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Trouble Ahead for Internet Routing Tables?
joabj writes: "This article in Light Reading, a fiber optics news page, claims that the Internet's routing tables are ballooning in size and within a couple of years "equipment won't have enough processor power and memory to handle them." The article draws its conclusions from the dramatic increase in the number of BGP routing tables over the last six years and the predicted need for more IP addresses for all those pervasive computing goodies we've been promised."
Why do devices that only really need temporary internet access get permanent IP's? If we didn't have all of these extra devices crowding available IP numbers, perhaps there would be no need to develop a more complex numbering system.
- I don't care if they globalize against free speech. All my best free thoughts are done in my head.
Alright.. so first off, this isn't news. Anyone following the NANOG list knows that the routing table is increasing exponentially with the rest of the internet. There isn't anything that can be done about that, realistically. The aggregation Nazis will scream day and night that they can fix the Internet if you would just let them aggregate things properly. Fine, but that would require a total renumbering of the internet, so it isn't at all possible with IPv4, unless everyone out there really feels like renumbering every machine on their network with a publicly addressable IP. Think about that for a minute. They'll scream that they can do it without renumbering, but they're wrong. The routing table is an intricate mesh of advertisements and if everything was aggregated, nothing would work right. BGP's first method of selection of routes is the longest match rule, whereby when you're choosing a route to pass traffic on, you choose the most specific advertisement, eg choose a class C rather than a class B advertisement. If everything was aggregated into /20 or larger blocks, there would be no practical way to load balance traffic in a multihomed environment (when you have transit through more than one ISP).
;)
And secondly, BGP isn't the cause for the routing table growing, it is the cure. There is no way we would still be using IPv4 without BGP. It saved the internet by introducing classless routing.
The answer to this is simple.. upgrade, upgrade, upgrade. There are routers out there that can handle far more than the internet has to throw at them right now.. it's just that Cisco doesn't make them. Juniper does.. check them out. They built a router off some sweet hardware and BSD. You can type 'start shell' in the router and drop to a BSD shell, and they have the route processor to chew through a routing table many times the size of our current table.
ISPs need to keep up with the growth and upgrade their routers, or they will have problems. Much of the instability of the 'net is due to that now, routers get overloaded and reboot and cause all kinds of churn in the network, which overloads other routers, which reload.. you can see the cascading effect. The ISP I work for had to upgrade all of our older routers to 128m of ram and newer route processors.. if all the ISPs did this, there would be no routing table problems. They just don't want to spend the millions they need to to upgrade their infrastructure, unless the users start screaming. So start screaming at your ISP! (unless it's mine.
//Phizzy
"Most European technology just isn't worth our stealing," -- Former CIA chief James Woolsey, referring to Echelon
Let's go through a number of things that came up here:
sigs are a waste of space
Given that the Internet has undergone a transformation as of late, what with all of the theft of IP and violent imagery it propagates, I am happy about its demise. This ranks right up there with the inevitable heat death of the universe in terms of things that I look forward to.
Possibly, when your Internet (the Vint Cerf crappy one) is finished, Microsoft will invent you a new one. You will all probably hate it of course because they certainly won't permit any misdeeds that you all seem so fond of. Just nice clean fun and information with a little dash of profit for all.
Run along now children, play on your Internet while you still can. When Daddy builds a new one your decaying 386 machines won't be compatible and you'll all have to revert back to your BBS days.
Cunning linguists
Wow, I finally get to disagree with Russ on technical grounds... :-)
I think we do need IPv6 for one crucial reason: mobile support. This is something that's cooked into IPv6, and it's the only right way to solve the problem. With v6 mobility, nodes essentially have two IP addresses - one static, the other dynamic. The advantage of this is that most of the world only has to know the static one to talk to you - your nomadic device is responsible for letting the static server know what your current mobile IP addr is. This keeps the Inernet routing tables from ever having to deal with any of the routes to a particular device - it just points to your static IP (which would be part of a routable superblock), and the local network (or wireless carrier, etc.) handles it from there.
I agree that NAT and superblocks have allowed us to be lazy for a few years too long, but it's critical to recognize that the move to IPv6 will be driven by mobility, not a lack of v4 addresses. This in turn won't happen until people start developing and embedding lean, fast v6 stacks into high-volume mobile consumer devices like cellphones, laptops, and PDAs. As much as I hate to say it, Microsoft may be the only one that can get us kicked off-center here.
Oh, and if you've ever done a massive IP address change for a large corporation (I have), you'll know why it's easier to pull shark's teeth than get those addresses back. Note that even mandating NAT at border routers (which seems reasonable on the surface) still requires all IP addresses to be changed to the "martian networks" (net 10, etc.) to avoid the possibility of collisions with the reclaimed addresses. The costs of this re-addressing are simply too high to expect that IANA could reasonably force any recalamation of IP addresses.
We need IPv6, but not because we're running out of v4 address space...
"The future's good and the present is nothing to sneeze at." - Roblimo's last
There's a problem with route aggreggation, and while bigger providers are more responsible, its still an issue. But lets put gigabytes of memory in perspective, here: my biggest personal box is sporting 512M of ram. Is a few gigs of ram any sort of shock for routers that cost hundreds of thousands of dollars?
It also wouldn't surprise me to see more auto-aggregation being done with spare cpu cycles as the routes propagate, which would probably help.