[routing-wg]On Vince's talk

Hello;

On Oct 5, 2006, at 8:50 AM, Iljitsch van Beijnum wrote:

> On 4-okt-2006, at 16:10, Joao Damas wrote:
>
>> In addition, while watching Vince's presentation, and seeing how  
>> the little IPv6 would contribute to the total sum of routes one  
>> would be seeing announced to the Internet (internal routes are  
>> each ISP's problem in this context, to some extent) I was  
>> wondering what would actually happen towards the time around which  
>> *new* IPv4 addresses would become scarce and people are forced to  
>> change the way IPv4 is used (eg, by splitting current allocations  
>> and trading those smaller chunks).
>
> Well, obviously that wouldn't be good. The question is how bad it  
> would get? I think the current trends in routing table growth would  
> continue more or less the same as before in the years immediately  
> following the depletion of the free IPv4 address pools, as the  
> underlying need remains the same and people will still find a way  
> to get an address block, even though they probably won't get it  
> from a RIR and it's going to be smaller than they'd like.
>
> (Although the RIRs will get address space back from people that  
> don't need it anymore, so they'll likely be able to continue to  
> give out small blocks. 90% of all allocations are responsible for  
> only 10% of the address space = less than a /8 a year.)
>
>> Then the question might become, what would the mess look like if  
>> there is no IPv6 deployment? and does the picture Vince hinted at  
>> become any worse in the absence of IPv6 deployment, even with the  
>> less than perfect routing solutions currently available?
>
> Ah, but there already is IPv6 deployment. I use it every day. A  
> quarter or so of the traffic generated at RIPE meetings is IPv6.  
> 0.1% of all traffic flowing over the AMS-IX is IPv6. Going out on a  
> limb here, that figure suggests that 3% of all systems exchanging  
> traffic over the AMS-IX are IPv6-enabled. Logic: for 97% of all  
> systems, 100% of their traffic is IPv4, but for the other 3%, 97%  
> would be IPv4 and 3% IPv6, for a total of 0.97 + 0.03 * 0.97 =  
> 0,999% of all traffic being IPv4. There is probably something else  
> that generates the majority of the 130 Mbps of IPv6 traffic on AMS- 
> IX, but it's still an average of 130 Mbps, which is probably more  
> than the IPv4 traffic 15 years ago.

I cannot resist pointing out here that

2.2 % of the ASNs and 4.2% of the IPv4 address blocks are multicast  
enabled, as seen from here
http://www.multicasttech.com/status/

and
~ 2% of the Abilene backbone netflow traffic is IPv4 ASM multicast,
as seen here
http://netflow.internet2.edu/weekly/longit/perc-multicast-octets.png

Regards
Marshall

>
> Coming back to routing: seeing recent developments in address  
> policies and given the notion that the same people who made a mess  
> of the IPv4 routing table will be running IPv6 at some point, I  
> think the basic problem will remain the same. The routing table for  
> IPv6 + IPv4 will probably be quite similar to the one for IPv4  
> without IPv6, at least until either the effects of massive IPv4  
> scarcity or retiring of IPv4 in favor of IPv6 will/would become  
> noticeable, either of which will be a long way off.
>
> Last year the routing table increased by 16%. That gives us (in  
> thousands):
>
> 2007 ~ 210
> 2008 ~ 240
> 2009 ~ 280
> 2010 ~ 325
> 2011 ~ 375
> 2012 ~ 435
> 2013 ~ 500
>
> So if I were to buy an expensive router I would certainly want it  
> to be able to carry half a million prefixes in its FIB table, and  
> have enough RP memory for several million BGP table entries.  
> Linecards with 512 MB RAM can be had today, and assuming that a FIB  
> entry is less than a kilobyte seems reasonable but of course  
> assumptions are dangerous. The problem is probably the jump to 64  
> bit RP CPUs because the 2 gigabyte barrier will be a problem in the  
> forseeable future.
>
> I agree that internal routes can be a problem in large ASes, but  
> that's just a question of proper engineering: unlike in inter- 
> domain routing, in internal routing there are aggregation  
> mechanisms that can be made to work effectively.
>
> I would be nice if we could create similar mechanisms for BGP. The  
> whole notion that when someone in Nairobi starts announcing a bunch  
> of more specifics to his neighbor, EVERY BGP router in the world  
> must process these extra prefixes and then search through them for  
> every packet that is forwarded, is seriously broken.
>
> As for my comments during Vince's talk:
>
> (Ugh, I think the APNIC website has an IPv6 PMTUD problem, pages  
> take forever to load... Works better with javascript disabled.)
>
> http://www.apnic.net/news/hot-topics/index.html#ip-addressing
>