0x000B - Linux Virtual Bridges / Switch

0x000B - Linux Virtual Bridges / Switch

This becomes a very quickly confusing topic, and the way that Linux intermingles a 'bridge' with a 'link' and a 'device' can further confuse it.  Let's try to make this simple..

To understand the history we have to go back almost 30 years, and explain this as simply as possible.

Hubs - Simply they were ancient dumb analog devices that just re-broadcasted without caring to all the ports whatever 1 or 0 showed up. As more people joined the network segment -  This lead to network broadcast storms.  To solve this bridges were soon invented.

Bridges - Before ethernet switches even came to be - network bridges would alleviate network broadcast storms by being able to intelligently decide to drop or forard the ethernet frame.  Hence the term 'bridge'

After that intelligent Ethernet switches were soon introduced with store-and-forward mac table inspection that made hubs and bridges obsolete.

However Linux never stopped using these confusing terms.  But we will make this a simple as possible so that it's understandable..

# Install the following utils:
sudo apt install bridge-utils net-tools

Make a virtual bridge

# bridge control
brctl addbr myvirtualbridge

Inspect the Bridge(s)

brctl show 
brctl addbr myvirtualbridge

- another command:

brctl show virbr0
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