IPv6 support on Virgin media
Does anyone know whether (and if so when) Virgin plan to implement IPv6 on its network?
Forum Discussion
Except the dual stack lite RFC 6333 specifies that NAT be carried out on the AFTR elements.
Here's the introduction to the RFC
1. Introduction
The common thinking for more than 10 years has been that the
transition to IPv6 will be based solely on the dual-stack model and
that most things would be converted this way before we ran out of
IPv4. However, this has not happened. The IANA free pool of IPv4
addresses has now been depleted, well before sufficient IPv6
deployment had taken place. As a result, many IPv4 services have to
continue to be provided even under severely limited address space.
This document specifies the Dual-Stack Lite technology, which is
aimed at better aligning the costs and benefits in service provider
networks. Dual-Stack Lite will enable both continued support for
IPv4 services and incentives for the deployment of IPv6. It also
de-couples IPv6 deployment in the service provider network from the
rest of the Internet, making incremental deployment easier.
Dual-Stack Lite enables a broadband service provider to share IPv4
addresses among customers by combining two well-known technologies:
IP in IP (IPv4-in-IPv6) and Network Address Translation (NAT).
This document makes a distinction between a dual-stack-capable and a
dual-stack-provisioned device. The former is a device that has code
that implements both IPv4 and IPv6, from the network layer to the
applications. The latter is a similar device that has been
provisioned with both an IPv4 and an IPv6 address on its
interface(s). This document will also further refine this notion by
distinguishing between interfaces provisioned directly by the service
provider from those provisioned by the customer.
Durand, et al. Standards Track [Page 3]
RFC 6333 Dual-Stack Lite August 2011
Pure IPv6-only devices (i.e., devices that do not include an IPv4
stack) are outside of the scope of this document.
This document will first present some deployment scenarios and then
define the behavior of the two elements of the Dual-Stack Lite
technology: the Basic Bridging BroadBand (B4) element and the Address
Family Transition Router (AFTR) element. It will then go into
networking and NAT-ing considerations.Note that the idea behind dual stack lite is the fact that IPv6 deployment is nowhere near as complete as it should have been, it was hoped (which is something I mentioned earlier, even though I had not read this document before today), that we would have dual stacked IPv6 and IPv4 BEFORE we ran out of usable IPv4 space.
Because that hasn't happened, we now have to look at how to retain IPv4 access for and users while still growing the internet as a whole.
In short DS-Lite now requires NAT on the AFTR element.
While it does discuss port forwarding at the AFTR it also suggests that ISP's may choose not to forward some of the well known service ports to end users (i.e. Ports 0-1023 e.g. port 80 TCP) Note that this won't affect outbound connections but will make it impossible to run web servers or personal mail servers.
So talking about Dual Stack-Lite with no NAT is to put it simply - a pipe dream.
Tim
I was reading through the RFC's the other day too.
I think that the RFC was written with the view that you would only use it when you needed it, and as such you should need CGNAT. It doesn't seem to explicitly state that you cant use the IPv4 end as a single point per user.
AS5089 has about 26 million IPv4's (If my math is correct) under the "Virgin Media" name. I am not going to go through all the SUB AS's to see what looks customer-ish, someone else here probably knows how to pull that info from the database with ease and parse it (I would have to do it one by one by hand).
They say they have 5.9 million cable customers, and 3.1 million mobile customers (hard for me to believe that one). So that's 9.1 million IP's at a minimum. Mobile customers have probably been under CGNAT since the start so lets cut that 3.1 million down. Europol says some providers have thousands of people per IP, but lets say that virgin limits us to 250 people per IP... So that knocks mobile down to 12,000 users.. Ignorable levels. Their old TV boxes could have a public facing IP I think? The new V6 box is now behind your NAT router (Designed to save on the v4 assignment?). They don't give nearly enough stats to even take a rough guess on this. But lets just take their numbers and shoot for 8 million. So 8+6= 14 million IP addresses.
I have a hard time seeing how they are out of IPv4 addresses. It was only a couple of years ago that they suggested they were a really long way off from even needing to worry about IPv4, the V6 box should have reduced that worry by a huge amount, and now all of the sudden they want to add CGNAT.
I am watching the IPv6 transition with a little interest.
Yesterday, I got put on a new CMTS with a new with a change of public IPv4 address and hop 2 (10.* IPv4) address. CMTS MAC identifies as Cisco, which it was before too. No such IPv6 activity reported by my CM though. Although this sounds obvious that it might be some sort of congestion clean-up/re-seg of some-sort, I was having absolutely no bandwidth/latency issues on 350meg even at very busy times so I call this move peculiar on my part. Would this sort of activity be evident of a transition?
