CGNAT Solutions

Wed Apr 29 14:25:41 UTC 2020

hey,

> I'm wondering if there are any real world examples of this, namely in
> the realm of subscriber to IP and range of ports required, etc.  ie: Is
> is a range of 1000 ports enough for one residential subscriber? How
> about SMB where no global IP is required.
> 
> One would think a 1000 ports would be enough, but if you have a dozen
> devices at home all browsing and doing various things, and with IOT,
> etc, maybe not?

1000 ports doesn't mean you can have at max 1000 layer-4 sessions at 
once. It means you can have 1000 sessions to single destination IP+port. 
You can reuse same source port numbers for different destination IP or 
even destination port.

We are seeing very good results with 256 ports per subscriber in the 
mobile scenario where consumer is mobile handset. So not directly 
translatable to broadband setup but still good datapoint.

If you must go CGNAT today it's only reasonable to use PBA (so you log 
only block allocations) or pure deterministic where you have strict 
mapping between inside IP and outside IP+portrange so you don't need any 
logs at all.

-- 
tarko