet. Matt
Thanks, Bill Herrin
-- William D. Herrin ................ herrin@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
On Thu, Mar 6, 2014 at 9:23 PM, Matthew Petach <mpetach@netflight.com> wrote:
On Wed, Mar 5, 2014 at 12:23 PM, William Herrin <bill@herrin.us> wrote:
Can anyone tell me about a situation in which a route which was not valley free was not a result of a misconfiguration or a bad actor? For those who don't recall the terminology, a network path is valley free if it crosses exactly zero or one free peering links when traveling between the two endpoints.
Isn't that the way most of the IPv6 internet ran for many years? ISP A -> 6939 <- ISP B, settlement-free connections all around? It's what established 6939 as the core of the IPv6 internet.
Hi Matthew, By peering I mean a link on which the two participants offer and accept substantially fewer routes than "the rest of the Internet." Usually only the routes for each participant's respective customers. The clever folks at HE provided full IPv6 transit as a loss leader which enhanced their market position (put them on the map quite frankly). That's not a "valley" in this context. I'm really intrigued by the multiple reports of RENs creating a sort of shadow network where other RENs are permitted to cross their internal backbone at no cost but not access their general Internet transit. That does seem to be a valley. Is anybody outside the Research and Education industry doing this sort of thing? Regards, Bill Herrin -- William D. Herrin ................ herrin@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
participants (9)
-
Blake Dunlap -
Iljitsch van Beijnum -
Joel Maslak -
JÁKÓ András -
Matthew Petach -
Randy Bush -
Siegel, David -
Valdis.Kletnieks＠vt.edu -
William Herrin