nanog mailing list archives
Re: Deploying IPv6 in a datacenter (Was: Awful quiet?)
From: Kevin Day <toasty () dragondata com>
Date: Wed, 21 Dec 2005 19:59:15 -0600
On Dec 21, 2005, at 4:18 PM, Daniel Roesen wrote:
1) IPv6 on the internet overall seems a bit unreliable at the moment. Entire /32's disappear and reappear, gone for days at a time.That's certainly true for people not doing it "in production". But thatain't a problem as they aren't doing it... in production. :-)
We had a case where a somewhat decent sized provider that was actually using IPv6 accidentally stopped announcing their space without realizing it. After a couple of days of waiting for them to fix it, I emailed their NOC and got the impression that I was the first to notice they had killed IPv6.
The most common path over IPv6 from the US to Europe is US->JP->US- >EU.Sorry, but that's not true anymore on grand scale. That might still be valid for some exceptionally bad IPv6 providers who still "do it 6bonestyle". Fortunately, those don't play any too significant role anymore inglobal IPv6 routing (which was hard work to achieve).
I admit, my experiences are with only a tiny number of users, so I may have just had bad luck. But, I had trouble finding any of our IPv6 guinea pigs that didn't take a perceptibly slower route to us over 6 than they do for 4. (50-100ms)
I realize this may be specific to our connection itself, but browsing looking glasses seems to back up that it's not just us.That'd suprise me. Could you give examples?
Right now, I can't remember, this was a couple of months ago now... But next time I encounter one, I'll drop you an email.
5) Our DNS software(djbdns) supports IPv6, kind of. WIth patches you can enter AAAA records, but only by entering 32 digit hexadecimal numbers with no colons or abbreviations. We were never able to get it to respond to queries over IPv6, so of all our DNS is still IPv4.Then stop using incomplete and cumbersome software from authors with strong religious believes and a disconnection from any technological advances of the last $many years. :-) "Use the right tools for the job".
I don't doubt that there are better tools for IPv6 DNS, but we were already using djbdns for a couple of reasons and I didn't want to undergo a switch to something else JUST to add AAAA records when what we had was working well enough for us. I wasn't trying to document how to do IPv6 right, just what problems we hit when we tried to switch to IPv6 with no thought to IPv6 being done beforehand.
10) Smaller than normal MTUs seem much more common on IPv6, and it is exposing PMTUD breakage on a lot of people's networks.It is, but we have tracked down most of them... at least the ones we noticed. I don't experience PMTUD problems anymore since long... the last one is prolly over half a year ago. And I use IPv6 on all my servers, desktops and laptop. :-)
Our test network was running through a GRE tunnel inside an IPIP tunnel, so our MTU was abnormally tiny. I'm guessing that hit some people with PMTUD problems that didn't normally see them because they had a short MTU to start with.
11) Almost without fail, the path an IPv6 user takes to reach us (and vice-versa) is less optimal than the IPv4 route. Users are being penalized for turning on IPv6, since they have no way to fall back to IPv4 on a site-by-site basis when using a web browser.That is indeed a problem. How big the penalty is, depends heavily onyour choice of upstream provider(s). The isle of sanity gets bigger andbigger, and networks with bad IPv6 connectivity become more seldom (relatively).
Out of all of our transit providers, only one could sell us IPv6 transit(not faulting those who don't yet). Out of 100+ peering connections, only 2 wanted to do IPv6 peering. So, I don't have many different angles to view things from.
That said though, the provider we are using for IPv6 seems to be doing it right, it just doesn't feel like IPv6 has the same "mesh" yet where who is connected to who doesn't really matter that much.
Thank you for sharing your experience!BTW, what timeframe are we talking about? Things have changed massivelyover the last 12-18 months.
We threw in the towel (pulled AAAA records) about 6 weeks ago, and started IPv6 experimentation about 16 weeks ago.
I'll be writing up a paper going into a lot more detail about what went right, what went wrong, and why the decision was made to revert back to IPv4 soon, if anyone is interested.
-- kevin
Current thread:
- Re: Addressing versus Routing (Was: Deploying IPv6 in a datacenter), (continued)
- Re: Addressing versus Routing (Was: Deploying IPv6 in a datacenter) sysadmin (Dec 21)
- Re: Addressing versus Routing (Was: Deploying IPv6 in a datacenter) Daniel Roesen (Dec 21)
- Re: Addressing versus Routing (Was: Deploying IPv6 in a datacenter) Stephen Sprunk (Dec 21)
- Re: Addressing versus Routing (Was: Deploying IPv6 in a datacenter) Kevin Day (Dec 21)
- Re: Addressing versus Routing (Was: Deploying IPv6 in a datacenter) Jeroen Massar (Dec 22)
- Re: Addressing versus Routing (Was: Deploying IPv6 in a datacenter) Kevin Day (Dec 22)
- Re: Addressing versus Routing (Was: Deploying IPv6 in a datacenter) Daniel Roesen (Dec 27)
- Re: Addressing versus Routing (Was: Deploying IPv6 in a datacenter) Michael . Dillon (Dec 22)
- Re: Deploying IPv6 in a datacenter (Was: Awful quiet?) Kevin Day (Dec 21)
- Re: Deploying IPv6 in a datacenter (Was: Awful quiet?) Daniel Roesen (Dec 21)