/25's prefixes announced into global routing table?
Hello all, As the IPv4 space get smaller and smaller, does anyone think we'll see a time when /25's will be accepted for global BGP prefix announcement. The current smallest size is a /24 and generally ok for most people, but the crunch gets tighter, routers continue to have more and more ram will it always be /24 the smallest size? Cheers, Mike -- Michael McConnell WINK Streaming; email: michael@winkstreaming.com phone: +1 312 281-5433 x 7400 cell: +506 8706-2389 skype: wink-michael web: http://winkstreaming.com
On Fri, Jun 21, 2013 at 01:56:02PM -0600, Michael McConnell wrote:
As the IPv4 space get smaller and smaller, does anyone think we'll see a time when /25's will be accepted for global BGP prefix announcement. The current smallest size is a /24 and generally ok for most people, but the crunch gets tighter, routers continue to have more and more ram will it always be /24 the smallest size?
RAM != FIB. The forwarding hardware is generally going to be the limit, and that's going to be painful enough as we approach a half million prefixes. You couldn't even consider such a thing until after that pain point. --msa
Majdi S. Abbas wrote:
On Fri, Jun 21, 2013 at 01:56:02PM -0600, Michael McConnell wrote:
As the IPv4 space get smaller and smaller, does anyone think we'll see a time when /25's will be accepted for global BGP prefix announcement. The current smallest size is a /24 and generally ok for most people, but the crunch gets tighter, routers continue to have more and more ram will it always be /24 the smallest size?
RAM != FIB.
For /24, cheap 16M entry SRAM == FIB
The forwarding hardware is generally going to be the limit, and that's going to be painful enough as we approach a half million prefixes.
True. And that's why we must avoid IPv6. Masataka Ohta
The forwarding hardware is generally going to be the limit, and that's going to be painful enough as we approach a half million prefixes.
True. And that's why we must avoid IPv6.
Masataka Ohta
Great comment. :D -- Michael McConnell WINK Streaming; email: michael@winkstreaming.com phone: +1 312 281-5433 x 7400 cell: +506 8706-2389 skype: wink-michael web: http://winkstreaming.com
On 06/22/2013 12:44 AM, Owen DeLong wrote:
The forwarding hardware is generally going to be the limit, and that's going to be painful enough as we approach a half million prefixes.
True. And that's why we must avoid IPv6.
This is not only wrong, it makes no sense whatsoever.
So here's a question: has anyone done any musings/reasearch on how big of a global IPv6 table we could expect given current policies if IPv6 were as widely deployed and used as IPv4 (or if IPv4 didn't exist)? -- Brandon Martin
On Jun 22, 2013, at 7:19 AM, Brandon Martin <lists.nanog@monmotha.net> wrote:
On 06/22/2013 12:44 AM, Owen DeLong wrote:
The forwarding hardware is generally going to be the limit, and that's going to be painful enough as we approach a half million prefixes.
True. And that's why we must avoid IPv6.
This is not only wrong, it makes no sense whatsoever.
So here's a question: has anyone done any musings/reasearch on how big of a global IPv6 table we could expect given current policies if IPv6 were as widely deployed and used as IPv4 (or if IPv4 didn't exist)? -- Brandon Martin
Yes… It will probably settle out somewhere around 100-125K routes. Owen
RFC 3587 - IPv6 Global Unicast Address Format On Jun 22, 2013 6:50 AM, "John Curran" <jcurran@istaff.org> wrote:
On Jun 22, 2013, at 1:45 AM, Owen DeLong <owen@delong.com> wrote:
Yes… It will probably settle out somewhere around 100-125K routes.
Owen -
Can you elaborate some on this estimate? (i.e. what approximations and/or assumptions are you using to reach this number?)
Thanks! /John
On Jun 22, 2013, at 12:48 PM, John Curran <jcurran@istaff.org> wrote:
On Jun 22, 2013, at 1:45 AM, Owen DeLong <owen@delong.com> wrote:
Yes… It will probably settle out somewhere around 100-125K routes.
Owen -
Can you elaborate some on this estimate? (i.e. what approximations and/or assumptions are you using to reach this number?)
Thanks! /John
Looking at the number of autonomous systems in the IPv6 routing table and the total number of routes, it looks like it will shake out somewhere in the neighborhood of 3-5 prefixes/ASN. Since there are ~35,000 unique ASNs in the IPv4 table, I figured simple multiplication provided as good an estimate as any at this early time. Owen
On 22-06-13 17:30, Owen DeLong wrote:
Looking at the number of autonomous systems in the IPv6 routing table and the total number of routes, it looks like it will shake out somewhere in the neighborhood of 3-5 prefixes/ASN. Since there are ~35,000 unique ASNs in the IPv4 table, I figured simple multiplication provided as good an estimate as any at this early time.
