Differences between the RJ45 port and the SFP port of the switch
2017-07-04

We know that in the present market, Gigabit Ethernet switches generally have two ports: RJ45 port and SFP port, both of which can be transmitted with Gigabit Ethernet. Then what are the differences between the two ports? How should we wire them respectively? This tutorial will answer one by one.

Gigabit Ethernet switch’s RJ45 port and SFP port

In order to meet the growing network needs, network upgrade in the machine room of the data center or server is urgent. Therefore, Gigabit Ethernet has become increasingly common. So, what kind of port Gigabit switch should be used to achieve Gigabit Ethernet connection? The following is the introduction to two ports in detail:

RJ45 port

Gigabit Ethernet switch’s RJ45 port is a built-in port. To connect two RJ45 port Gigabit Ethernet switches, we only need to use a super five or six cable. The following table is the specific rate and bandwidth of this connection:

 

 

Shielded level

Maximum transfer ratedistance of 100m

Maximum bandwidth

Cat5 network cable

Unshielded

1000 Mbps / 1 Gbps

100 MHz

Cat6 network cable

Shielded or unshielded

1000 Mbps / 1 Gbps

100 MHz

SFP port

Gigabit Ethernet switch’s SFP port is in line with 1000BASE-T (IEEE 802.3ab) standard with the transmission rate of 1000 Mbps. Unlike the above RJ45 port, the SFP port of the switch must be inserted into the SFP optical module first, and then the network cable (Category 5 / Category 5 / Category 6 cable) must be used for data transmission. In addition, in the data center, local area network (LAN) and other applications, the switch’s SFP port also has 100 / 1000Mbps adaptive function. The following table is the specific situations of the SFP port:

 

Optical module type

Optical module interface

Transmission distance

Maximum transfer ratedistance of 100m

Cat5 network cable

SFP optical module with electrical port

RJ45

100m

1000 Mbps / 1 Gbps

Fiber jumper

SFP optical module with optical port

LCduplex

100m

1000 Mbps / 1 Gbps

 

RJ45 connection and SFP connection of Gigabit Ethernet switch 

The following figure shows the RJ45 connection and SFP connection of the Gigabit Ethernet switch. The left side is the SFP connection of the UniFi switch and the RJ45 connection is on the right side of the UniFi switch. SFP connection requires the use of two SFP electrical modules and a Cat5 cable or the use of two SFP optical modules with optical port and a fiber jumper; RJ45 connection only needs to use a Cat5 cable.

SFP-connection-and-RJ45-connection

Which is better?

From the above, RJ45 port and SFP port’s performance is basically the same, but from the cost, SFP port’s cabling costs are higher. However, the SFP port is still necessary because it supports both SFP optical modules with electrical ports and optical ports. The transmission distance of the latter is much longer than that of the RJ45 port. In the practical application, it has relatively high flexibility and scalability.



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