Module 2 Spanning Tree Protocol Flashcards
Who invented the STA Algorithm?
Radia Pearlmen
_____ is the solution for achieving necessary network availability
Redundancy
This issue is known as the ethernet ports does not have the capability to drop frames that propagate endlessly
MAC Database Instability
This can cause Denial of Service when too many network devices consume a lot of traffic for the legitimate traffic to go through
Broadcast storms
This issue refers to having multiple duplicate frames going to a network device
Duplicate Unicast Frames
How does STP Algorithm work?
Select a root bridge to form a single least cost path
This prevents loop in the work or in the topology
Spanning-tree
What does STP sends to L2 devices to calculate the one logical path?
BPDU Frames
What is the meaning of BPDU?
Bridge Protocol Data Unit
What happens to the redundant paths in the STP?
It is dynamically blocked and will be unblocked if the main path is closed
What are the steps of STP??
- Elect Root Bridge
- Calculate Path cost
- Select Root switch
- Select Root ports
- Select Designated ports
- Select Non-designated ports
Each BPDU contains a ____ which is used to identify which switch it’s sent from.
BID
What happens in the first step of the STA?
It selects a single root switch as a reference for all calculations which is accompanied by its BID.
A switch will send out a BPDU frame every 2 seconds to all switches and when the received BID is lower, the switch BID will update.
What happens during the second step
It sums all the individual possible path that it took. The lowest one will be the “best path”
Default port costs are specified by _____ and what are those corresponding values?
IEEE
10 GBPS - 2
1 GBPS - 4
100 MBPS - 19
10 MBPS - 100
How are port roles assigned?
It depends on the position of the switch
What are the different type of roles of ports?
Root
Designated
Non-designated
What is a root port?
The switch with the lowest cost path will forward traffic to this bridge
What is a designated port?
This is the port that receives and forwards traffic to the root bridge as needed. Only 1 is allowed per segment.
What is a non-designated port?
A switchport that is blocked.
What are the operations of each port?
Blocking
Listening
Learning
Forwarding
Disabled
What is PVST+?
One spanning-tree for each vlan instance
No load sharing
One uplink must block for all VLANs
What is Cisco PVST+
Each vlan has its own independent spanning-tree instance
One port can be blocking for one VLAN and forwarding for another VLAN
Can load balance
What are the 2 different ways of adjusting bridge priority?
priority <multiples of 4096>
root <primary | secondary>
BPDU timers can affect _____
DHCP
This setting or command puts the port into a forwarding state
Portfast
