Analysis of simple layer-3 Switch configuration and maintenance methods

This article briefly introduces the composition of a layer-3 Switching Network and the responsibilities of each layer. Cisco layer-3 switch is a typical layer-3 Switching Network, which has three levels: access layer and aggregation layer, core layer.

The access layer configured by the Cisco layer-3 Switch, as its name implies, is the first device to connect a terminal device to a LAN, and is the device closest to a user's computer, the configuration devices of the layer-3 Cisco switch have the following features:

◆ Port intensive

◆ Interface status changes frequently

◆ Low unit traffic

◆ There are many access policies

◆ Layer-2 loops exist

The preceding configurations are characteristic of the layer-3 Cisco switch. Generally, the access layer switches have 24 ports and 48 ports, which are stacked because the user group is quite large. Generally, the access layer switch port is maintained at 10/100 self-negotiation, and the maximum value is 100. This ensures the transmission speed of devices in different segments, therefore, the port status of the access layer switch is often repeated between UP and DOWN.

Not suitable for STP Spanning Tree Protocol. In the face of users, the access layer switch has too many policy restrictions, such as VLAN. Generally, the access layer switch is bound to the aggregation layer with port 100 of Port 2 as the Ethernet channel Trunk.

Cisco L3 Switch configuration aggregation layer this layer is the place where the traffic of switches in the access layer is set. All access layer switches connect to the aggregation layer switches through various expressconnect channels. The Cisco layer-3 Switch has the following features:

◆ The number of ports is sparse compared with that of access layer Switches

◆ The speed of port exchange per unit is much higher than that of the access layer switch

◆ Data forwarding must be ensured at high speed without obstruction

◆ The port status is solid, and the switchover is almost nonexistent.

◆ Many aggregation layer switches are L3 Devices

Generally, aggregation layer switches have fewer ports, but generally all are Gigabit ports, which are used to accept traffic at the access layer. In addition, the data forwarded at this layer is basically "pure ", therefore, it is necessary to ensure high-speed data forwarding. Because it is a convergence layer, the port overwriting status of this layer is almost never met. Unless a access layer switch is damaged, a medium aggregation layer switch generally has a three-layer function, you can configure access-list to further limit illegal traffic. Is a very suitable STP root.

Cisco L3 Switch configuration core layer:

The devices at this layer are large devices that ensure high-speed and no-fault data forwarding, including routing. The Cisco L3 switch has the following configuration features:

◆ High cost

◆ Layer-3 Functions

◆ Under normal circumstances, no port overwrites

◆ Forwarding Routing) fast

◆ Some core layers undertake the LAN access to the outside

The main purpose of the Cisco layer-3 Switch configuration is to summarize the data and forward it as quickly as possible. Therefore, you cannot configure any configuration that hinders or filters data packets at this layer. Generally, there is no loop.

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2. Summarize the market status of high-end Switches
3. Focuses on core layer switch faults
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5. Let's talk about the stacking of Ethernet switches.