All Cisco-Network Study Notes: Foundation Arbitrary-Protocols and Standards-IEEE 802.1d STP Timers

Foundation Arbitrary

Foundation Summary

This area lists added capacity and facts to annular out the advantage of the capacity in this chapter.

Unlike best of the Cisco Press Assay Certification Guides, this “Foundation Summary” does not

repeat advice presented in the “Foundation Topics” area of the chapter. Please booty the

time to apprehend and abstraction the capacity in the “Foundation Topics” area of the chapter, as able-bodied as

review items acclaimed with a Key Topic icon.

Table 3-11 lists the protocols mentioned in this affiliate and their corresponding standards documents.

Table 3-11 Protocols and Standards for Affiliate 3

Table 3-12 lists the three key timers that appulse STP convergence.

Table 3-12 IEEE 802.1d STP Timers

Table 3-13 lists some of the key IOS commands accompanying to the capacity in this chapter. (The command

syntax for about-face commands was taken from the Catalyst 3550 Multilayer About-face Command

Reference, 12.1(20)EA2.) Also accredit to Table 3-5 for several added commands.

Name Standards Body

RSTP IEEE 802.1w

MST IEEE 802.1s

STP IEEE 802.1d

LACP IEEE 802.1AD

Dot1Q trunking IEEE 802.1Q

PVST+ Cisco

RPVST+ Cisco

PagP Cisco

Timer Default Purpose

Hello 2 sec Interval at which the basis sends Hellos

Forward

Delay

15 sec Time that about-face leaves a anchorage in alert accompaniment and acquirements state; also

used as the abbreviate CAM abeyance timer

Maxage 20 sec Time after audition a Hello afore assertive that the basis has failed

86 Affiliate 3: Spanning Tree Protocol

Table 3-13 Command Reference for Affiliate 3

Command Description

spanning-tree approach {mst | pvst |

rapid-pvst}

Global config command that sets the STP mode

[no] spanning-tree vlan x Enables or disables STP central a accurate VLAN when

using PVST+

spanning-tree vlan vlan-id {forward-time

seconds | hello-time abnormal | max-age

seconds | antecedence antecedence | {root {primary

| secondary} [diameter net-diameter

[hello-time seconds]]}}

Global config command to set a array of STP

parameters

spanning-tree vlan x amount y Interface subcommand acclimated to set interface costs,

per VLAN

spanning-tree vlan x port-priority y Interface subcommand acclimated to set anchorage priority, per

VLAN

channel-group channel-group-number

mode {auto [non-silent] | desirable

[non-silent] | on | alive | passive}

Interface subcommand that places the interface into a

port channel, and sets the agreement parameters

channel-protocol {lacp | pagp} Interface subcommand to ascertain which agreement to use

for EtherChannel negotiation

interface port-channel port-channelnumber

Global command that allows agreement of

parameters for the EtherChannel

spanning-tree portfast Interface subcommand that enables PortFast on the

interface

spanning-tree uplinkfast Global command that enables UplinkFast

spanning-tree backbonefast Global command that enables BackboneFast

spanning-tree mst instance-id priority

priority

Global command acclimated to set the antecedence of an MST

instance

spanning-tree mst agreement Global command that puts user in MST configuration

mode

show spanning-tree basis | abrupt | arbitrary EXEC command to appearance assorted capacity about STP

operation

show spanning-tree uplinkfast |

backbonefast

EXEC command to appearance assorted capacity about

UplinkFast and BackboneFast

Memory Builders 87

Memory Builders

The CCIE Routing and Switching accounting exam, like all Cisco CCIE accounting exams, covers a fairly

broad set of topics. This area provides some basal accoutrement to advice you exercise your anamnesis about

some of the broader capacity covered in this chapter.

Fill in Key Tables from Memory

Appendix E, “Key Tables for CCIE Study,” on the CD in the aback of this book contains abandoned sets

of some of the key arbitrary tables in anniversary chapter. Print Appendix E, accredit to this chapter’s tables

in it, and ample in the tables from memory. Accredit to Appendix F, “Solutions for Key Tables for CCIE

Study,” on the CD to analysis your answers.

Definitions

Next, booty a few moments to address bottomward the definitions for the afterward terms:

CST, STP, MST, RSTP, Hello timer, Maxage timer, Forward Delay timer, blocking state,

forwarding state, alert state, acquirements state, disabled state, alternating state, discarding

state, advancement state, Basis Port, Designated Port, above BPDU, PVST+, RPVST+,

UplinkFast, BackboneFast, PortFast, Basis Guard, BPDU Guard, UDLD, Loop Guard,

LACP, PAgP

Refer to the CD-based comment to analysis your answers.