nanog mailing list archives

Re: Dual stack IPv6 for IPv4 depletion


From: andrew <andrew () ethernaut io>
Date: Mon, 06 Jul 2015 11:02:37 -0400

Ah, thanks.  I was considering this from a CE only perspective.


-andrew-------- Original message --------
From: Mel Beckman <mel () beckman org> 
Date: 07/06/2015  10:49 AM  (GMT-05:00) 
To: andrew <andrew () ethernaut io> 
Cc: Lee Howard <Lee () asgard org>, Josh Moore <jmoore () atcnetworks net>, nanog () nanog org 
Subject: Re: Dual stack IPv6 for IPv4 depletion 


MPLS requires an IPv4 core. You can't run an IPv6-only infrastructure  because neither CSCO or JNPR have implemented 
LDP to distribute labels for IPV6 prefixes. 




-mel via cell


On Jul 6, 2015, at 7:15 AM, andrew <andrew () ethernaut io> wrote:






Pardon my ignorance - what do you see missing in MPLS in regards to support for IP6?
-------- Original message --------

From: Mel Beckman <mel () beckman org> 

Date: 07/06/2015 9:44 AM (GMT-05:00) 

To: Lee Howard <Lee () asgard org> 

Cc: Josh Moore <jmoore () atcnetworks net>,
nanog () nanog org 

Subject: Re: Dual stack IPv6 for IPv4 depletion 




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 () 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 () nanog org on behalf of
jmoore () 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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