Re: T1 vs. T2 [WAS: Apology: [Tier-2 reachability and multihoming]]
On Mon, 28 Mar 2005, John Dupuy wrote:
I'll be brief, but I do want to perhaps word Alex's definition in a different way that might be more useful.
Even "tier 1" providers regularly trade transit. They must since no single network is connected to all the other ones. Not even close. Even UUNet (ASN 701), arguably the most-connected network on the planet, only connects to a fraction of the possible peerings.
701 is not the most connected, it has only customers and a restrictive set of peers? you dont need to peer with all networks tho, if all networks are buying from 701 or one of its peers then it will get those routes via peering not transit or transit trades... you seem to be forgetting what peering is. and if you peer with all networks in the 'transit free zone' then you too become transit free also.
The true definition is more vague: if a peering or transit circuit between A or B is taken down, who will be hurt the most: A or B? If it predominantly B, and much less A, then A is "more Tier 1" and B is of a "lesser Tier". If they are equally hurt, they the are of equal status. Essentially, "Tier 1" is whatever the other "Tier 1" providers believe at the moment is "Tier 1". It is self-referential and not distinct at all.
i believe the distinction exists as shown above ie transit free.. as to why this might be considered a goal i'm not sure, its not obvious that transit free is cheaper than buying transit! this thing about 'who hurts most' is an entirely different topic and has nothing to do with who is in the transit free zone. altho destructive depeering does seem to be common practice within that zone :)
This is, frustratingly, a very non-technical definition. But it seems to map with what I've actually seen the industry do.
thats because non-technical definitions mean anyone can call themselves anything they like.. wiltel recently spammed me to buy their 'tier1 transit'.. presumably they are tier1 within their own definition of tier1. if you want to be technical tho, and aiui we are a technical forum, then tier1 means transit free. i reaffirm my earlier point - but why care, isnt it about cost and reliability, and as peering and transit are about the same cost who cares who you dont peer with Steve
John
At 09:17 AM 3/28/2005, Stephen J. Wilcox wrote:
On Mon, 28 Mar 2005, Randy Bush wrote:
> > Firstly, peering isn't binary. Is peering vs transit a distinction based on > > routes taken / accepted & readvertised, or on cost? Does "paid for peering" > > count as peering or transit? If you pay by volume? If you pay for "more than > > your fair share" of the interconnect pipes? (if the latter, I am guessing > > there are actually no Tier 1s as everyone reckons they pay for more than > > their fair share...). > > pay? did i say pay? i discussed announcement and receipt of prefixes. this > was not an accident. it is measurable.
i also avoided money.. i dont think its that relevant, everyone is paying for peering or transit in one form or another, i dont think any peering is free (free != settlement free)
> > Secondly, it doesn't cover scenarios that have have happened in the past. > > For instance, the route swap. EG Imagine networks X1, X2, X3, X4 are "Tier > > 1" as Randy describes them. Network Y peers with all the above except X1. > > Network Z peers with all the above except X2. Y & Z peer. To avoid Y or Z > > needing to take transit, Y sends Z X2's routes (and sends Z's routes to X2 > > routes marked "no export" to X2's peers), and Z sends Y X1's routes (and > > sends Y's routes to X1 marked "no export" to X1's peers). Perhaps they do > > this for free. Perhaps they charge eachother for it and settle up at the end > > of each month. Perhaps it's one company that's just bought another.
"transit (n). The act of passing over, across, or through; passage."
whether it is a settlement arrangement or a mutual swap, they do NOT have peering, they ARE transitting and by our definition are not transit-free (and hence not tier1)
however alex, you do highlight an excellent point - things are not as simple as 'tier1, tier2', there are complicated routing and financial arrangements in operation, which brings me back to my earlier point: does it matter what a network is paying for some connectivity providing they deliver to you the connectivity you need at the quality you desire?
