Question: I am currently working on connecting ip cameras together .
I am using cat7 sftp cable .

according to the bellow article :

<http://www.differencebetween.net/technology/difference-between-rj45-and-rj48/>

I understand that :

1. RJ45 is used with UTP cable only .
2. I can't use RJ48 because it will not fit into my NVR and SWITCHES .

I have two questions :

1. I found RJ45 which fit cat7 cable .

[https://www.amazon.com/dp/B071GXPTVZ/ref=twister\_B09ZYBKJFZ](https://rads.stackoverflow.com/amzn/click/com/B071GXPTVZ)

How could that happen ? RJ45 should be used with utp cables only ? right ?

2. what's the right connector to choose to connect cat7 sftp to ip camera ?

some people suggest to connect Cat6a Cat7 Keystone at the end of cat7 cable .

[https://www.amazon.com/dp/B074PKQ1S1/](https://rads.stackoverflow.com/amzn/click/com/B074PKQ1S1)

then to use short cat 6 cable to connect between the keystone and ip camera .

is that the correct method ?

Thank you

Answer: 
An IP address targets a host on the network layer. Transport layer ports multiplex an L4 protocol within a host (to different processes/services). Both are different things on different layers.

Basically, if you'd repurpose IPv6 addresses (or bits) for host-level multiplexing you'd gain very little but you'd break logic compatibility between IPv4 and IPv6. A transport layer protocol works the same way on any IP version.
> 
> Why do we need ports with IPv6?
> 
> 
> 

As Zac67 already said, it was intended to make IPv6 as compatible to IPv4 as possible to ensure that existing programs need not to be changed too much.

Keep in mind, that in IPv4, the destination port of a TCP connection also specifies the type of higher-layer protocol:

80 for HTTP, 443 for HTTPS, 23 for Telnet and so on.

So we need the TCP port in IPv6 as indication of the higher-layer protocol type if we want to be compatible to IPv4.

> 
> Why not assign each application, tab, etc... its own public IPv6 address
> 
> 
> 

I was already thinking about this: Doing this would allow implementing certain additional security and privacy features. So I can imagine that this will actually be done in the future.

And of course: We can get rid of URLs like `https://example:8443/`: Instead of using different ports (8443) on server side, we can simply use multiple IPv6 addresses.

However, it would still not allow us to get rid of the source port of a TCP connection:

I rembember some web-based application that requires two HTTP(S) connections to be established between the client and the server at the same time.

In this case, the server will surely check if both connections come from the same client (this means: same source IP address).

However, this means that both connections have the same two IP addresses and the same destination port (443 in the case of HTTPS). Therefore, they must have a different source port.

And if IPv6 should be compatible with IPv4, this web-based application must work the same way with IPv6 as it works with IPv4.