[ax25-layer2] layer 2 hub and switch

[Jason Winningham]

On Sep 21, 2005, at 5:52 AM, Andre PE1RDW wrote:

> In the layer 2 ethernet world we have seen hubs being replaced by  
> switches to improve throughput.
> Would in the layer 2 ax25 world a straight trough digi be the same  
> as a hub and flexnet type digi be a switch?

An ethernet hub is a repeater - if it receives a packet on one port,  
it transmits that packet on all other ports.

An ethernet switch (early coax/AUI models were known as bridges)  
keeps a table of heard MAC addresses for each port.  If it learns  
that MAC address ABC is on port 1, afterwards any packet addressed to  
ABC will only be transmitted on port 1.  If a switch/bridge receives  
a packet where it does not have the destination MAC address in any  
table, it will transmit that packet on all ports.

Ethernet terminology shifted with the use of twisted pair: if a  
repeater is used with coax or AUI connections, it's known as a  
repeater, but if it has UTP connections, it's called a hub.   
Likewise, a bridge has coax or AUI connections, but if it has UTP  
connections it's a switch instead of a bridge.

Sorry, I don't know how flexnet works to know if your analogy is  
correct, but maybe this will help.

-Jason
kg4wsv