Shulou(Shulou.com)06/02 Report--

Lab name: switch MAC table formation

Lab requirements:

1. Make sure that PC-1 and PC-3 can Ping each other.

2. View the MAC address table of the switch

The steps of the experiment:

1. Interconnect the switch and PC-1/2/3; correspond to the Fas0/1/2/3 port of the switch

2. Configure the IP address of PC-1/2/3 (you can not configure the gateway IP address at this time)

3. Before Ping, check the MAC address table of the switch (empty)

4. After PC-1 ping PC-3, check the MAC address table of the switch

Process analysis:

PC1-- > PC3

192.168.1.1-> 192.168.1.3

A-> C

Detailed explanation of the principle:

1. The switch receives the data packet sent by PC1 at the Fas0/1 port.

Follow the source MAC address to form an MAC address table entry:

A-Fas0/1

2. The switch pays attention to the destination MAC address of the packet sent by PC1, and then looks up the table.

Target MAC: C

MAC address table: show mac-address-table

By default, the table is empty when you first turn it on

Match:

As a result-unsuccessful, so, broadcast

3. The switch sends PC1 packets from Fas0/2 and Fas0/3.

4. After the PC-2 connected to the Fas0/2 port receives the data packet, first check the destination MAC

Whether the address is the same as the address of your network card. If different, the packet is discarded

5. After the PC-3 connected to the Fas0/3 port receives the data packet, first check the destination MAC

Whether the address is the same as the address of your network card. If the same, continue to analyze the target IP

Address, if it is the same as your own IP address, then receive (otherwise, discard)

6. PC-3 builds a response message based on the received Ping request:

192.168.1.3-> 192.168.1.1

C-> A

And send it out.

7. When the switch receives the packet sent by PC-3 at the Fas0/3 port, first check the source

MAC to form an MAC address table entry:

C-Fas0/3

8. The switch pays attention to the destination MAC address of the packet sent by PC-3 and looks for MAC.

Address table: show mac-address-table

A-- Fas0/1

At this time, the destination MAC address of the packet is A, which happens to match the modified entry, then the packet is sent out the Fas0/1 port.

9. After PC-1 receives the data packet, it first analyzes whether the destination MAC address is the same as its own network card address. If it is the same, it continues to analyze whether the destination IP address is the same as its own IP address, and if it is the same, it receives it. The Ping display is successful.

Summary:

1. Tabulated-View Source MAC

2. Look up the table-view the target MAC

3. The dynamic entries of the MAC table have a certain survival time, and the default value is 300s.

4. The size of the MAC table has a certain space (show mac-address-table)

A small expansion:

When a PC configures an IP address, the device first sends an unprovoked ARP for detection

Whether the configured IP address is available (make sure there are no duplicate IP addresses in this network segment)

Unprovoked ARP request message:

Source MAC-> destination MAC

E-> full F; (represents a broadcast MAC address)

1. After the switch receives the unprovoked ARP sent by PC-4 at the Fas0/4 port

First, check the source MAC address of the message to form an MAC address table entry:

E-Fas0/4

2. Secondly, the switch looks at the destination MAC address of the packet and makes a MAC address table.

Matching of entries:

Minor problems:

Whether there is an entry corresponding to all F in the MAC address table

For example: full F-Fas0/10

Answer: does not exist!

The switch can isolate the collision domain, not the broadcast domain

Routers can isolate broadcast domains, can isolate collision domains

ARP: IP-MAC

MAC address table: MAC-Port

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