IPv6 support on Virgin media

[dgcarter]

Does anyone know whether (and if so when) Virgin plan to implement IPv6 on its network?

[Dagger2]

[...] shows them having just shy of 9.5 million IP addresses. They have less than 6 million customers so I find it difficult to see where those other IPs have gone

This is a bit of a tangent to the rest of the thread, but... that's not how IPs work. They're not MAC addresses; IPs use hierarchical allocation that, unlike MAC addresses, isn't dense, and this is for really good reasons.

Imagine you had a cable segment with 750 customers on it. How many IPs do you allocate for the on-link addressing? Since there are 750 customers, do you (ignoring network and broadcast addresses, for simplicity) use a /23 plus a /25 plus a /26 plus a /27 plus a /29 plus a /30 plus a /31, giving you exactly 750 addresses? If so, then what do you do when the cable segment expands or shrinks by one customer?

That would be pretty crazy. How about just a /23 and a /24, giving 768 addresses? This is less crazy, but it's still two separate blocks, and what happens when 20 more customers sign up and now you're out of room and have to find more space and renumber?

In reality you'd most likely put a /22 on that network segment, allocating 1024 addresses for the WAN addressing of 750 customers. You end up "wasting" a quarter of your addresses, except it's not wasting because we are getting a use out of them -- they're being used to reduce the level of crazyness in the network.

6 million addresses used out of 9.6 million total is actually really high (it's a HD ratio of something like 0.97!), and indicates that VM are spending a lot of energy on address conservation. No prizes for guessing who ultimately pays for that.

[VMCopperUser]

I would have thought DHCP servers were in each of their 13 main locations and each one of those would dish out to the whole area.

They have the ability to assign a static IP to every customer too so wouldn't that make your view of how they assign addresses a non-issue?

And... Back to another question as such...

In the way you show the system, they are fighting to keep IP's open for customers.  But once they introduce a tunnel layer then it should be easy for them to have less worry about address conservation right?..

I am not against the tunnel aspect of cgnat, just that it's going to make some things not work at all.

I expect (partially by design, shame on me for thinking it) cgnat to break ipv4 SIP and p2p.  I do look forward to some of the testers feeding this info back and hopefully everything being okay in the end. 

[chrcoluk]

Static ip's doesnt prevent you from needing to assign network blocks, so would still be wastage.

Dagger's post is excellent.

[Morgaine]

Sunday update --- still no significant changes since IPv6 activity hit bottom on 2018-04-10:

Meanwhile, BT's IPv6 growth continues effectively flat-lined as I described a fortnight ago, so this would be a good time for Virgin to begin customer IPv6 trials and potentially leap ahead not long after.

Morgaine.

[Dagger2]

The DHCP servers might be centralized, but where you put your DHCP servers is separate from your network layout. You don't really want half a million customers on a single L2 broadcast domain.

They have the ability to assign a static IP to every customer too so wouldn't that make your view of how they assign addresses a non-issue?

Maybe to any customer, but not necessarily to every customer simultaneously. I don't know how VM does static IPs, but a method which works for a few thousand customers (say, injecting /32 routes per customer) will not necessarily scale to a few million customers.

But once they introduce a tunnel layer then it should be easy for them to have less worry about address conservation right?

It would probably help somewhat, because you can move tunnel clients between tunnel servers a lot more easily than between DSLAMs. So long as you don't care about their IPs changing, you can just shuffle them around to wherever there's space.

Just... don't bother getting your hopes up. DS-lite is specced as doing CGNAT, and I find it really very unlikely that they'd bother setting up any mechanism to avoid it. At best you might be able to convince them to put you back onto the v4-only platform.

[VMCopperUser]

I still have the SH 2ac modem/router so not much worry for now about moving to the DS-Lite mixture as I cant see them firmware upgrading old hardware (Been around long enough to know they abandon older gear/plans).

As my phone (SIP) nor any of my voip providers (SIP) handle IPv6 then virgin media are - in essence - killing my VoIP service.  I know there are work-arounds.

Plus this rollout will probably be staged.  So I find it quite laughable that once it starts happening, some parts of the VM network will not be reachable (hosted servers) by other parts of the VM network.

[TonyJr]

As a side note, at the current rate, it will probably be faster to use this instead of waiting for VM’s rollout : 

https://tools.ietf.org/html/rfc6214

which is an appropriately updated version of this

https://tools.ietf.org/html/rfc1149

I hope this brightens your day, even if if it is just a little.

[ravenstar68]

@TonyJr

RFC1149 was actually implemented though 😉

http://news.bbc.co.uk/1/hi/sci/tech/1321176.stm

teehee

Tim

[Morgaine]

Sunday update --- again, no really significant changes since IPv6 activity hit bottom on 2018-04-10:

 

I expect I'm not the only one looking for signs of the purported customer trial, but the current growth is so excruciatingly small that attributing a meaning to it probably wouldn't be on very solid ground.  Here are July's APNIC figures so far:

DATE         AS      Users        IPv6-Users  %UKv6
==========   ==      ==========   ==========  =====
2018_07_01:  VIRGIN  13,173,862        1,044   0.01
2018_07_02:  VIRGIN  13,167,101        1,047   0.01
2018_07_03:  VIRGIN  13,162,874        1,055   0.01
2018_07_04:  VIRGIN  13,164,219        1,072   0.01
2018_07_05:  VIRGIN  13,160,905        1,087   0.01
2018_07_06:  VIRGIN  13,177,468        1,094   0.01
2018_07_07:  VIRGIN  13,194,031        1,102   0.01
2018_07_08:  VIRGIN  13,191,860        1,103   0.01

If those tiny numbers are signs of a customer trial then it's clearly not very popular, although maybe that could be explained by Virgin's counterproductive penchant for secrecy and the widely disliked straightjacket of NDAs.  An open trial would not only attract more participants but also generate valuable community buzz about Virgin finally showing off its IPv6 in public.

Morgaine.

[VMCopperUser]

Opening it up to the tech'type people who often do the trials (I have not been offered a trial for a long time) just means that users who are more likely to use IPv4 forwarding and services that are mainly IPv4 could end up staying clear of the trial just because they want things to keep working.

Port forwarding (IPv4) is nearly impossible for some people to understand.  UPnP has helped most people avoid the problems with NAT and how to set forwarding.

When this CG-Nat change fully rolls out anything that's IPv4 required that uses port forwarding (User Set or UPnP) will stop working... Virgin media's savings in ipv4 management (as suggested earlier as a possible reasoning of DS-Lite) will be fully offset by them having to deal with more service calls and some users leaving the service.

No doubt the trialist will be forcing IPv4 on a lot of things for the same reasons and that could be why stats are low.

I personally would like to start switching to IPv6, there are other benefits than what we just see now.  But I am sure that Multicast will be blocked, and god knows if the routing will see the gains that it should.  Also as larger ISPs sign up to IPv6 we should start seeing more content providers being forced to move this way, and hardware providers too.  I don't have a IPv6 firewall but that is something I would need to invest in.

Plus I have tons of questions, like above, how will VM's implement a IPv6 firewall.. I mean at the basic level it should be Stateful IPv6 similar to the blurry layer that NAT provides, but is it going to support UPnP or will your device just be open the the wild world (I can't see them doing that).  But if we need to change our gateway devices to Modem + Firewall (IPv6)+WAP, vs Modem+Router then will this be supported?