Difference between revisions of "CCNA Explorer 3 STP"

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|[[Image:ScreenShot142.jpg|800px|left|thumb|Loops int the cubicles]]
 
|[[Image:ScreenShot142.jpg|800px|left|thumb|Loops int the cubicles]]
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==Introduction to STP==
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===The Spanning Tree Algorithm===
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{|
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|[[Image:ScreenShot143.jpg|800px|left|thumb|STP Topology]]
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|[[Image:ScreenShot144.jpg|800px|left|thumb|STP Redundancy]]
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|-
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|[[Image:ScreenShot145.jpg|800px|left|thumb|STP Port names]]
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'''Root ports''' - Switch ports closest to the root bridge.<br/>
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'''Designated ports''' - All non-root ports that are still permitted to forward traffic on the network.<br/>
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'''Non-designated ports''' - All ports configured to be in a blocking state to prevent loops.
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|[[Image:ScreenShot146.jpg|800px|left|thumb|Root Bridge]]
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|[[Image:ScreenShot147.jpg|800px|left|thumb|BID fields]]
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|[[Image:ScreenShot148.jpg|800px|left|thumb|Port cost]]
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|[[Image:ScreenShot149.jpg|800px|left|thumb|Configuring port costs]]
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|[[Image:ScreenShot150.jpg|800px|left|thumb|Path Cost]]
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|[[Image:ScreenShot151.jpg|800px|left|thumb|Verify port and path costs]]
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===STP BPDU===
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{|
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|[[Image:ScreenShot152.jpg|800px|left|thumb|BPDU Fields]]
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'''Version''' - The version field indicates the version of the protocol, This field contains the value zero.<br/>
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'''Message type''' - The message type field indicated the type of message, this field contains the value zero.<br/>
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'''Flags''' - The flags field includes one of the following: Topology change(TC) bit, which signals a topology change in the event a path to the root bridge has been disrupted. Topology change acknowledgment(TCA) bit, which is set to acknowledge receipt of a configuration messege with the TC bit set.<br/>
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'''Root ID''' - The Root ID field indicates the root bridge by listing its 2-byte prority followed by its 6-byte MAC address ID.<br/>
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'''Bridge ID''' - The Bridge ID field indicates the priority and MAC address ID of the bridge sending the message<br/>
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'''Port ID''' - The Port ID field indicates the port number from which the configuration message was sent.<br/>
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'''Forward Delay''' - The Forward delay field indicates the length of time that bridges should wait before transitioning to a new state after topology change.
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|[[Image:ScreenShot154.jpg|800px|left|thumb|BPDU Fields]]
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|[[Image:ScreenShot155.jpg|800px|left|thumb|BPDU Process Step 1]]
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|[[Image:ScreenShot156.jpg|800px|left|thumb|BPDU Process Step 2]]
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|-
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|[[Image:ScreenShot157.jpg|800px|left|thumb|BPDU Process Step 3]]
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|[[Image:ScreenShot158.jpg|800px|left|thumb|BPDU Process Step 4]]
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|[[Image:ScreenShot159.jpg|800px|left|thumb|BPDU Process Step 5]]
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|[[Image:ScreenShot160.jpg|800px|left|thumb|BPDU Process Step 6]]
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|[[Image:ScreenShot161.jpg|800px|left|thumb|BPDU Process Step 7]]
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|[[Image:ScreenShot162.jpg|800px|left|thumb|BPDU Process Step 8]]
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|-
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|[[Image:ScreenShot163.jpg|800px|left|thumb|BPDU Process Step 9]]
 
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Revision as of 13:30, 24 August 2010

STP

Redundant Layer 2 Topologies

Redundancy

Simple network VLAN mangement
Starting point
Path Failure - Access to Distribution
Path Failure - Distribution to Core
Switch Failure - Distribution layer
Switch Failure - Core layer

Issues with Redundancy

Layer 2 Loops
Broadcast loops

Real-world Redundancy Issues

Non-Redundant network topology
Loops from 2 connections in the same switch
Loops from connections to a second switch
Loops int the cubicles

Introduction to STP

The Spanning Tree Algorithm

STP Topology
STP Redundancy
STP Port names

Root ports - Switch ports closest to the root bridge.
Designated ports - All non-root ports that are still permitted to forward traffic on the network.
Non-designated ports - All ports configured to be in a blocking state to prevent loops.

Root Bridge
BID fields
Port cost
Configuring port costs
Path Cost
Verify port and path costs

STP BPDU

BPDU Fields

Version - The version field indicates the version of the protocol, This field contains the value zero.
Message type - The message type field indicated the type of message, this field contains the value zero.
Flags - The flags field includes one of the following: Topology change(TC) bit, which signals a topology change in the event a path to the root bridge has been disrupted. Topology change acknowledgment(TCA) bit, which is set to acknowledge receipt of a configuration messege with the TC bit set.
Root ID - The Root ID field indicates the root bridge by listing its 2-byte prority followed by its 6-byte MAC address ID.
Bridge ID - The Bridge ID field indicates the priority and MAC address ID of the bridge sending the message
Port ID - The Port ID field indicates the port number from which the configuration message was sent.
Forward Delay - The Forward delay field indicates the length of time that bridges should wait before transitioning to a new state after topology change.

BPDU Fields
BPDU Process Step 1
BPDU Process Step 2
BPDU Process Step 3
BPDU Process Step 4
BPDU Process Step 5
BPDU Process Step 6
BPDU Process Step 7
BPDU Process Step 8
BPDU Process Step 9