Shulou(Shulou.com)06/01 Report--

I. function

1.MAC address learning

two。 Confirm frame forwarding and filtering

3. Prevent loop

Second, the mode of frame switching

1. Pass-through forwarding: forward immediately after the switch detects the destination address

Fast forwarding switching, small delay, no error correction, sending error packets, the delay in pass-through forwarding is the time it takes to receive this bit to send this bit.

two。 Store-and-forward: the frame is fully received and picketed before forwarding.

The entire frame needs to be accepted before forwarding, and then the switch reads the destination address and the original address

3. No fragment forwarding: the switch detects the first 64 bytes of frame forwarding after

First filter the conflict domain, which is less than 64 bytes, and filter most errors

Advantages and disadvantages

No error correction check for cut-through fast forwarding

Storage filters out all errors, low efficiency, high latency, and the larger the frame, the slower the forwarding

No fragment in the middle

III. Orders

Global mode: no ip domain-lookup turns off domain name resolution

Line console 0 enters the console

Login save / passwd xxx

(config-line) # logging synchronous synchronizes with the console

Exec-timeout never times out.

Global: enable secret 000ciphertext

Service passwd-encryption all password encryption

Switchport mode access turns the interface into full-duplex mode

-Note: for every device, we should set synchronization with the console before configuring it, and never time out.

Turn off domain name resolution to improve our efficiency

IV. VLAN

It can be divided into up to 1024 VLAN and 23 VLAN in engineering.

VLAN can separate collision domain from broadcast domain

1. Each logical VLAN is like a separate switch.

two。 The same VLAN can span multiple switches

3. Backbone function can support data from multiple VLAN

4. Backbone functions distinguish different VLAN through special encapsulation.

5. VTP

1. A system that can announce VLAN configuration information

two。 Maintain the consistency of VLAN configuration information through a common management domain

3.vtp can only announce VLAN configuration information at the trunk port.

4. Backbone connections that support mixed media

VI. Working principle of VTP

1.VTP message announcement is carried out by broadcast

2.VTP server and client mode synchronization of the latest version of the information announcement

3.VTP message announcement is announced every five minutes or when there is a change

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