RE: Criteria for initial PA Allocation
Hi, On Tuesday, May 22, 2001 15:58, Gert Doering, Netmaster [SMTP:netmaster@space.net] wrote:
Hi,
(originally I did not really want to participate in this discussion, as much of it has already been said in the last LIR-WG meeting).
One thing got me thinking,though:
On Tue, May 22, 2001 at 02:16:32PM +0100, Carlos Friacas wrote:
/22 is a much more reasonable value by my view...
Be careful what you are asking for.
If we assume that minimum allocation size will go down to a /22, and further assume that one fourth of the full IPv4 address range will subsequently be handed out *and announced* as /22's, this means we will see ( 1/4 * 2^22 ) = 1048576 /22's announced in the global BGP table. That's over a million BGP routing table entries.
I agree this is a concern, but it's always better then having the same amount of /20's in the table. I agree that we have to guard that potential 'real' LIR's do not start off with a /22, but that is also already achieved by reserving contiguous address space for a certain amount of time. The point is, would the NCC also decrease this reservation mechanism?
This will have a significant effect on BGP routing stability and also on the costs of global routing - you need a Gig of RAM in all the BGP routers (on distributed architectures, more than that). The CPU power required to handle a flap of a major line in a timely fashion (to keep BGP convergence times low) will be horrendous.
Also, it can be assumed that in this case, the global topology will become complex enough so that most of the time many of the smaller ASes won't be reachable anyway due to problems "on the way".
I think this is something I do NOT want to see.
So, what is my conclusion? I estimate that while IPv4 address exhaustion is going to be a problem (which IPv6 will solve), the routing topology will cause major problems *sooner* than IPv4 runs out, and we should do something against this. By this, I mean:
IPv6 solves the exhaustion problem, but does it solve the multihoming problem? You would still have a lot of small companies wanting 'routable' address space. Getting PA address space makes you dependable on the routing table of at least one provider and thus doesn't guarantee you redundancy.
- strongly encourage people to renumber from historic PI space to PA space from their ISPs network block (and return the PI space to the RIRs, to be aggregated)
- stop handing out PI space
- discourage "end users" from using multihoming with globally visible address space (there are other ways, like "get multiple uplinks to different POPs of the same ISP, and have them sign a SLA that will get you 99.9% reachability or money back").
That is not really the same. For many companies, an outage of a few days can mean that they are out of business. Having your money back is then your least concern. The fact is that disasters do happen to every ISP once in a while and a lot of company's want to protect themselves from that. I don't think you really can discourage that.
- discourage people from becoming LIR if that's only to get "portable" address space, with no intention of handing PA space out to customers.
That's nice, but you'll have to be able to offer them a good alternative. There are a few good alternatives (like NAT), but not all of these are workable for everybody.
Yes, this might sound a bit harsh, but I'm *really* worried about routeability and reachability of anything in the next couple of years.
I agree it can create huge problems and we have to be careful, but the fact is multihoming is a huge dilemma for a lot of small company's (small of course in the sense of size of IP address space). Regards, Bert van Hogeloon
Now go and flame me... :-)
Gert Doering -- NetMaster -- SpaceNet AG Mail: netmaster@Space.Net Joseph-Dollinger-Bogen 14 Tel : +49-89-32356-0 80807 Muenchen Fax : +49-89-32356-299
Hi, On Tue, May 22, 2001 at 05:11:10PM +0200, Hogeloon, Bert van wrote:
If we assume that minimum allocation size will go down to a /22, and further assume that one fourth of the full IPv4 address range will subsequently be handed out *and announced* as /22's, this means we will see ( 1/4 * 2^22 ) = 1048576 /22's announced in the global BGP table. That's over a million BGP routing table entries.
I agree this is a concern, but it's always better then having the same amount of /20's in the table.
With /20's, again assuming one fourth of the total IPv4 range being announced as /20, you'll only get 262144 prefixes, which is a LOT less (you can't get one million /20's due to the limited amount of IPv4 addresses). [..]
So, what is my conclusion? I estimate that while IPv4 address exhaustion is going to be a problem (which IPv6 will solve), the routing topology will cause major problems *sooner* than IPv4 runs out, and we should do something against this. By this, I mean:
IPv6 solves the exhaustion problem, but does it solve the multihoming problem?
No, which is exactly what I wrote. I think the emphasis today should not be on "conservation of the last single IPv4 address" but on "develop something that will scale routing to a vastly larger address space".
You would still have a lot of small companies wanting 'routable' address space. Getting PA address space makes you dependable on the routing table of at least one provider and thus doesn't guarantee you redundancy.