Deaggregating of IPv4 announcements is done for traffic engineering and to fight ddoses (just the attacked /24 stops being announced to internet). I think some people will just copy their v4 habits into v6 and then we might have explosion of /48's. I wouldn't be so sure about just 3-5 prefixes/ASN. -- Grzegorz Janoszka
On Jun 22, 2013, at 10:16 PM, Grzegorz Janoszka <Grzegorz@Janoszka.pl> wrote:
On 22-06-13 17:30, Owen DeLong wrote:
Looking at the number of autonomous systems in the IPv6 routing table and the total number of routes, it looks like it will shake out somewhere in the neighborhood of 3-5 prefixes/ASN. Since there are ~35,000 unique ASNs in the IPv4 table, I figured simple multiplication provided as good an estimate as any at this early time.
Deaggregating of IPv4 announcements is done for traffic engineering and to fight ddoses (just the attacked /24 stops being announced to internet). I think some people will just copy their v4 habits into v6 and then we might have explosion of /48's. I wouldn't be so sure about just 3-5 prefixes/ASN.
Some ASNs will be more, some will be less. Since there's already some DDOS and such on IPv6, I would expect the current prefix table to include a reasonable example of all of the behaviors you describe. Owen
On Jun 22, 2013, at 16:16 , Grzegorz Janoszka <Grzegorz@Janoszka.pl> wrote:
On 22-06-13 17:30, Owen DeLong wrote:
Looking at the number of autonomous systems in the IPv6 routing table and the total number of routes, it looks like it will shake out somewhere in the neighborhood of 3-5 prefixes/ASN. Since there are ~35,000 unique ASNs in the IPv4 table, I figured simple multiplication provided as good an estimate as any at this early time.
Deaggregating of IPv4 announcements is done for traffic engineering and to fight ddoses (just the attacked /24 stops being announced to internet). I think some people will just copy their v4 habits into v6 and then we might have explosion of /48's. I wouldn't be so sure about just 3-5 prefixes/ASN.
Not that many people are de-aggregating in anticipation of the DDoS. Temporary de-agg during DDoS is not relevant to discussions on global table sizes. -- TTFN, patrick
And this presentation by Geoff Huston: http://iepg.org/2011-11-ietf82/2011-11-13-bgp2011.pdf Regards, as On 6/22/13 11:48 AM, John Curran wrote:
On Jun 22, 2013, at 1:45 AM, Owen DeLong <owen@delong.com> wrote:
Yes… It will probably settle out somewhere around 100-125K routes. Owen -
Can you elaborate some on this estimate? (i.e. what approximations and/or assumptions are you using to reach this number?)
Thanks! /John
Le 25/06/2013 11:43, Arturo Servin a écrit :
And this presentation by Geoff Huston:
Thanks ! Funny thing is, the IPv4 table projection looks accurate for now. Does it seem plausible to establish a backpressure model over a longer period now we have some more data about new allocation policies and general behavior ? -- Jérôme Nicolle 06 19 31 27 14
On Sat, Jun 22, 2013 at 12:44 AM, Owen DeLong <owen@delong.com> wrote:
The forwarding hardware is generally going to be the limit, and that's going to be painful enough as we approach a half million prefixes.
True. And that's why we must avoid IPv6.
This is not only wrong, it makes no sense whatsoever.
Neither did the first part of his statement. Gigabit srams are neither particularly cheap nor particularly better suited to implementing a FIB than plain old dram. On Sat, Jun 22, 2013 at 1:19 AM, Brandon Martin <lists.nanog@monmotha.net> wrote:
So here's a question: has anyone done any musings/reasearch on how big of a global IPv6 table we could expect given current policies if IPv6 were as widely deployed and used as IPv4 (or if IPv4 didn't exist)?
Too soon to tell. On the one hand, we shouldn't have the registry-driven fragmentation. They're trying hard to allocate enough addresses for all foreseeable demand, not just near term, and they're leaving space to bump the netmask for the next request when it comes. They're also selecting policies which discourage multihomed end users from breaking up their ISP's block instead of getting their own. On the other side of the hump with IPv4 in decline, both of these should reduce the total number of announcements chosen by each organization. On the other hand, IPv6 addresses consume upwards of 4 times the bits in the FIB. On the fence, the tools for traffic engineering have not changed, the registries are making no attempt to allocate in a manner that facilitates TE filtering, and there's still no better way than a BGP announcement for an end-user to multihome. Number transfers for mergers, acquisitions and divestitures, and renumbering in general suffer from all the same ailments they do in IPv4. At 128 bits instead of 32 bits, all of these factors should impact IPv6 the in same manner they have impacted IPv4. 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 forwarding hardware is generally going to be the limit, and that's going to be painful enough as we approach a half million prefixes.
