1000BASE-T Switch with SFP Ports Interconnection Methods?

Updated on Jul 29, 2021 by

The technology for boosting network speed continues developing rapidly. It is essential to maintain both configuration flexibility and high port utilization for equipment deploying at the intersection of legacy copper and newly installed optical networks. 1000BASE-T Ethernet cables and 1000BASE-T copper SFP module emerged as the best way to optimize port-level flexibility and to ensure maximum port utilization. While connecting 1000BASE-T switch with SFP ports, should we connect the built-in ports on two switches directly via Ethernet cables, or using the SFP ports with a 1000BASE-T copper SFP module over the Ethernet cables to connect the two switches together? This is what we are going to discuss.

1000BASE-T SFP and 1000BASE-T Ethernet Cable

Before we go any further, let’s start with some basic knowledge related to 1000BASE-T (IEEE 802.3ab) and standard Ethernet cables. 1000BASE-T is a standard for Gigabit Ethernet over copper wiring. “T” means twisted-pair cable (e.g. the common Cat5/5e/6 cables). 1000BASE-T is Gigabit Ethernet that provides speeds of 1000 Mbps over four unshielded twisted pairs of cabling rated at Category 5 or above (like Cat5e and Cat6). 1000BASE-T allows a segment with a maximum length of 100 meters, which can be used in data centers for server switching, LANs, for uplinks from desktop computer switches or directly to the desktop for broadband application. It allows auto negotiation between 100Mbps and 1000Mbps. The most prominent feature of 1000BASE-T is that it enables users to maintain the existing copper cabling, instead of having to rewire with optical fiber. When referring to the types of 1000BASE-T copper SFP modules, there are generally three types provided by Cisco.

Part Number Cable Type Transceiver Type Connector Type Transmission Distance
GLC-T Cat5 SFP RJ45 100m
GLC-TE Cat5 SFP RJ45 100m
SFP-GE-T Cat5 SFP RJ45 100m

While use only 1000BASE-T Ethernet cables connecting two switches together to get 1 Gigabit Ethernet, Cat5e and Cat6 network cables are available. The details of each are presented in the following chart.

Category Shielding Max Transmission Speed (at 100 m) Max Bandwidth
Cat 5e Unshielded 1000 Mbps / 1 Gbps 100 MHz
Cat 6 Shielded or Unshielded 1000 Mbps / 1 Gbps 250 MHz

1000BASE-T Switch Connection: 1000BASE-T SFP or Ethernet Cable

Network upgrade within a data center or server room is a commonplace to catch up with the demand for higher speed applications. Thus migration to Gigabit Ethernet is imperative for at least two reasons: faster systems and faster backbones. It has the potential for low-cost products, freedom of choice in selecting products, interoperability, and backward compatibility. When connecting two 1000BASE-T switch with SFP ports to get Gigabit Ethernet, there exist two methods: making a connection via a 1000BASE-T Ethernet cable inserted in the built-in Ethernet ports on each switch, or using the SFP ports with a 1000BASE-T copper SFP module. Which approach is better? Is there any difference between them? Here we use the following case to explain it to you.

1000BASE-T Switch with SFP Ports Interconnection Methods

In this case, a UniFi Security Gateway and a UniFi Switch 8-150W should be connected together via 1000BASE-T Ethernet cable to achieve network upgrade. If we use 1000BASE-T SFP copper module, we should insert two copper modules respectively into the SFP ports on the two switches, and then employ a Cat5 Ethernet cable to make a connection between them. The other solution is more simple and straightforward: it takes the advantage of the built-in Ethernet ports on the switches, and inserting a standard Ethernet cable (Cat5/5e/6/6a) directly to connect the two switches.

How to Choose Between Them?

The two methods generally deliver the same speed on the network, and the built-in port is doing exactly the same thing that a SFP module using copper wiring would be doing. If your 1000BASE-T switch has both built-in Ethernet ports and SFP ports, either of the two approaches makes sense. But considering the 1000BASE-T copper SFP module would generate extra costs and increase installation time, it is recommended to use standard Ethernet cables to make the connection. However, the SFP ports on the switch still exist for a reason—the SFP modules inserted in the ports are for cases where you need to connect between an all-SFP distribution switch and an all-copper edge switch. The reason the switches have SFP slots is to support connecting to a fiber optic network, either to talk to other fiber optic gear or especially to connect over distances that copper transmission can’t support at gigabit speeds.


While upgrade your network to 1000Mbps Gigabit Ethernet or 10 Gigabit Ethernet, whether use 1000BASE-T/10GBASE-T SFP/SFP+ module or standard Ethernet cable to connect two switches depending on the switches you are dealing with. For 1000BASE-T switches with built-in Ethernet ports and SFP ports, it is suggested to use the built-in Ethernet ports unless you need all of them for other devices. And save the SFP ports for possible connection to an optical network for longer distance transmission. As for connecting a switch with SFP ports to a switch only with Ethernet ports, a 1000BASE-T SFP or 10GBASE-T copper module should be inserted into the SFP port, then connecting the SFP copper module with the Ethernet ports on the other switch via a Ethernet cable.

Related Article: How to Use 10GBASE-T Switch to Build Spine-Leaf Network?

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