Flashcards in Week 1 Deck (20):
What is the Rapid Spanning Tree Protocol (RSTP)?
IEEE 802.1w standard
Replacing and backwards compatible with IEEE 802.1d (STP)
RSTP prevents layer 2 loops
By determining best traffic path through the network
Links are blocked when they aren't apart of the best path
What is a Bridge ID?
It is a unique ID for each bridge
Combination- Priority # (1-64k) and base Mac address
ex 1: priority: 32768
ex 2:priority: 32768
what is a Root Bridge?
The focal point for all paths
- the root bridge is the switch with the lowest bridge ID
Bridge Protocol Data Unit (BPDU)
- STP config frames
- sent between neighbour switches over native VLAN
What is Port cost?
- cost of using the port
this is based on bandwidth + ID
what is path cost?
Total cost of path from switch to root bridge
List the STP post cost for each of the following speeds:
Speed - cost
10 mbps - 100
100 mbps - 19
1 gbps - 4
10 gbps - 2
How is a Root Bridge chosen?
It should either be a distribution or CORE switch
Typically configured in STP, root bridge is elected in STP, and lowest bridge ID wins.
we can lower the priority to change the bridge ID to a designated port
How can you configure a Root bridge?
- you reduce the priority on the desired switch
Spanning-tree VLAN (n) priority (x)
n= native VLAN number
x= selected priority (default is 16384)
What is a Root Port?
Port on a switch with the lowest cost path to Root Bridge
one per switch
frames forward through root ports
What is a designated port?
All root bridges are designated
- a port on a switch with lowest cost path from the root bridge
- forwards traffic
What is the role of the backup port
Path to route via another port, same segment
What is the role of the alternate port?
Pth to route via another port. Different segment
What are the four port states?
- Forwarding- forwards traffic
-Discarding - no traffic sent, listens
- Learning- no forwarding, learn MAC addr + builds table, part of convergence process
- Converged- all ports in final state
The port on a non-Root bridge that is closer to the root bridge in terms of cost
The port on a network segment that is closest to the root bridge in terms of cost
Non designated port
Port that blocks traffic in order to preserve a loop free topology
port that is administratively shut down
All switches exchange info to use for the subsequent configuration of the network
Each switch compares the parameters in the BPDU that it sends to neighbpur with the parameteres int the bpdu that it recieves from other neighbors
Inside the bpdu is the bridge id