What is a switch?

The switch is a multi-port device, the Layer 2 switch is used for fast forwarding of data frames, and the Layer 3 switch also has the routing function. The switch has a backplane bus with a large bandwidth, and each port forwards data frames through the bus. Switch interfaces are mainly divided into two types: management interface and Ethernet interface. The management interface is used for device configuration, and the Ethernet interface is used for device or network access. Ethernet interfaces usually include 10M/100M/1000M/10G interfaces, which can be on the mainboard or on an independent interface module.

1. Equipment introduction

Taking the switch H3C S5820V2-48S as an example, the device is positioned for high-density access in next-generation data centers and cloud computing networks, and can also be used for the core or aggregation of enterprise networks and metropolitan area networks. The front panel is shown in Figure 1. The switch supports -48~-60V DC power modules, or 100~240V AC power modules. The switch has a fixed configuration of 48 SFP Plus/FCoE interfaces to provide 48 10M/100M/1000M Ethernet interfaces. At the same time, the switch has a Console port, a management Ethernet port and a USB port. The switching capacity of the switch is 1280Gbit/s, and the packet forwarding rate is 720Mpps, which can realize fast forwarding of data.

The size of the S5820V2-48S is 440mm x 460mm x 43.6mm. It is installed in a 19-inch cabinet through mounting ears and slides. The mounting ears and slides are shown in Figure 2.

 What is a switch?
Figure 1 – S5820V2-48S front panel
What is a switch?
Figure 2 – Mounting ears and slides

2. Introduction to the interface module

The S5820V2-48S has 48 SFP ports with fixed configuration, which can only be used after inserting an SFP module. The following introduces two typical SFP modules.

The SFP-GE module is an electrical port optical module. This module is used in conjunction with the SFP Plus/FCoE interface of the switch, and is directly inserted into the SFP Plus/FCoE interface to provide users with an Ethernet optical interface with a rate of 1000Mbit/s. The transmission medium is Category 5 unshielded twisted pair, the transmission distance is 100m, and the RJ-45 connector is used, which is only suitable for small-scale networking environments.

SFP-GE-LX is a Gigabit SFP optical module. The optical module is used for the transmission of optical signals, the transmission medium is optical fiber, and the LC connector is used. The optical fiber transmission method has low loss, and the transmission distance can reach up to 10km, which is very advantageous in long-distance transmission.