nanog mailing list archives
Re: IPv6 Deployment for the LAN ... anycast
From: Perry Lorier <perry () coders net>
Date: Sat, 24 Oct 2009 01:25:33 +1300
TJ wrote:
WRT "Anycast DNS"; Perhaps a special-case of ULA, FD00::53?You want to allow for more than one for obvious fault isolation and load balancing reasons. The draft suggested using <prefix>:FFFF::1FWIW - I think simple anycast fits that bill.
I think for very small/small networks anycast requires a lot of overhead and understanding. If your big enough to do anycast and/or loadbalancing it's not hard for you to put all three addresses onto one device.
There are some protocols that anycasting doesn't work well for, they may require multiple instances.
I personally would suggest getting a well known ULA-C allocation assigned to IANA, then use <prefix>::<protocol assignment>:1 <prefix>::<protocol assignment>:2 and <prefix>::<protocol assignment>:3, where <protocol assignment> could be "0035" for DNS, and "007b" for NTP, and if you're feeling adventurous you could use "0019" for outgoing SMTP relay.IMHO non-hex-converted port numbers works cleanly ... ?
Up to 9999, if you want to announce a service port 30,000 you're in trouble. Also quite a few protocols don't have "well known" ports, so may want to get things assigned. If you're doing assignment you could do nice things like 0x53 for DNS and then ports >9999 and protocols that don't have "well known" ports could get an unused one assigned to them.
In my humble opinion I'd have them registered, linking them to port numbers means that it's easier on the poor admins brain at 3am while diagnosing faults, but may cause various hassles in the future (see above).... Heck, start a registry (@IANA) and add in FD00::101, etc. ... Maybe reserve FD00::/96 for this type of "ULA port-based anycast allocation". (16bits would only reach 9999 w/o hex-conversion (if hex-converted could reserve FD00::/112 ... But would be less obvious))Thinking further, if simply based on port#s wouldn't even need a registry. Unless it was decided to implement the multiple-addresses-per-function mentioned above, then perhaps useful.
Current thread:
- Re: IPv6 Deployment for the LAN, (continued)
- Re: IPv6 Deployment for the LAN bmanning (Oct 21)
- Re: IPv6 Deployment for the LAN Iljitsch van Beijnum (Oct 22)
- Re: IPv6 Deployment for the LAN bmanning (Oct 22)
- Re: IPv6 Deployment for the LAN Perry Lorier (Oct 22)
- Re: IPv6 Deployment for the LAN bmanning (Oct 22)
- Re: IPv6 Deployment for the LAN Perry Lorier (Oct 22)
- Re: IPv6 Deployment for the LAN trejrco (Oct 22)
- Re: IPv6 Deployment for the LAN Perry Lorier (Oct 22)
- Re: IPv6 Deployment for the LAN Owen DeLong (Oct 22)
- RE: IPv6 Deployment for the LAN ... anycast TJ (Oct 22)
- Re: IPv6 Deployment for the LAN ... anycast Perry Lorier (Oct 23)
- Re: IPv6 Deployment for the LAN ... anycast TJ (Oct 23)
- Re: IPv6 Deployment for the LAN ... anycast Owen DeLong (Oct 23)
- Re: IPv6 Deployment for the LAN ... anycast Chris Adams (Oct 23)
- Re: IPv6 Deployment for the LAN ... anycast Perry Lorier (Oct 23)
- Re: IPv6 Deployment for the LAN Perry Lorier (Oct 23)
- Re: IPv6 Deployment for the LAN TJ (Oct 23)
- Re: IPv6 Deployment for the LAN Owen DeLong (Oct 23)
- Re: IPv6 Deployment for the LAN TJ (Oct 23)
- Re: IPv6 Deployment for the LAN Kevin Loch (Oct 21)
- Re: IPv6 Deployment for the LAN Andy Davidson (Oct 28)