Mostly they depend on your network device(s) being able to keep track of the information and the tools just query the devices and present for you in a useful way.
Common in Cisco networks is the use of NetFlow (technology) for this purpose. Once can use a tool like ntop (open source), Solarwinds Netflow Traffic Analyzer (free for real time few device view, licensed for archiving and more devices), ManageEngine's Netflow Analyzer (free 30-day demo, licensed for long term use), etc. You typically need a router or high end core switch that supports NetFlow - small layer 3 switches and layer 2 devices will not.
Some other devices (e.g., load balancers like F5 LTM and Citrix Netscaler) also instrument things like http req/sec etc. and can be queried using SNMP management tools (such as Cacti - open source or Solarwinds Orion NPM - licensed) to display utilization.
NetFlow is the best technology to get information on traffic based on application, port, protocol, IP Address, etc. There are a lot of free tools you can make use of or go for a licensed tool as per your requirements.
You may find the below link useful to select a free tool.
From the list, ManageEngine, Solarwinds and Plixer are market leaders with both free and licensed versions available. ManageEngine and Plixer, both support stand alone NetFlow installations whereas Solarwinds requires a base software for installing NetFlow monitoring module. Full fledged Linux version is available with ManageEngine.
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
practices to identify possible threats and take security measures. It
provides an overview of basic multicast, the best security practices for
use of this technology, and recommendati...