Getting PI space guarantees that you will NOT be reachable by some parts of the internet today, and it's likely that you won't be reachable by larger parts in a few years. Having PI space doesn't guarantee you *anything*, especially not "redundancy", or "reachability". In this multihoming discussion, one should not overlook what people hope to gain by doing it. Most of them want "99.9999 per cent internet availability". Multihoming with globally visible address space might sound like a good way to achieve this, but it might not be the best. All it means is that you need someone (expensive) to maintain your routers, your BGP setup, and tune all the lose ends if something isn't routed optimally. And if one of your upstream providers really messes things up (like blackholing your traffic accidently), you've lost connectivity to a large part of the net nonetheless. So one of the issues is "how can we improve people's internet connection's reliability without multihoming with a globally visible address space". Having multiple upstreams with multile PA assignements and doing DNS round robin (with a low TTL) is one way. Having many lines to one upstream ISP - to different POPs - and a 99.99999% guaranteed SLA is another way.
- strongly encourage people to renumber from historic PI space to PA space from their ISPs network block (and return the PI space to the RIRs, to be aggregated)
- stop handing out PI space
- discourage "end users" from using multihoming with globally visible address space (there are other ways, like "get multiple uplinks to different POPs of the same ISP, and have them sign a SLA that will get you 99.9% reachability or money back").
That is not really the same. For many companies, an outage of a few days can mean that they are out of business. Having your money back is then your least concern.
So how do you guarantee "you can reach 99% of the Internet 99% of the time" if you do BGP multihoming? You can't. For those companies, having redundant computing centres, connected to different ISPs, and using different address space (PA) might actually lead to better reliability...
The fact is that disasters do happen to every ISP once in a while and a lot of company's want to protect themselves from that. I don't think you really can discourage that.
While I can understand why people want this, it means that the chances for desasters actually increase a lot *due* to all those people. Like "routers crashing due to RAM overflow". Like "bogon routes announced all over the world due to incorrect filters", and so on.
- discourage people from becoming LIR if that's only to get "portable" address space, with no intention of handing PA space out to customers.
That's nice, but you'll have to be able to offer them a good alternative.
Why? Just because that's the way it has always been? (Not being overly cooperative today :-) ) [..] Gert Doering -- NetMaster -- SpaceNet AG Mail: netmaster@Space.Net Joseph-Dollinger-Bogen 14 Tel : +49-89-32356-0 80807 Muenchen Fax : +49-89-32356-299
On Tue, 22 May 2001, Gert Doering, Netmaster wrote:
While I can understand why people want this, it means that the chances for desasters actually increase a lot *due* to all those people. Like "routers crashing due to RAM overflow". Like "bogon routes announced all over the world due to incorrect filters", and so on.
- discourage people from becoming LIR if that's only to get "portable" address space, with no intention of handing PA space out to customers.
That's nice, but you'll have to be able to offer them a good alternative.
Why? Just because that's the way it has always been? (Not being overly cooperative today :-) )
Well, i tend to agree more with Gert... We reduce portability in order to gain on aggregability and getting the global routing table as shorter as we can... Perhaps if the "lazy people" could be forced to start using all the alternatives to valid IP addresses we could get a greater improve... Lack of knowledge about CIDR is also a big problem... i see some things today that i really shouldnt see... I know that they ("dumb & lazy people") are getting the money in, but if it could be explained to them that they will have to "fund" even more because the global routing table is growing the way it is... they could get convinced... (but anyway, the router manufacturers wouldnt like this idea! ;-) ) I still didnt see one of my questions answered... is there anyway of sweeping through ASNs to find the people that have them, and dont make a "valid" use of those ASNs ? (Im thinking about those people that only have one BGP peering, and those cases of companies buying others and just maintaining 2 or more ASNs...) And if someone looses their ASN, what the problem about getting a new one later if it can be properly justified ??? One other thing i would like to see would be an "European Initiative to give back PIs space to ARIN" :-) I got an OK from RIPE to exchange "X" PI space for "X" PA space from my LIR, but this hasnt solved the whole lot of my cases... but then again... my clients are too complex ! :-)
[..]
Gert Doering -- NetMaster -- SpaceNet AG Mail: netmaster@Space.Net Joseph-Dollinger-Bogen 14 Tel : +49-89-32356-0 80807 Muenchen Fax : +49-89-32356-299
Thanks for your patience. Regards, ./Carlos "Networking is fun!" ------------------- <cfriacas@fccn.pt>, CMF8-RIPE, Wide Area Network WorkGroup http://www.fccn.pt F.C.C.N. - Fundacao para a Computacao Cientifica Nacional fax: +351 218472167
participants (3)
-
Carlos Friacas -
Gert Doering, Netmaster -
Hogeloon, Bert van