Comcast Activates First Users With IPv6 Native Dual Stack Over DOCSIS

http://blog.comcast.com/2011/01/comcast-activates-first-users-with-ipv6-native-dual-stack-over-docsis.html

by there • 15 years ago

37 23 15 years ago

blog.comcast.com

zitterbewegung• 15 years ago

This is great :-) I hope more Internet Service Providers follow suit! I'm actually glad for once that I have comcast.

ronnier• 15 years ago

Comcast also caps usage to 250GB per month.

http://customer.comcast.com/Pages/FAQViewer.aspx?Guid=3ca542...

gergles• 15 years ago

FWIW, it's a softcap. I have several friends who have gone well over (we're talking 1TB+) and haven't received the dreaded phone call.

pquerna• 15 years ago

FWIW, we hit 256gb, and we got a call, threatening if we passed it again in 6 months we would be banned from Comcast for 12 months. (Someone in the house accidentally left a torrent sending for 3 weeks)

Locke1689• 15 years ago

How is this relevant?

hcurtiss• 15 years ago

18 quintillion . . . why?

shkb• 15 years ago

Well we ran out of 4 billion, and much of the world isn't really online yet. Then factor in having a laptop, a smartphone, gaming console, HPTC, etc. There's more servers and infrastructure too. It's not that much overkill either, only 4x more bits.

jmillikin• 15 years ago

The article states that 18 quintillion is being allocated to each customer, which does seem a bit excessive.

SoftwareMaven• 15 years ago

Not sure why the down-votes. I was surprised that they were allocating 64 bits of address space to each user as well, but I don't know the details of IPv6. I think I'd be OK with 16 bits myself. :)

InclinedPlane• 15 years ago

Effectively unlimited is better than limited. It turns out that the difficulty of supporting an 18 quintillion large address space is not significantly different from the difficulty of supporting a 4 billion large address space. NTFS5, for example, can support file sizes up to 18 quintillion bytes, and it's a decade old.

pyre2• 15 years ago

  > NTFS5, for example, can support file sizes up to 18 quintillion
  > bytes, and it's a decade old.

IIRC, NTFS has loads of advanced features, but Microsoft is slowing "turning them on" by adding support for them in Windows. I'm sure Windows would blow up if you got anywhere near that limit.

drdaeman• 15 years ago

Because that's the minimum block size (/64) for several IPv6 features - mostly important the stateless address configuration - to work.

I'd thought of explaining with my own words, but found very good and detailed explanation here: http://serverfault.com/questions/182881/why-add-an-ipv6-addr..., so I'd just quote.

--- begin quote --

The IPv6 addressing architecture (RFC4291) requires all unicast addresses always have a prefix length of 64 bits. Using something other than a /64 will break a number of IPv6 features such as neighbor discovery, secure neighbor discovery (SEND), privacy extensions, mobile IPv6, embedded-RP (multicast), etc.

The current IPv6 address assignment guidelines call for allocating a /64 only when it is known that one and only one subnet is needed, otherwise a /56 should be allocated to small sites that are "expected to need only a few subnets over the next 5 years", or a /48 for larger sites. (ARIN policy 6.5.4.1)

--- end quote ---

This is why all those just-bit-counting "number of atoms in universe" and "79 octillion times" comparisons are wrong. Actual comparison should compare single IPv4 address with something ranging from /64 to /48 IPv6 allocation - /64 is a minimum per L2 broadcast segment - so it's a minimum per-customer allocation (unless ISP is really greedy). Also, I don't know of reasons, but RIPE NCC themselves uses /32 IPv6 block with about /21 IPv4 one comparison to calculate LIR billing score - http://ripe.net/membership/billing/calculation.html

j_baker• 15 years ago

Fun fact: the square root of the number of available IPv6 addresses is 18 quintillion. Therefore, there are 18 quintillion blocks of 18 quintillion addresses. We're not going to run out anytime soon.

dfox2• 15 years ago

Actually, /64 seems too small for customer allocation. What if customer wants to have more than one network?

ballen• 15 years ago

Odd I've had IPv6 on Comcast in the Northern NM area for at least the last three months.

Splines• 15 years ago

You were probably on the 6RD IPv6 trials: http://www.comcast6.net/faq.php

jtchang• 15 years ago

Is anyone else surprised that Comcast has actually gotten off their ass and decided to start going ahead with this? I guess my expectation was that Verizon would be headlining IPv6 and not Comcast.

allenbrunson• 15 years ago

Okay, if we're really starting to do this, then I guess I have to figure out how to upgrade all my code to deal with IPV6. I use the BSD sockets interface for most things.

I assume we'll be living in a mixed IPV4/IPV6 world for awhile. Who's got a tutorial for making a connection to a host using IPV6 if available, but falling back to IPV4 if it isn't?

dfox2• 15 years ago

See getaddrinfo(3) man page, that should be almost all you want. Making code mixed v4/v6 that way actually seems easier than v4-only solution with gethostbyname(3) and building struct sockaddr manually.

Comcast Activates First Users With IPv6 Native Dual Stack Over DOCSIS

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