Switch working principle and configuration

Ethernet switch category

2960 Series: entry-level switch

3560 series: enterprise-level switches.

4500 series: modular switches that support expansion.

6500 Series: high-end switches, mainly used for large enterprises and telecom China Netcom operators.

How a vSwitch works

1) learning

The vSwitch will view its MAC address table during forwarding. The address table contains the interface number corresponding to the target MAC address. If no source MAC address exists in the entry, the corresponding MAC address table is formed.

2) broadcast

If the switch does not find the entry corresponding to the target data frame in the MAC address table, it does not know which interface to forward the data. Broadcast is required at this time, for example, 00-00-00-00-00-00-00, where are you? At this time, the host that belongs to the same VLAN will receive this broadcast, and then will respond if I hear it.

3) unicast

At this time, the two of them have established a communication relationship and can directly send data to the other party without repeated broadcasts.

The default aging time of a vSwitch is 300 S. If the switch communicates with each other again during this period, it is reset to 300 S.

Switch function:

The main functions of a vSwitch include physical addressing, network topology, error verification, frame sequence, and traffic control. At present, the switch also has some new functions, such as support for VLAN (Virtual LAN), support for link aggregation, and even some also have firewall functions.

Learning: The Ethernet switch understands the MAC address of each port connected device, and maps the address with the corresponding port and stores it in the MAC address table in the switch cache.

Forwarding/filtering: when the destination address of a data frame is mapped to a MAC address table, it is forwarded to the port connecting to the target node rather than all ports (if the data frame is broadcast/multicast frame, it is forwarded to all ports ).

Eliminate loop: When a vSwitch includes a redundant loop, the Ethernet switch avoids loop generation through the Spanning Tree Protocol and allows a backup path. The main functions of a vSwitch include physical addressing, network topology, error verification, frame sequence, and traffic control. At present, the switch also has some new functions, such as support for VLAN (Virtual LAN), support for link aggregation, and even some also have firewall functions.

Learning: The Ethernet switch understands the MAC address of each port connected device, and maps the address with the corresponding port and stores it in the MAC address table in the switch cache.

Forwarding/filtering: when the destination address of a data frame is mapped to a MAC address table, it is forwarded to the port connecting to the target node rather than all ports (if the data frame is broadcast/multicast frame, it is forwarded to all ports ).

Eliminate loop: When a vSwitch includes a redundant loop, the Ethernet switch avoids loop generation through the Spanning Tree Protocol and allows a backup path.

Simply put, the main function of a vSwitch is to allow communication between the same broadcast domain!

The switch is single-handed, half-duplex, and full-duplex.

1) ticket

Data can only be transmitted in one way.

2) duplex

Data can be transmitted in two directions, but not at the same time.

3) full duplex

Data can be transmitted in two directions and at the same time.

Working mode mismatch: communication fails. Rate mismatch: severe packet loss.

Basic configuration command:

1) enable the privileged mode to view the configuration of the device. You can make some modifications.

2) configure terminal enters global mode and configures the entire switch.

3) inter fastethernet 0/1 enters the 0/1 interface and configures the interface

4) exit returns an end layer to the privileged mode.

CTRL + A move the cursor to the beginning of the line CTRL + E move the cursor to the end of the line

2. Common commands

1) hostname (host name) is used to configure the host name

2) show version

3) show mac-address-table View MAC address table

4) duplex {full half auto} indicates that the duplex mode of the interface is semi-automatic (specified in interface mode)

5) speed {10 100 1000 auto} specifies the interface speed

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Switch working principle and configuration