spanning-tree application Block 4_1b

STP

RSTP is backwards compatible with _____

backup port

assigned role as a backup to designated port for a shared LAN segment less common assigned role in RSTP

RSTPP: discarding, learning, forwarding STP: blocking, listening, learning, forwarding

RSTP vs STP port states

root bridge

RSTP will designate a switch in the topology as the _____

1. discarding - state for switchport that thinks loop will exist on a network should the switchport be allowed to forward frames. frames generate by nodes on a network recieved by this will not be forwarded but thrown out 2. learning - state for switchport that is unable to forward frames with data from network nodes but will populate MAC address table with the source MAC address of frames recieved on the interface assigned to 3. forwarding - state for switchport considered to be in normal operation. able to recieve and forward node generate frames that contain data on a network

RSTP's 3 port states

alterante port; designated port

_____ will enter a discarding state and the other side of the alternate port link will go into a _____ role

designated ports

assigned role to all ports in a forwardimg state on root bridge

root ports

assigned role to all ports in a forwarding state on NON-root bridge

alternate port

assigned role to the second-best link to the root bridge - extra step that STP doesn't do

portfast

command assigned to access switchports on a Cisco switch - allows switchport to bypass the learning state and go to forwarding state - should only be configured on access swithcports to prevent accidental loops on a network by bypassing the learning state

backbone fast

command assigned to trunk switchport on Cisco switch a CORE layer - default in RSTP & cannot be disabled

uplink fast

command assigned to trunk switchport on Cisco switch at ACCESS layer - default in RSTP & cannot be disabled - redundant link will transition into forwarding state and become new root port

RSTP: IEEE 802.1w & 10 milisecsresponse to failures STP: IEEE 802.1D & 30-50 sec response to failure and allow redundant switchports to transition to forwarding state

rapid spanning-tree protocol (RSTP) vs spanning-tree protocol (STP)

to disable redundant links to avoid loops on a network and the broadcast storms resulting from them

spanning-tree protocol

rapid spanning-tree protocol

streamline version of STP introduced as IEEE 802.1w and provides faster response to failures on a network

convergence

time it takes the spanning-tree protocol (STP) to repsond and transition links into a fowarding state to recover from link failure

one switch may run RSTP on a network another my use STP topology on same network by running STP

what does backwards compatibility mean?

allows switch to detect indirect link failures on neighboring switches in the STP topology and respond to undergo convergence

what happens when backbone fast is maunally enabled in STP?

allows trunk to quickly recover from a direct link failure

what happens when uplink fast is manually enabled in STP?

for the switchport to be able to transition into a forwarding state and become the new root port should the original fai;

what is the purpose of the alternate port role ins RSTP?

only observed when there is a connection to ta network hub somewhere on the network

why is backup port a less common RSTP role?

small accidental outages can both impact missiona and daily operations

why is slow convergennce response time problematic?