Engineering Workshops

Provider-Independent Addressing

Engineering Workshops

PI Multihoming

• One possible answer to the multihoming/multiple address problem is the use of addresses determined by geography.

• Each site uses the location of its ISP demarc to determine its PI address space - put your GPS on top of your router.

Engineering Workshops

PI Address Calculation

• Lat/Lon each converted to a 22-bit binary number

40.0433N = 0001110001111001101010

105.2781W = 1011010100100010101101• Two values interleaved, latitude first0100 0111 1011 0001 0010 1110 1000 0110 1100 1101 1001

4 7 b 1 2 e 8 6 c d 9

X47b:12e8:6cd9::/48

• X because this scheme is not yet approved, but the expectation is that 1 will be used.

Engineering Workshops

PI Address Calculation

• Why interleave? So that as the prefix gets longer, the area included in the prefix gets smaller:

bits degrees nominal square scope sites

--------------------------------------------------------------------

4 -> 90.00000 10000 km octant

8 -> 22.50000 2500 km expanse

12 -> 5.625000 600 km zone

16 -> 1.406250 150 km region

20 -> 0.3515625 40 km metro 16777216

24 -> 0.087890625 10 km city 1048576

28 -> 0.02197265625 2.5 km locality 65536

32 -> 0.0054931640625 600 m neighborhood 4096

36 -> 0.001373291015625 150 m block 256

40 -> 0.00034332275390625 40 m lot 16

44 -> 0.0000858306884765625 10 m site 1

Engineering Workshops

PI Address Calculation

• If all the ISPs in an area meet at a local exchange, they may be able to aggregate PI addresses to some degree.

• But using PI will inevitably mean that more prefixes are carried in the default-free zone (DFZ) at the core of the Internet.

Engineering Workshops

PI Multihoming

ISP1UUnet

ISP2(WestCo)

IBM1528:8653:294C::/48

Ford1528:8653:29A6::/48

GE1528:8653:2905::/48

SOX1528:8653:28FE::/48

1528:8653:2800::/39

Engineering Workshops

PI Multihoming

• Proposed format: draft-hain-ipv6-pi-addr-02.txt

• Usage discussion: draft-hain-ipv6-pi-addr-use-02.txt

• Abilene PIA background and calculator: http://loadrunner.uits.iu.edu/~neteng/ipv6/pi/pi.html

• Remember, this is NOT a standard yet!