I would expect that we might finally see some pushback against networks that announce lots of disaggregated prefixes. The current CIDR report notes that the 400K prefixes could be 260K if aggregated. I realize it's not quite that simple due to issues of longer prefixes taking precedence over shorter ones, but it is my impression that there's a lot of sloppiness.
John Levine wrote:
I realize it's not quite that simple due to issues of longer prefixes taking precedence over shorter ones, but it is my impression that there's a lot of sloppiness.
16M /24 is just a cheap 16M entry SRAM. However, 16M /32 means 4G entry SRAM or 16M entry CAM. 16M entry with /40 or /48 prefix means 16M entry CAM, which is hard, which is why IPv6 is hard. Masataka Ohta
On 21-06-13 21:56, Michael McConnell wrote:
As the IPv4 space get smaller and smaller, does anyone think we'll see a time when /25's will be accepted for global BGP prefix announcement. The current smallest size is a /24 and generally ok for most people, but the crunch gets tighter, routers continue to have more and more ram will it always be /24 the smallest size?
As the fragmentation will progress and we will be closing to the magic limit of 500.000, people will filter out /24 and then /23 and so on. Back to static (default) routing! -- Grzegorz Janoszka
As the IPv4 space get smaller and smaller, does anyone think we'll see a time when /25's will be accepted for global BGP prefix announcement. The current smallest size is a /24 and generally ok for most people, but the crunch gets tighter, routers continue to have more and more ram will it always be /24 the smallest size? As the fragmentation will progress and we will be closing to the magic
On 21-06-13 21:56, Michael McConnell wrote: limit of 500.000, people will filter out /24 and then /23 and so on. Back to static (default) routing! 500k is imho no different than 250k 128k 100k. Some devices are going to fall off the applecart. some folks will engage in heroic measures to
On 6/21/13 2:15 PM, Grzegorz Janoszka wrote: police their fib size and the world will move on. million route and 2 million route fib platforms abound. if we cross the million mark in 10 years we're fine. if we cross it in 2 (which doesn't seem likely) then we have a problem. the v6 table imho is the one to watch.
Quite the opposite. As the technical limitations of the routing gear are reached, shorter and shorter prefixes will be tolerated until IPv4 is utterly unusable if we try to stay on IPv4 that long. Owen On Jun 21, 2013, at 9:56 PM, Michael McConnell <michael@winkstreaming.com> wrote:
Hello all,
As the IPv4 space get smaller and smaller, does anyone think we'll see a time when /25's will be accepted for global BGP prefix announcement. The current smallest size is a /24 and generally ok for most people, but the crunch gets tighter, routers continue to have more and more ram will it always be /24 the smallest size?
Cheers, Mike
--
Michael McConnell WINK Streaming; email: michael@winkstreaming.com phone: +1 312 281-5433 x 7400 cell: +506 8706-2389 skype: wink-michael web: http://winkstreaming.com
On Fri, Jun 21, 2013 at 3:56 PM, Michael McConnell <michael@winkstreaming.com> wrote:
As the IPv4 space get smaller and smaller, does anyone think we'll see a time when /25's will be accepted for global BGP prefix announcement. The current smallest size is a /24 and generally ok for most people, but the crunch gets tighter, routers continue to have more and more ram will it always be /24 the smallest size?
No. 1. Too many ASes whose operators are a part of too many cultures and speak too many languages apply a blind filter at /24. Too hard to change. 2. TCAM != RAM However.... It is possible for a tunnel provider to: 1. Draw a covering route in to a well chosen set of data centers, 2. Set up a nice redundant set of tunnels from each data center to each of its customers' Internet links, 3. Accept smaller-than-/24 routes at a higher priority than the tunnels from its peers where those routes originate from the customers to whom it assigned those addresses 4. Help the customers negotiate with the specific handful of ISPs that operate the paths between them so that they'll accept the sourced packets natively and propagate the smaller-than-/24 route within their system. It hasn't been done with any regularity, but it's technically feasible, can be implemented within a few percent of optimal routing and resilience and requires cooperation from few enough parties (all of them directly paid) that it could happen if the economics were right. On Fri, Jun 21, 2013 at 5:15 PM, Grzegorz Janoszka <Grzegorz@janoszka.pl> wrote:
As the fragmentation will progress and we will be closing to the magic limit of 500.000, people will filter out /24 and then /23 and so on. Back to static (default) routing!
