Chapter 2 section_3 Flashcards
what type of BPDU’s does the RSTP use and what version?
type 2 version 2
what type of BPDU’s does the STP use and what version?
type 0 and version 0
the RSTP sends out a BPDU every ____ with its info? the BPUD’s are used as keep-allives so that the connection is not marked as down.
hello interval (2 seconds)
when using RSTP how is the protocol information aged? what must take place?
the RSTP switch must miss or not receive 3 hello packets (six seconds). or max age timer must expire.
what are Edge Ports?
An RSTP edge port is a switch port that is never intended to be connected to another switch. It immediately transitions to the forwarding state when enabled.
what is the portFast feature on the RSTP edge ports?
this allows these ports (will never connect to another switch and only to end devices) to automatically turn into the forwarding state skipping the listening and learning state. *this is much faster.
what is the link type: point-to-point?
A port operating in full-duplex mode typically connects a switch to a switch and is a candidate for a rapid transition to a forwarding state
what is the link type: shared?
A port operating in half-duplex mode connects a switch to a hub that attaches multiple devices.
what type of link state allows a designated port to rapidly change to the forwarding state?
if the link-type parameter is set to point-to-point
*the link type can be manually set using the command: ‘spanning-tree link-type’
otherwise it depends on if the connection media is half or full duplex. full duplex is point to point and half duplex is shared media (connects to a hub and several end devices)
which type of PVST can do the following?
port roles: root, designated, alternate, edge and backup.
**ports can transition to forwarding without relying on a timer.
Rapid PVST+
what are the spanning tree port costs for the following speeds? 1000mb/s
100mb/s
10 mb/s
1000mb/s = 4
100 mb/s = 19
10 mb/s = 100
*lower cost is better
what are the 2 methods to set the Bridge ID on a switch? so that you can make certain switches the primary and secondary root switch.
method 1: command: ‘spanning-tree vlan (vlan-id) root primary’ or ‘secondary’ ::: this sets the value at 24,567 or 4,096 less than the lowest BID on the network.
method 2: command “spanning-tree vlan (vlan-id) priority (value)” a value of 0 will make it the primary root switch.
what is BPDU guard and why use it?
it is used on portfast ports on a switch. these ports should only be connected to access devices and not other switches. this means that BPDU’s will/ should not be sent to this port b/c only BPDU’s are sent from STP switches. if a BPDU does come to the port then the port shutsdown and must be re-enabled manually… the BPDU guard is responsible for shutting this port down and it is done to stop invalid configurations (BPDU’s)
if you use the command: # show spanning-tree vlan 10
and u get the output below, what spanning tree protocol is running?
**
vlan 10
spanning tree enabled protocol rstp
the Rapid PVST+ is running
this means that the per vlan spanning tree protocol is running and it is the cisco version Rapid Spanning Tree Protocol that is running on this particular vlan.
what is a FHRP?
Forward Hop Redundancy protocol
this is when a network has multiple routers/ layer 3 switches configured as the default gateway under a virtual ip and mac address. if the active/ forwarding router fails then the standby router becomes the forwarding router. the access devices do not see a change in ip or mac address.
