CGNAT

Mon Mar 1 19:38:15 UTC 2021

Kevin,

One of the presented options isn't like the others. As such the comparison isn't really fair, especially if you expect to run your business longer than 7 years.

If you buy more IPv4 space you will neither have to deal with CGNAT nor worry about traffic growth. Both of those benefits are easily worth the (short term) premium.

In the long term, buying more IPv4 blocks now is likely to be cheaper than running CGNAT for the foreseeable future.

To echo Owen, in general, the economics today still work out to make purchasing addresses more favorable than CGNAT.

- Jared

Sent: Tue Feb 2314:36:48 UTC 2021
From: Kevin Burke kburke at burlingtontelecom.com 
To: nanog at nanog.org
Subject: Re: CGNAT

We are looking at implementing a similar solution with A10 for CGNAT.

We've been in touch with A10. Just wondering if there are some alternative vendors that anyone would recommend. We'd probably be looking at a solution to support 5k to 15k customers and bandwidth up to around 30-40 gig as a starting point. A solution that is as transparent to user experience as possible is a priority.

The numbers below are for a similar target of subscriber’s and peak bandwidth.

We assumed a couple of numbers:
Current Peak Bandwidth = 40G
Remaining IPv4 traffic after migration = 20% (Seen references to 10% or 20% on this forum)
Future Bandwidth Growth = 2x (no data behind this assumption)
Future CGNAT’ed bandwidth = 15Gbps
Equipment & budget lifecycle = 7Yr

Getting that data led us to this price comparison:

Solution
Lifecycle/ Term
Annual Cost/Sub
Product Lifecycle Cost/Sub
Lease IPv4 Cogent
7
$     4.45
 $   31.13
A10 CGNAT 15Gb 7Yr
7
$     1.21
 $     8.47
A10 CGNAT 40Gb 7Yr
7
$     1.95
 $   13.68
Purchase @ $25 7Yr
7
$     3.57
 $   25.00

The current plan is implement an A10 CGNAT solution after upgrading our network for IPv6.  In the interim we will have to lease IPv4 to tide us over.

I would be curious to see what other’s estimate the costs of various approaches.  Feel free to ping me off-list for more specific numbers.

Kevin Burke
802-540-0979
Burlington Telecom
200 Church St, Burlington, VT