Don't bet heavy on that either. Many if not most of the Internet's critical resources (think: DNS roots) sit within /24 announcements. Incautious filtering shoots oneself in the foot. 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 6/21/13, Michael McConnell <michael@winkstreaming.com> wrote:
Hello all, As the IPv4 space get smaller and smaller, does anyone think we'll see a time when /25's will be accepted for global BGP prefix announcement. The
I am confident there are providers that will accept /25s from some of their customer(s) or peer(s); either due to negotiations with some of their customer(s); or as a result of ignorance or administrative error (failing to reject /25s, and not realizing it).
current smallest size is a /24 and generally ok for most people, but the
Well, current smallest size intended to be accepted is /24 for many major providers. Some will be more restrictive. /24 is useful as a rule of thumb but not "an exact size" that every network allows. Further address fragmentation will eventually demand that networks become more restrictive, OR that the underlying protocol and hardware gets redesigned; which again, leads to netwroks becoming more restrictive, to avoid spending $$$ on hardware, software, and config upgrades.
crunch gets tighter, routers continue to have more and more ram will it always be /24 the smallest size?
Cheers, Mike -- -JH
Hello, On Fri, 21 Jun 2013 13:56:02 -0600 Michael McConnell <michael@winkstreaming.com> wrote:
As the IPv4 space get smaller and smaller, does anyone think we'll see a time when /25's will be accepted for global BGP prefix announcement. The current smallest size is a /24 and generally ok for most people, but the crunch gets tighter, routers continue to have more and more ram will it always be /24 the smallest size?
Well, /25 are already in the routing table. I can even find a few /26 !! rtr-01.PAR#sh ip b | i /26 *>i193.41.227.128/26 *>i193.41.227.192/26 *>i194.149.243.64/26 Paul -- TelcoTV Awards 2011 - Witbe winner in "Innovation in Test & Measurement" Paul Rolland E-Mail : rol(at)witbe.net CTO - Witbe.net SA Tel. +33 (0)1 47 67 77 77 Les Collines de l'Arche Fax. +33 (0)1 47 67 77 99 F-92057 Paris La Defense RIPE : PR12-RIPE LinkedIn : http://www.linkedin.com/in/paulrolland Skype : rollandpaul "I worry about my child and the Internet all the time, even though she's too young to have logged on yet. Here's what I worry about. I worry that 10 or 15 years from now, she will come to me and say 'Daddy, where were you when they took freedom of the press away from the Internet?'" --Mike Godwin, Electronic Frontier Foundation
I'm not going to even ask or look at who is accepting /26's -jim On Mon, Jun 24, 2013 at 2:29 PM, Paul Rolland <rol@witbe.net> wrote:
Hello,
On Fri, 21 Jun 2013 13:56:02 -0600 Michael McConnell <michael@winkstreaming.com> wrote:
As the IPv4 space get smaller and smaller, does anyone think we'll see a time when /25's will be accepted for global BGP prefix announcement. The current smallest size is a /24 and generally ok for most people, but the crunch gets tighter, routers continue to have more and more ram will it always be /24 the smallest size?
Well, /25 are already in the routing table. I can even find a few /26 !!
rtr-01.PAR#sh ip b | i /26 *>i193.41.227.128/26 *>i193.41.227.192/26 *>i194.149.243.64/26
Paul
-- TelcoTV Awards 2011 - Witbe winner in "Innovation in Test & Measurement"
Paul Rolland E-Mail : rol(at)witbe.net CTO - Witbe.net SA Tel. +33 (0)1 47 67 77 77 Les Collines de l'Arche Fax. +33 (0)1 47 67 77 99 F-92057 Paris La Defense RIPE : PR12-RIPE
LinkedIn : http://www.linkedin.com/in/paulrolland Skype : rollandpaul
"I worry about my child and the Internet all the time, even though she's too young to have logged on yet. Here's what I worry about. I worry that 10 or 15 years from now, she will come to me and say 'Daddy, where were you when they took freedom of the press away from the Internet?'" --Mike Godwin, Electronic Frontier Foundation
On Jun 24, 2013, at 13:29 , Paul Rolland (ポール・ロラン) <rol@witbe.net> wrote:
On Fri, 21 Jun 2013 13:56:02 -0600 Michael McConnell <michael@winkstreaming.com> wrote:
As the IPv4 space get smaller and smaller, does anyone think we'll see a time when /25's will be accepted for global BGP prefix announcement. The current smallest size is a /24 and generally ok for most people, but the crunch gets tighter, routers continue to have more and more ram will it always be /24 the smallest size?
