Since the introduce of Power over Ethernet (PoE) technology, PoE LAN switch has become popular among wide users. However, newbies are usually confused with the multiple port configuration on gigabit PoE switch. Since there are already regular PoE Ethernet ports for powered devices (PDs), what are the function of other ports like console port, SFP/SFP+ port and combo port on gigabit PoE switch? This article will take 8 port PoE switch, 24 port PoE switch and 48 port PoE switch as example to illustrate multiple port for your reference.
Like regular Ethernet switch, gigabit PoE switch often has one built-in serial console port, say FS S1130-8T2F 8 port PoE switch. It is the port for controlling and managing switch since there are no display device for a switch. Usually console port on gigabit PoE switch is an RJ45 receptacle. To connect a computer directly to the 8 port PoE switch, one should use dedicated rollover cable rather than Ethernet cable for connection.To use console port, you need physical access to the appliance. Therefore for terminals without serial console port, one should attach a corresponding adapter to the devices before cabling.
Figure 1: A display of one console port on FS S1130-8T2F 8 port PoE switch for control.
RJ45 port on gigabit PoE switch is the regular PoE port to achieve data and DC power transmission for PDs. It is an auto-sensing 10/100/1000Mb copper port supporting only Ethernet cable (Cat5e/6/6a/7) for connection. Thus RJ45 port connection is limited to 1G speed and 100m (330ft) short distance transmission. Then how about longer distance transmission scenario?
Different from RJ45 port, SFP port on gigabit PoE switch has the opt of both short and long reach. Why? The mini GBIC port has inherited the compatibility of either copper or optical SFP connection. Provided you employ the corresponding SFP module and cable on power over Ethernet switch. For long distance transmission, you should use fiber SFP modules with fiber patch cable for optical link. For short distance, you can opt to use RJ45 SFP module with copper network cable on gigabit PoE RJ45 switch for electrical link. Gigabit PoE switch often provides 2 SFP port for optical connection or uplink aggregation requirement, which enhances network adaption resiliency of PoE powered switch. For instance, S1400-24T4F 24 port PoE switch has 2 SFP ports reserved, which caters for fiber uplink to upper layer switch.
Figure 2: A display of RJ45 ports vs SFP ports on FS gigabit PoE switch.
To illustrate SFP+ port on PoE Ethernet switch, we’ll take S1600-48T4S 48 port PoE switch as example. This 48 port PoE gigabit switch comes with 1 console port, 48 PoE+ RJ45 ports and 4 SFP+ ports. The 48 RJ45 ports are PoE ready to power on dozens of VoIP phones, IP cameras and wireless APs. The 4 SFP+ ports on gigabit PoE switch serves as uplink to connect 10G SFP switch for uplink aggregation.
Figure 3: Deploying S1600-48T4S 48 port PoE switch as gigabit access switch to link 10G SFP switch via SFP+ ports, and connect PDs.
Though manufactures often clearly label combo ports on gigabit PoE switch for identification, many people don’t know its function. Take S1400-24T4F 24 port PoE switch as example, 2 combo ports are reserved on this 24 port PoE managed switch. The combo port compounds RJ45 and SFP front ends in one single interface, thus it supports either copper or optical SFP link. However, you cannot use these two physical accesses on PoE network switch simultaneously. That is, once you activate combo SFP port on gigabit PoE switch, you also disable the opposite copper port.
Figure 4: A demonstration of combo ports on gigabit PoE switch: S1400-24T4F 24 port PoE switch from FS.COM.
To sum up, multiple ports on gigabit PoE switch owns different functionality, which enhances switching resiliency for different network cabling. RJ45 port on PoE powered switch is an normal one for copper link to PDs. SFP port of gigabit PoE switch provides options of fiber cabling or copper cabling due to fiber SFP module and RJ45 SFP module compatibility. 10G SFP+ port on 48 port PoE switch serves as uplink port for link aggregation in network layer. Combo port compounds RJ45 and SFP interface in one single fabric on gigabit PoE switch. So it helps to extend flexibility of physical access through the network. For 8/24/48 port cheap PoE switch buying, you can find decent offer here with optimal port configuration.