Dual stack IPv6 for IPv4 depletion

Mel Beckman mel at beckman.org
Mon Jul 6 13:44:18 UTC 2015


And let's all complain to the MPLS working group to get IPv6 support finished up!

 -mel beckman

> On Jul 6, 2015, at 6:27 AM, Lee Howard <Lee at asgard.org> wrote:
> 
> Some thoughts. . .
> 
> ³Native dual-stack² is ³native IPv4 and native IPv6.²
> 
> ³Dual-stack² might be native, or might by ³native IPv6 plus IPv4 address
> sharing.²
> 
> Your IPv4 address sharing options are CGN, DS-Lite, and MAP. There are
> operational deployments of all three, in the order given. You need them
> close enough to your customers that traffic will return over the same
> path. You can¹t share state among a cluster of boxes, but that¹s not the
> end of the world; a device failure sometimes causes loss of state. MAP is
> the hot new thing all the cool kids are doing.
> 
> Look to your router and load balancer vendors for devices that do these.
> CGN is the only one that doesn¹t require updates to the home gateway. The
> more IPv6 your customers use, the smaller your CGN/AFTR/MAP can be.
> 
> Think about how you¹ll position it to customers. It¹s difficult to change
> a customer¹s service mid-contract. At some point, a customer is no longer
> profitable: if NAT costs and service calls add up, you may be better off
> buying addresses or losing the customer. You may need to buy some IPv4
> addresses to give you time; contact a broker.
> 
> You may be surprised how hard it is to root IPv4 out of the system. Don¹t
> buy anything you can¹t manage over IPv6, including servers and
> applications. Sorry, vendor, I can¹t buy your cluster, I don¹t have the
> IPv4 address space to provision it.
> 
> Lee
> 
> On 7/4/15, 8:09 AM, "NANOG on behalf of Josh Moore"
> <nanog-bounces at nanog.org on behalf of jmoore at atcnetworks.net> wrote:
> 
>> Traditional dual stack deployments implement both IPv4 and IPv6 to the
>> CPE.
>> Consider the following:
>> 
>> An ISP is at 90% IPv4 utilization and would like to deploy dual stack
>> with the purpose of allowing their subscriber base to continue to grow
>> regardless of the depletion of the IPv4 space. Current dual stack best
>> practices seem to recommend deploying BOTH IPv4 and IPv6 to every CPE. If
>> this is the case, and BOTH are still required, then how does IPv6 help
>> with the v4 address depletion crisis? Many sites and services would still
>> need legacy IPv4 compatibility. Sure, CGN technology may be a solution
>> but what about applications that need direct IPv4 connectivity without
>> NAT? It seems that there should be a mechanism to enable on-demand and
>> efficient IPv4 address consumption ONLY when needed. My question is this:
>> What, if any, solutions like this exist? If no solution exists then what
>> is the next best thing? What would the overall IPv6 migration strategy
>> and goal be?
>> 
>> Sorry for the length of this email but these are legitimate concerns and
>> while I understand the need for IPv6 and the importance of getting there;
>> I don't understand exactly HOW that can be done considering the immediate
>> issue: IPv4 depletion.
>> 
>> 
>> Thanks
>> 
>> Joshua Moore
>> Network Engineer
>> ATC Broadband
>> 912.632.3161
> 
> 



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