Bridges

Question 1

What is the purpose of transparent bridges?

Answer 1

The purpose of transparent bridges is to keep the packet forwarding functionality transparent to the hosts

Question 2

Within a spanning tree of bridges, what are the configuration messages composed of?

Answer 2

1. ID of sending switch
2. ID of switch that the sending switch believes to be the root
3. The distance, measured in hops, between the sending switch and root

Question 3

Within a spanning tree of bridges, when would the data stored on a switch change?

Answer 3

When a better value (for root ID, distance) from a configuration message is found… so when:

1. ID of root is smaller than stored
2. same root ID but smaller distance
3. same distance but sending switch has smaller ID.

Question 4

What is the purpose of using spanning trees for bridges?

Would 2 adjacently connected switches always be able to communicate with each other when we are using spanning trees?

Answer 4

The purpose is to avoid sending data packets indefinitely, so switches, now knowing where host A is, don’t keep looping the data packet amongst themselves.

No, the way data-packets move in spanning trees is down to the root then up (if need be) to the respective switch.
Just because they are adjacently connected doesn’t mean that link was selected by the spanning tree algorithm.