In order to view camera from different network connected computer and most importantly to be able to download recorded video files , we need two
things: Static IP from your internet provider ( cost around 50 euro - once off charge ) and Port Forwarding.

By default, your IP address changes every so often. So if to compare it to the phone number - you can call anyone, but they can not call you as your phone number ( IP address ) keeps changing.  To access your camera from different network, you will need IP address that does not change. 
Call your Internet Provider and ask for static IP address. Another option is to create DDNS account with www.noip.com , however that costs too ( $25) per year and not worth a hustle if you can get static IP.

Port forwarding - is allowing access to your camera on it's internal address ( 192.168.1.88 ) or whatever it is from computer on other network ( from outside ).
The easiest way is to call Internet Provider and ask them to forward ports 80 and 554 to your camera on 192.168.1.88.
However if it is not successful please refer to www.portforward.com or to the screenshots below.
Screenshots show how to forward ports on Eircom's D-1000 router. 

First, login to your router:
Go to Network Setting , click NAT
Click Port Forwarding
Click Add new rule and do as per screenshot. Change Service name if you wish.
Add second rule.
Click Apply and go to Security --> Firewall
Click Low radio button , click Apply. Log out. That's it. Took me 10 minutes.

I have recently had a hustle of forwarding a port on Eircom F1000 router. Took me some time and I captured screen-shots.

 Leave WAN IP Field empty. Server IP Address is your camera or NVR.




This is info for forwarding Vodafone router:




That's all for now :)