ICND2 Flashcards
What STP also known as?
Is sometimes called the Spanning-tree algorithm.
What does the spanning tree algorithm do?
it chooses the interfaces that should be placed into a forwarding state. For any interface not chosen to be forwarding will be in a blocking state.
STP uses 3 criteria to choose whether to put an interface in a forwarding state, what are they?
- STP elects a root switch and puts all working interfaces into a working state.
- Each non root switch considers one of its ports to have the least administrative cost between itself and the root switch.
- The switch with the lowest root cost as compared with the other switches attached the same link is placed in a forwarding state.
What are the 3 basic components of a LAN?
Ethernet NIC, Ethernet LAN switches and cables that connect devices.
When are broadcast storms introduced?
When a MAC address is not found in the MAC address table.
What does spanning tree do to prevent switch loops?
it places some switch ports into a forwarding state and others into a blocking state.
What does the spanning tree algorithm do?
the algorithm chooses which interfaces should be placed into a forwarding state.
what does a blocked link do?
it does not forward frames, but stays up and active to carry STP control messages.
What are BIDs and Hello’s used for?
to elect the root switch
how is the root port marked?
the port receiving the lower cost hello
What happens with switches advertising the same cost?
the switch with the lower BID wins and it’s port is the designated port
What does etherchannel do?
it combines multiple parrallel segments into a single link.
What does portfast do?
allows a port connected to a host to immediately into forwarding state.
what is BPDU guard?
it disables an access port if it receives BPDU’s
What is Rapid STP?
improves convergence by eliminating or reducing waiting periods.
