As the network tends to develop at high speeds, 10 Gigabit switches are becoming more and more popular in enterprise networks. However, the compatibility issue between SFP and SFP+ has always puzzled many users. For example, can SFP+ ports support SFP optical modules? Can SFP ports support SFP+ optical modules? Can the SFP port of the Gigabit switch be connected to the SFP+ port of the 10 Gigabit switch? This article will reveal the compatibility issues of SFP and SFP+ ports.
What is the SFP port on the Gigabit switch?
With the continuous changes in the transmission rate of Ethernet switches, the types of ports are also constantly changing, such as SFP ports, SFP+ ports, SFP28 ports, QSFP+ ports, QSFP28 ports, etc. The SFP port is a compact and hot-swappable network For the Ethernet interface, the transmission rate is 1Gbit/s, and for the fiber channel system, the transmission rate can reach 4Gbit/s. When inserting SFP optical modules with optical fiber jumpers or copper cables into the SFP ports of the gigabit switch, different distances can be transmitted. For example, the maximum transmission distance is 160 kilometers when the SFP1G-ZXC-55 optical module is connected with the LC duplex fiber jumper, and the maximum transmission distance is when the SFP-GB-GE-T optical module (ie, electrical interface module) is connected with the five-category network cable. The transmission distance is 100 meters.
What is the SFP+ port on the 10 Gigabit switch?
10 Gigabit switches are divided into 10 Gigabit fiber switches and 10 Gigabit copper switches according to different port types. The 10 Gigabit fiber switches are 10 Gigabit switches with SFP+ ports. The appearance and size of the SFP+ ports and the above-mentioned SFP ports are The same, the biggest difference between the two is that the SFP+ port can support a transmission rate of up to 10Gbps. Generally speaking, 10 Gigabit switches will have higher-speed uplink ports, such as QSFP+ ports and QSFP28 ports, to facilitate the connection of other higher-speed switches in the topology.
In most cases, SFP optical modules can be used on SFP+ ports
Can a 1G SFP optical module be plugged into a 10G SFP+ port for use? In most cases, it is possible, but if you insert an SFP optical module into an SFP+ port, the transmission rate of the link will be reduced to 1Gb, and some switches will lock the port rate at 1G until you reset the switch or The port speed will be restored when the configuration command is executed. In addition, SFP+ ports generally cannot support rates below 1Gb. In other words, SFP+ ports cannot use 100BASE SFP optical modules. In fact, for this problem, a large extent depends on the switch itself, because some switches can support, but some cannot. At present, many 10 Gigabit switches provided by suppliers can insert 10G SFP+ optical modules and 1G SFP optical modules on SFP+ ports (but the two cannot be used at the same time), and some 10 Gigabit switches provided by suppliers can only support 10G SFP+ optical modules. Therefore, if you want to insert the SFP optical module into the SFP+ port of the 10 Gigabit switch, it is best to consult the supplier before using it to ensure that the SFP+ port of the 10 Gigabit switch can support dual rates.
In any case, SFP+ optical modules cannot be used on SFP ports
Can 10G SFP+ optical modules be used on 1G SFP ports? The answer is definitely "No". As we all know, the speed of the optical module installed on the switch determines the speed of the port link. At present, the SFP+ ports on most 10 Gigabit switches are backward compatible and support 1G SFP optical modules. However, the SFP port on the gigabit switch is not forward compatible, that is, it cannot support 10G SFP+ optical modules.
Can the SFP port of the Gigabit switch be connected to the SFP+ port of the 10 Gigabit switch?
As can be seen from the above, usually SFP+ ports can support SFP optical modules and SFP+ optical modules, while SFP ports can only support SFP optical modules but not SFP+ optical modules. Therefore, the two ends of the connection are mainly divided into the following two situations:
When the SFP+ optical module is used on the SFP+ port of the 10 Gigabit switch and the SFP optical module is used on the SFP port of the Gigabit switch, the SFP+ port of the 10 Gigabit switch cannot be connected to the SFP port of the Gigabit switch. Because the SFP+ optical module does not support auto-negotiation technology (auto-negotiation is based on electrical pulses instead of optical pulses, it can only be implemented on twisted-pair cables, not on optical fibers), the rate cannot be adjusted to 1G, this connection method is invalid .
When the SFP optical module is used on the SFP+ port of the Gigabit switch and the SFP optical module is used on the SFP port of the Gigabit switch, the SFP+ port of the Gigabit switch can be connected to the SFP port of the Gigabit switch. At this time, the link It can work normally, and its link transmission rate is 1G.
to sum up
All in all, most SFP+ ports can support SFP optical modules, but SFP ports cannot support SFP+ optical modules. When the 1G SFP optical module is inserted into the SFP+ port on the 10G switch, the rate of the 10G SFP+ port will be reduced to 1G, that is, the SFP+ port of the 10G switch can be connected to the SFP port of the Gigabit switch, but at this time The transmission rate of the link is 1G. Therefore, in order to ensure the normal operation of the network, the optical modules used at both ends must be compatible with each other.