Steve
and if you peer with all networks in the 'transit free zone' then you too become transit free also.
er.. hate to rain on your parade but if I peer with everyone i need/want to exchange traffic with, i am transit-free, even if I -NEVER- touch any other part of the commercial Internet... my packets get to where they need to go and all packets I want get to me. my life is good ... even if I only appear as vestigal to the commercial Internet, if I appear at all. how would you classify such a network? T1, T2, ODDBALL-0, non-Internet-265, ??? --bill
On Mar 28, 2005, at 8:29 PM, bmanning@vacation.karoshi.com wrote:
and if you peer with all networks in the 'transit free zone' then you too become transit free also.
er.. hate to rain on your parade but if I peer with everyone i need/want to exchange traffic with, i am transit-free, even if I -NEVER- touch any other part of the commercial Internet... my packets get to where they need to go and all packets I want get to me. my life is good ... even if I only appear as vestigal to the commercial Internet, if I appear at all.
Absolutely correct.
how would you classify such a network? T1, T2, ODDBALL-0, non-Internet-265, ???
I doubt it is a tier. I am certain it is not an "Internet" network if it does not have connectivity to substantially all other Internet networks. -- TTFN, patrick
On Mon, Mar 28, 2005 at 09:15:53PM -0500, Patrick W Gilmore wrote:
On Mar 28, 2005, at 8:29 PM, bmanning@vacation.karoshi.com wrote:
and if you peer with all networks in the 'transit free zone' then you too become transit free also.
er.. hate to rain on your parade but if I peer with everyone i need/want to exchange traffic with, i am transit-free, even if I -NEVER- touch any other part of the commercial Internet... my packets get to where they need to go and all packets I want get to me. my life is good ... even if I only appear as vestigal to the commercial Internet, if I appear at all.
Absolutely correct.
how would you classify such a network? T1, T2, ODDBALL-0, non-Internet-265, ???
I doubt it is a tier. I am certain it is not an "Internet" network if it does not have connectivity to substantially all other Internet networks.
begs the definition of "internet networks" ... It has IP connectivity to the other IP networks of interest. For networks that are not of interest, there is no expressly defined connectivity. The term Internet has devolved into a series of interconnected -COMMERCIAL- networks and from that viewpoint, anyone on a non-commercial network, that has no desire to be connected to a commercial network, is relegated, BY THE COMMERCIAL OPERATORS, to "intranet" status. The historical term - INTERNET - reflected a catanet of networks that used IP for packet delivery. with the inclusion of robust policy expression on network "edges" - full, global, end2end reachability truely became a myth ... and the term Internet became based on a shifting foundation. So from a commercial networking perspective, yes, my network is vestigal. But it is transit-free and has full connectivity to all of the parties it wants/needs to talk to. So by that definition (e.g. transit-free) its a Tier-1. Sort of points out some of the weaknesses in terminology and the biases in a single viewpoint. as usual, YMMV. --bill
TTFN, patrick
er.. hate to rain on your parade but if I peer with everyone i need/want to exchange traffic with, i am transit-free, even if I -NEVER- touch any other part of the commercial Internet... my packets get to where they need to go and all packets I want get to me. my life is good ... even if I only appear as vestigal to the commercial Internet, if I appear at all.
how would you classify such a network?
billnet. we're used to it. randy
On Mon, Mar 28, 2005 at 06:47:30PM -0800, Randy Bush wrote:
er.. hate to rain on your parade but if I peer with everyone i need/want to exchange traffic with, i am transit-free, even if I -NEVER- touch any other part of the commercial Internet... my packets get to where they need to go and all packets I want get to me. my life is good ... even if I only appear as vestigal to the commercial Internet, if I appear at all.
how would you classify such a network?
billnet. we're used to it.
randy
and you have even used it on occasion. :) --bill
On Tue, 29 Mar 2005, bmanning@vacation.karoshi.com wrote:
and if you peer with all networks in the 'transit free zone' then you too become transit free also.
er.. hate to rain on your parade but if I peer with everyone
these are not the words of someone hating to rain on me!
i need/want to exchange traffic with, i am transit-free, even if I -NEVER- touch any other part of the commercial Internet...
mmm yeah but in the context we have here of ISPs providing connectivity to other ISPs or enterprises this isnt very realistic so i dont see the point of arguing the technicality.
my packets get to where they need to go and all packets I want get to me. my life is good ... even if I only appear as vestigal to the commercial Internet, if I appear at all.
sounds more like an enterprise with specific requirements to connect to a limited part of the internet.. this is not the sort of ISP operation that i am working in.
how would you classify such a network? T1, T2, ODDBALL-0, non-Internet-265, ???
enterprise Steve
On Tue, Mar 29, 2005 at 02:23:06AM +0100, Stephen J. Wilcox wrote:
701 is not the most connected, it has only customers and a restrictive set of peers?
