Shulou(Shulou.com)06/03 Report--

Knowledge point carding

Generation of switched Network Loop

The formation of a broadcast storm

Multi-frame replication

The MAC address table disorder spanning tree algorithm is divided into three steps.

Select the root bridge (Root Bridge)

Select the root port (Root Ports)

Select the designated port (Designated Ports) root bridge

Responsible for forwarding data between different switches, with only one root bridge

According to: compare priority first, compare MAC address root port in the same case

Elected on a non-root bridge, there is only one root port designated port on a non-root bridge

There is a designated port on each link, which can either receive data or send data root bridges responsible for forwarding data bridges ID (BID) in different switches.

Bridge ID is unique

Selecting the switch with the smallest ID of the bridge in the switched network becomes the basis for selecting the root port of the root bridge.

The lowest root path cost to the root bridge

The directly connected bridge ID is the smallest

Relationship between minimum bandwidth of Port ID and path cost

Link bandwidth (Mbps) path cost

10 100

16 62

45 39

100 19

155 14

622 6

1000 4 path cost

The sum of the costs of all links on the path from the bridge to the root bridge the ports on the root bridge are all designated ports on each network segment, select a designated port other than the designated port on the root bridge, and select the order

The root path cost is lower.

The value of the bridge ID of the switch is small

The value of the port ID is small BPDU

Bridge Protocol Data Unit-Bridge Protocol data Unit

Use Multicast to send BPDUBPDU types

Configure BPDU

Topology change Notification (TCN) BPDUBPDU report text field

Root bridge ID, root path cost, send bridge ID, port ID STP status of switch port

The use of form

Forward (Forwarding) send / receive user data

Learning (Learning) to build bridge table

Listening to build an "active" topology

Blocking receives only BPDU

Disable (Disabled) force the timer of STP to be turned off

Significance of Hello time, forwarding delay, maximum Aging time PVST+ configuration

Configure the more stable switch in the network as the root bridge

Using PVST+ to realize Network load sharing enable spanning Tree Command

Switch (config) # spanning-tree vlan vlan-list specifies the root bridge

Switch (config) # spanning-tree vlan vlan-list priority Bridge-priority

Switch (config) # spanning-tree vlan vlan-list root {primary | secondary} modify port cost

Switch (config-if) # spanning-tree vlan vlan-list cost cost modifies port priority

Switch (config-if) # spanning-tree vlan vlan-list port-priority priority configure Fast Port

Switch (config-if) # spanning-tree portfast to view the configuration of spanning tree

Switch#show spanning-tree

View spanning tree details for a VLAN

Switch#show spanning-tree vlan vlan-id detail

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