Well, /25 are already in the routing table. I can even find a few /26 !!
rtr-01.PAR#sh ip b | i /26 *>i193.41.227.128/26 *>i193.41.227.192/26 *>i194.149.243.64/26
The question was when will we see /25s in the GLOBAL routing table. Despite the very un-well defined definition for "global routing table", I'm going to assuming something similar to the DFZ, or the set of prefixes which is seen in all (most of?) the transit-free networks[*]. Given that definition, there are exactly zero /25s in the GRT (DFZ). And unlikely to be for a while. Whether "a while" is "next 12 months" or "several years" is something I am very specifically choosing not to answer. -- TTFN, patrick [*] Don't you hate the term "tier one" these days? It doesn't mean what it used to mean (i.e. _settlement free_ peering with all other tier one networks). And given that there are non-transit-free networks with more [traffic|revenue|customers|$WHATEVER] than some transit free networks, I prefer to not use the term.
How do I convince my peers to accept /25's ?? :D -- Michael McConnell WINK Streaming; email: michael@winkstreaming.com phone: +1 312 281-5433 x 7400 cell: +506 8706-2389 skype: wink-michael web: http://winkstreaming.com On Jun 24, 2013, at 12:53 PM, Patrick W. Gilmore <patrick@ianai.net> wrote:
On Jun 24, 2013, at 13:29 , Paul Rolland (ポール・ロラン) <rol@witbe.net> wrote:
On Fri, 21 Jun 2013 13:56:02 -0600 Michael McConnell <michael@winkstreaming.com> wrote:
As the IPv4 space get smaller and smaller, does anyone think we'll see a time when /25's will be accepted for global BGP prefix announcement. The current smallest size is a /24 and generally ok for most people, but the crunch gets tighter, routers continue to have more and more ram will it always be /24 the smallest size?
Well, /25 are already in the routing table. I can even find a few /26 !!
rtr-01.PAR#sh ip b | i /26 *>i193.41.227.128/26 *>i193.41.227.192/26 *>i194.149.243.64/26
The question was when will we see /25s in the GLOBAL routing table. Despite the very un-well defined definition for "global routing table", I'm going to assuming something similar to the DFZ, or the set of prefixes which is seen in all (most of?) the transit-free networks[*].
Given that definition, there are exactly zero /25s in the GRT (DFZ). And unlikely to be for a while. Whether "a while" is "next 12 months" or "several years" is something I am very specifically choosing not to answer.
-- TTFN, patrick
[*] Don't you hate the term "tier one" these days? It doesn't mean what it used to mean (i.e. _settlement free_ peering with all other tier one networks). And given that there are non-transit-free networks with more [traffic|revenue|customers|$WHATEVER] than some transit free networks, I prefer to not use the term.
On 6/24/13, Michael McConnell <michael@winkstreaming.com> wrote:
How do I convince my peers to accept /25's ?? :D
1. Ask. As in support requests; report as connectivity defect that your /25s are not propagated. 2. Contract negotiation. 3. More cash. 4. Replace peers/upstreams with competing providers as necessary, until you find one where one or more of the above will suffice.
-- Michael McConnell -- -JH
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Le 24/06/2013 19:29, Paul Rolland (???????) a écrit :
Well, /25 are already in the routing table. I can even find a few /26 !!
So did I : http://lg.ring.nlnog.net/adv/lg02+lg01/ipv4?q=where%20net.len=26 But guess what ? They didn't stop there ! http://lg.ring.nlnog.net/adv/lg02+lg01/ipv4?q=where%20net.len=27 Want some more ? Hey, take some /28 ! http://lg.ring.nlnog.net/adv/lg02+lg01/ipv4?q=where%20net.len=28 And the list goes on... Up to /32 !! http://lg.ring.nlnog.net/adv/lg02+lg01/ipv4?q=where%20net.len=32 Guess you could actually multi-home a /32 now... - -- Jérôme Nicolle +33 6 19 31 27 14 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlHIsfsACgkQbt+nwQamihvQ8gCdFBEmNiK6XJvLy770bFG/nPa0 IwYAn3cWI4rul5eNvW2t944vOgkLhof1 =NCMg -----END PGP SIGNATURE-----
participants (18)
-
Arturo Servin -
Brandon Martin -
Grzegorz Janoszka -
jim deleskie -
Jimmy Hess -
joel jaeggli -
John Curran -
John Levine -
Jérôme Nicolle -
Majdi S. Abbas -
Masataka Ohta -
Michael McConnell -
Owen DeLong -
Patrick W. Gilmore -
Paul Rolland -
shawn wilson -
Valdis.Kletnieks＠vt.edu -
William Herrin