STP Fundamentals
Switches running STP will 1) build a map or topology of the entire switching network, 2) will identify if there are any loops, and then perform this action (3).
What is block or disable as many ports as necessary to eliminate all loops in the topology?
All ports on the root bridge are called designated ports and are set to this, which means they will pass data.
What is "forwarding"?
A broadcast storm can form in seconds and requires physical intervention to stop. Thus, STP will always take this approach.
What is proactive?
This allows a switch port to bypass the usual progression of STP states. The port will instead transition from a blocking to a forwarding state immediately, eliminating the typical 30-second delay. It's so powerful, it should only be used on ports connected to a host.
What is Port Fast?
True or False..VLAN should be created for small networks that have little traffic.
True or False...A blocked port cannot be reactivated if another port goes down.
What is false?
This type of port provides a constant connection to the root bridge for the non-root bridge to receive advertisements and updates.
What is Root Ports (Forwarding & Listening Mode)?
STP supported five port states, RSTP supports these three.
1. Discarding
2. Learning
3. Forwarding
This provides improved convergence if there is an indirect failure in the STP topology, and it allows a switch to bypass the max age timer.
What is Backbone Fast?
These are three benefits of VLAN.
What are:
1) Increased security
2) Flexibility and Scalability
3) No geographical barrier
This serves as the central reference point for the STP topology.
What is the root bridge?
In this port assignment, after a switch has determined the best path to the root bridge, all other ports are placed in the blocking state to prevent loops.
What is a non-designated (blocked) port?
Initially, a switch port starts in this state.
What is a discarding state?
This port is assigned to carry traffic for all the VLANS that are accessible by a specific switch. Its main purpose is to carry traffic between switches and to maintain the VLAN information.
What is the trunk port?
VLANs are identified using these.
What are numbers?
True or False...There can be only one Root Bridge per STP Instance.
True
These are the four STP port states.
What are:
Blocking
Listening
Learning
Forwarding
CISCO developed these three proprietary features that improve STP convergence time
What are:
1. PortFast
2. Uplink Fast
3. Backbone Fast
This improves convergence time for direct failures in the STP topology and it allows a blocking port to be held in a standby state.
What is uplink fast?
This port transports traffic to and from only the specified VLAN allotted to it. It will not deliver exclusive identifying tags because the VLAN intended for it is pre-assigned.
What is the access port?
The multistep convergence process to building the STP topology include:
What are:
1. A Root Bridge is elected
2. Root ports are identified
3. Designated ports are identified
4. Ports are placed in a blocking state as required, to eliminate loops
Technically, this is the fifth STP port state and in this state, the port has been administratively shutdown.
What is disabled?
How does RSTP define the four port roles?
What are:
1. Root Port-port on each switch that has the best path cost to the Root Bridge
2. Alternate Port-Backup root port that has a less desirable path cost
3. Designated Port-non-root port that represents the best path cost for each network segment to the Root Bridge
4. Backup Port-Backup designated port that has a less desirable path cost
This is a Cisco proprietary protocol for the interconnection of multiple switches and maintenance of VLAN information as traffic goes between switches.
What is 802.1Q?