They have a lot of announcements that look like this:
62.30.0.0/15 Virgin Media Limited 62.30.0.0/16 Virgin Media Limited 62.31.0.0/16 Virgin Media Limited
which is 65k IPs, not 131k. If you remove all of the overlapping announcements then I make it about 8.3 million IPs. bgp.he.net says "IPs Originated (v4): 9,471,488" including all of the customer prefixes, so that looks about right.
Comparing that 8.3 million figure vs your 14 million estimate... yeah. You didn't even account for infrastructure address use or allocation inefficiencies and you still ended up with an estimate that was 1.7x higher than the address space they have available. And you wonder why they want CGNAT?
Dagger2 wrote:SpoilerThey have a lot of announcements that look like this:
62.30.0.0/15 Virgin Media Limited 62.30.0.0/16 Virgin Media Limited 62.31.0.0/16 Virgin Media Limited
which is 65k IPs, not 131k. If you remove all of the overlapping announcements then I make it about 8.3 million IPs. bgp.he.net says "IPs Originated (v4): 9,471,488" including all of the customer prefixes, so that looks about right.
Comparing that 8.3 million figure vs your 14 million estimate... yeah. You didn't even account for infrastructure address use or allocation inefficiencies and you still ended up with an estimate that was 1.7x higher than the address space they have available. And you wonder why they want CGNAT?
Perhaps my understand of networks is just quite poor then, but why should any of the internal infrastructure (not connected to a external provider) use a public IP? I know a lot of the Microsoft switches for years now would show their private IP because the internal network didn't have Public IPv4's attached to them. VM should admin all of their equipment using a 10.0.0.0/8 assignments. Allocation inefficiencies will be high, BUT, 4over6 could be used to localize a lot of the exit points and help get rid of much of that wastage right? Sure they will need other servers (DNS/MAIL/Whatever Else) but in the scheme of things I would think that would be quite small, like in the 100's of IP's.
If your telling me that 26 million IP's can't allow a ISP to run more than than about 6 million customers then that makes me really scratch my head about how poorly these things are working.
- I'm telling you that they don't have anything close to 26 million IPs. You double/triple counted overlapping announcements.
Okay, I see what your saying now.
My guess on the 14 million was making the assumption that the STB received a public IP (does it, did it?). Even if it does, the old STB should work fine under CGNAT (from what I know of them).
And what about the mobile network, are those CGNAT or not (I know EE is, but my Three sims aren't), I don't have a virgin mobile so cant check.
They did say in the past they wouldn't look to deploy IPv6 until IPv4 ran out, to me the two were separate, but If your saying that they have ~9 million to spread around mobile (non cgnat) and home broadband then that would mean they have ran out of breathing room.
Although it's useful to know roughly how many IPv4 addresses Virgin has available, I doubt that it matters at all in terms of deployments, because the vast majority are sure to be sold off while the market price is high --- currently around $18 per single address, I read. The attraction is irresistible, and cashing in on it is made somewhat urgent by knowing that the price will plummet once IPv6 is the majority protocol and IPv4-based companies start bringing up IPv6 in panic.
Unlike many non-ISP companies out there, all ISPs know that IPv6 is creeping up on them even if they haven't yet deployed it to customers, and for an ISP it is not a viable option not to deploy if they want to stay relevant. Alas for an ISP, running dual stacks internally is about as welcome as a hole in the head, so they also know that their long-term direction is towards IPv6-only internally plus IPv4 gateways at the edge for backwards compatibility.
There will be exceptions to this appealing organization of course. Quite a few ISP businesses fill a specialist niche rather than the mass public one, and some will find a good role supporting the long tail and extra costs of IPv4. Not the mass public ISPs though --- it's far too painful and costly in terms of both manpower and equipment for them to do so. Even worse for the medium term, it limits the speed at which they can evolve.
And so, while I like having numbers and stats on everything, I think that the number of IPv4 addresses at Virgin's disposal will mainly determine the extra profit that will appear on their ledger from the sell-off of excess IPv4 address blocks. An estimate of the IPv4 addresses that they will need overall is probably well known to them (current session stats minus the number of IPv6-capable destinations), but how many they will need to satisfy those IPv4 users who can neither move to IPv6 services nor use tunneled IPv4 is an extremely hard estimation to make with any confidence.
One thing is certain though --- the number of people unavoidably tied to native IPv4 can only decrease with time, and that is probably a very welcome realization for Virgin. It means that they can err on the side of retaining fewer rather than too many IPv4 addresses, because time will heal any miscalculation.
Another interesting conclusion is that Virgin is probably quite eager to release IPv6 onto us so that they can know with accuracy how many IPv4 addresses they definitely cannot sell off at this point in time. Factor in a safety margin and the rest of their IPv4 blocks are pure profit. Clearly the earlier they know their numbers the better. :-)
Morgaine.