Ok, I'm just bored enough to bite. If we're talking about a contest to see who has the most number of directly connected ASNs, I think UU might still win, even with a restrictive set of peers. Taking a look at a count of customer ASNs behind some specific networks of note, I come up with the following (some data a couple weeks out of date, but the gist is the same): Network ASN Count ------- --------- 701 2298 7018 1889 1239 1700 3356 1184 209 1086 174 736 3549 584 3561 566 2914 532 2828 427 6461 301 1299 243 Which begs the question, what is the largest number of ASNs that someone peers with? Patrick? :) Somehow I suspect that 701's customer base (702 and 703 aren't included in the above count BTW) overpower even the most aggressively open of peering policies, in this particular random pointless and arbitrary contest at any rate. -- Richard A Steenbergen <ras@e-gerbil.net> http://www.e-gerbil.net/ras GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)
On Mar 29, 2005, at 1:24 AM, Richard A Steenbergen wrote:
On Tue, Mar 29, 2005 at 02:23:06AM +0100, Stephen J. Wilcox wrote:
701 is not the most connected, it has only customers and a restrictive set of peers?
Ok, I'm just bored enough to bite. If we're talking about a contest to see who has the most number of directly connected ASNs, I think UU might still win, even with a restrictive set of peers.
Taking a look at a count of customer ASNs behind some specific networks of note, I come up with the following (some data a couple weeks out of date, but the gist is the same):
Network ASN Count ------- --------- 701 2298 7018 1889 1239 1700 3356 1184 209 1086 174 736 3549 584 3561 566 2914 532 2828 427 6461 301 1299 243
Which begs the question, what is the largest number of ASNs that someone peers with? Patrick? :) Somehow I suspect that 701's customer base (702 and 703 aren't included in the above count BTW) overpower even the most aggressively open of peering policies, in this particular random pointless and arbitrary contest at any rate.
Of course. There is a difference between "most peers" and "most adjacent ASes". But it is non-trivial to see which of those adjacencies are transit and which are peering. (Nearly impossible if you define such things on Layer 8, but not impossible if you only include which ASes are propagated to which other ASes.) At the end of the day, an AS with a LOT of downstream ASes can always beat a well peered AS - there just aren't that many ASes which peer. -- TTFN, patrick
On Tue, 29 Mar 2005, Richard A Steenbergen wrote:
On Tue, Mar 29, 2005 at 02:23:06AM +0100, Stephen J. Wilcox wrote:
701 is not the most connected, it has only customers and a restrictive set of peers?
Ok, I'm just bored enough to bite.
but not as bored as bill, randy or patrick it would seem :)
If we're talking about a contest to see who has the most number of directly connected ASNs, I think UU might still win, even with a restrictive set of peers.
I didnt think we were, kinda happened.. if peering partners is a compensation for something else its pretty sad ;) Maybe I'm wrong, i checked with renesys and their data has 701 with 5200 adjacencies followed by 1239 with 3500 anyway i care enough to have snipped the data.
Which begs the question, what is the largest number of ASNs that someone peers with? Patrick? :) Somehow I suspect that 701's customer base (702 and 703 aren't included in the above count BTW) overpower even the most aggressively open of peering policies, in this particular random pointless and arbitrary contest at any rate.
so what are we debating again? :) Steve
participants (6)
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bmanning＠vacation.karoshi.com -
John Dupuy -
Patrick W Gilmore -
Randy Bush -
Richard A Steenbergen -
Stephen J. Wilcox