ARP table Mac table route table

An ARP table is a dynamic table stored in a computer. It is used to correspond an IP address to a MAC address.
Assume that computer A communicates with computer B in the same subnet segment.
Computer A's IP address 192.168.0.1 MAC address AA-AA-AA-AA-AA-AA
IP address of computer B known 192.168.0.2 MAC Address Unknown
Then computer A will initiate an ARP query. "Who can tell me what the MAC address of 192.168.0.2 is ?"
Obviously, when a vswitch is used, the vswitch cannot understand the IP address. to broadcast this information, send the query information to all other ports except the sender. (Of course, the switch must remember the MAC address of the host 192.168.0.1)
When all other computers see that this broadcast finds that the destination IP address is not their own, they will discard this data, only 192 .. 168.0.2 computer B will respond and send a receipt, telling computer a, "I'm 192.168.0.2, my mac address is AA-AA-AA-AA-AA-AB" when passing through the switch, the switch remembers the MAC address from computer B and uses the known MAC address of computer A to start the port connecting to computer. (Do not broadcast now) both computer A and computer B know the IP address and MAC address of the other party and start communication.
I believe some people already know the answer.

 

There must be an ARP table for a layer-3 Switch. There is no doubt that IP addresses are involved because of the routing function. You may have questions about whether layer-2 switches exist, generally, Layer 2 does not exist. The so-called ARP is the Address Resolution Protocol, while the IP address refers to the IP address being resolved to a MAC address. The Layer 2 and the IP address are not closed, so it is generally unavailable, however, when we configure a management VLAN, for example, int VLAN 1, and then IP add..., which is used for management, an ARP table is generated.

 

What is an ARP table! What is a MAC address table!
You have figured it out! The layer-2 switch has a MAC address table and no ARP table. There is an IP address in the ARP table, and the L2 device does not have an IP address. Therefore, L2 switches do not have ARP tables. There are Mac tables. Be sure to clarify.
Be sure to be rigorous when talking about academics! The definition must be clear, otherwise it is hard to say clearly!

There must be an ARP table for a layer-3 Switch. There is no doubt that IP addresses are involved because of the routing function. You may have questions about whether layer-2 switches exist, generally, Layer 2 does not exist. The so-called ARP is the Address Resolution Protocol, while the IP address refers to the IP address being resolved to a MAC address. The Layer 2 and the IP address are not closed, so it is generally unavailable, but when... [/quote] I agree that a layer-2 switch has a management VLAN, Which is disabled by default. If it is enabled, an ARP table is available.
ARP is an Address Resolution Protocol that enables direct access to MAC addresses through IP addresses.
I won't talk about how it works. The above explanation is very clear.
Each computer with [url =/View/7649.htm] [color = # 0000ff] TCP/IP Protocol [/color] [/url] has an ARP cache table, the IP addresses in the table correspond to [url =/View/69334.htm] [color = # 0000ff] MAC Address [/color] [/url] one by one.
We can enter ARP-A at the command prompt to view the ARP cache table of the local computer.
Which of the following parameters can be used? .
The ARP cache does not exist for a long time. The ARP cache table adopts an aging mechanism (that is, TTL is set). Within a period of time (generally 15 to 20 minutes) if a row in the table is not used, it will be deleted, which can greatly reduce the length of the ARP cache table and speed up the query.

Layer 2 devices only have the Port-to-Mac table
When a layer-2 switch is started, it will automatically detect the MAC addresses of the machines connected to its own port, thus forming a corresponding table such as Port-Mac.
ARP tables are available for Layer 3 devices ~

To put it simply, no one can say the ARP protocol. It is a layer-3 protocol, but it works on layer-2. Specifically, the switch has a MAC address table, when the host needs to be accessed by a layer-2 device, first look for its internal ARP cache table. If not, send a broadcast package containing the destination IP address, if the host with the corresponding IP address sees someone calling it, it will respond and send it back to the package. The package contains the MAC address of the local machine, which is put into the Mac table by the switch, the SVI mentioned by the brother on the 20th floor is a special case... Strictly speaking, it is not an ARP table. No one can say whether the ARP protocol is Layer 2 or Layer 3. Specifically, Layer 2 relies on Mac table forwarding, because the TCP protocol requires ACK, some ARP spoofing problems can also be caused.

To understand the forwarding principles and procedures, you must clarify the ARP table, switch forwarding table, and route table. This is the basis for data forwarding. Since the ARP table and switch forwarding table are transparent to administrators, they usually ignore their working principles. This is a learning point that I need to pay attention. So today we mainly understand ARP tables, switch forwarding tables, and route tables.

The final data forwarding relies on ARP tables, which are the most basic basis for data forwarding. ARP maps hardware addresses and network addresses directly.

Although the route table does not depend on the final data forwarding, the route table is a wizard that guides the data trend and enables the data to span the network. The ARP table has no mask and does not distinguish the network segments.

ARP table Mac table route table