The prediction that one day we will run out of IPv4 addresses is often seen
as a warning with little substance to it, and many providers appear to see
little point in implementing IPv6 at this time. The predictions though may
becoming true, as Plusnet moves to start a Carrier Grade NAT trial, to help conserve
the number of IPv4 addresses they need.
“We need a bit of help with some testing over the next few weeks. As many
people will probably know there’s a finite number of IP addresses in the world
and there aren’t many left. In order to ensure that people have access to the
Internet during the transition to the new world of IPv6 ISPs like ourselves are
looking at options including Carrier Grade NAT. Even if the world switched on
IPv6 today there would still be people and applications that don’t work under
IPv6, some games consoles for example. As such everyone will still need an IPv4
address for the foreseeable future.”Plusnet seeking customers to trial carrier grade NAT
Carrier Grade NAT has been used by mobile operators in the past, and the
result for ADSL and fibre connections is that the router in the home would be
handed a private network IP address. This creates several problems (1) services
that rely on port forwarding/UPnP will not work (2) if the private IP range is
the same as routers LAN side this can cause routing issues (3) services like
VPN that use a public IP for security checks may fail.
“All ISPs should be providing proper IPv6 first, and using NAT purely as a
stop-gap. This will allow innovation to continue and use the end to end design
of IP, and it will mean services using IPv6 will ‘just work’.At AAISP we have been providing IPv6 for over 10 years now, and we expect to be
able to provide at the very least a single fixed IPv4 address per line without
carrier grade NAT for many years to come.”Comment from Adrian Kennard of AAISP UK
Hopefully Plusnet will implement IPv6 swiftly, the BT Wholesale platform
supports dual stack IPv4 and IPv6 connections already. None of the major
broadband providers in the UK support IPv6 yet, and while there is no
compelling IPv6 application as yet, by starting to switch now the providers can
avoid a big confusing rush in a couple of years.
One of the common problems for the consumer is that some hardware,
particularly current generation games consoles do not support IPv6, if the next
generation consoles do then the problems of configuring NAT may at last be
consigned to history, but only if broadband providers support IPv6.
A slight chicken and egg situation does exist and that is support for IPv6
in consumer routers, but the situation is improving and the buying power of the
larger providers will quickly change that.
Update 4pm: Adrian Kennard has written a longer
blog article going into greater depth about the problems carrier grade NAT
can introduce.
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Hopefullt Plusnet will implement their CGN using the shared address space detailed in http://tools.ietf.org/html/rfc6598 rather than private IP space. This will mitigate problem (2) above.
Offering a static translation (where you’re always NATed out on the same public address which may be shared with others) may help (3) also.
If it breaks p2p uploads a bit, it might help with the bandwidth hogs on their new unlimited tarriffs too…
This is ‘get what you pay for’ Internet access. Pay little, get little. I’m sure it’s fine for people who want nothing more than an ‘essentials’ connection for web browsing and e-mail. A bold welcome to the ‘tiered’ internet. Static translation will be ‘fun’ when the few IPv4 addresses NATed out get blocked for spam / abuse, however spurious the reason. Serious P2P users would have to pay extra for a seedbox.
Sensible measure I think….
The majority of customers who just want to surf the net won’t be affected by a CGN.
Gives a good price break tiering I think to the more hardcore users.
Using a CGN will also increase security and put the task with PlusNET, as no inbound attacks will route back to a single ADSL client.
To Adrian K: there is a compelling IPv6 application, it’s called Google, who offer many of their services on IPv6 already. We just need them to announce they’re turning off IPv4 on some services to get people focussed.
It’s disappointing that an ISP is trialling CGN before finishing IPv6 deployment to their customers.
@speculatrix You cant expect google to do that. You cant expect any supplier to do that.
How about charging for ipv4 addresses, which gradually goes up every year. ISP’s a with a lot of users would save money by switching users to ipv6 (and tunnel ipv4 NAT). End users can always pay extra to have ipv4.
How do ISPs monitor/track usage and or illegal practices if many share one public address?
Sorry, another thought.
Does the contention ratios change or remain the same if CGN is in force?
so they as expected left ipv6 too late, germany is already rolling out dual stack to customers, and we have carrier grade nat? fail!!!
tThe one problem is how many routers/modems can cope with IPv6? I know none of my ADSl routers. Not sure about the cable modem, i saw something about IPv6, but not really took any notice.
I have a Chrome plugin, that shows me when a site I am looking at is ipv6. Loads of sites are these days, including this one.
Beggars belief Plusnet are talking CGN, and haven’t even got ipv6 running!
The danger is that ISPs use CGN to extend the life of IPv4. They then consider issuing dedicated IPv4 addresses on a paid-for basis, a bit like static IP addresses with some companies now.
It’s not a solution I’d welcome, but since ISPs are so slow with IPv6 roll out, you start to wonder if they just want to find an IPv4 solution such as this and forget about IPv6 altogether.
routers can support ipv6 with a firmware upgrade, its a fairly simple process to rollout firmware updates to isp supplied routers and to update ones not shipped out yet. Routers is a non issue since router vendors follow what the market demands, if ipv6 is supplied by the isp then retail routers will support and also vendors will alter firmwares as isps dictate.
olivier exactly my point, they seem to just be fighting of ipv6, and also possibly using it as a money spinner. we dont really know how many ip’s the likes of plusnet have left.
I think the government needs to step in, regulate the likes of CGN can only be used if ipv6 is in active deployment, in other words enforce it. Run out of ips and no ipv6? then no new customers until you get act together.
No really, we do not need the govt. mandating anything in terms of the internet and how networks are deployed. What we need from the govt. is them mandating that all new contracts for IT services/systems must be fully IPv6 functional like they did in the USA.
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