Core switch Fibre port-level connection mode and type

The port of the core switch is mainly a fiber type, but the price of the switch fibre port is very expensive and requires special attention from the user, while the fibre port of the switch is not stacked and can only be used for cascading purposes.

Cascading can use either a normal port or a special mdi-ii port. A pass-through cable should be used when the two ports that are cascaded are normal (that is, mdi-x) and Mdi-ii ports. You should use a crossover cable when each of the two ports that are cascaded are either normal (i.e. mdi-x) or are both mdi-ii ports.

Whether it is 10base-t Ethernet, 100BASE-TX Fast Ethernet, or 1000BASE-T Gigabit Ethernet, a cascade switch can have a cable length of 100 meters, which is exactly the same length as the core switch to the computer. Therefore, in addition to the ability to expand the number of ports, the other purpose is to quickly extend the network diameter. When there are 4 switches cascaded, the network span can reach 500 meters. Such distances are sufficient for small networks in the same building!

Using the uplink switch fibre port cascade now, more and more switches (except Cisco switches) provide a uplink port, making the connection between the core switches easier. The uplink port is a port that is specifically used to connect to other switches and can be connected to any port other than the uplink port of the other switch using a pass-through jumper.

This connection is identical to the connection between the computer and the switch. It should be noted that some brands of switches (such as 3COM) use a common port as a uplink port and switch between the two types using a switch (mdi/mdi-x switching switch). Use straight line through the uplink Port Cascade switch.

Use normal port Cascade

If the core switch does not provide a dedicated cascade port (uplink port), then only the crossover jumper will be used to connect the normal ports of the two switches, extending the number of network ports. It is important to note that when connecting to a switch using a normal port, you must use a crossover line instead of a straight line. Use the crossover line to cascade the switch through the normal port.

Cascade of Switch Fibre ports

Because the price of the switch fibre port is still very expensive, the fiber is used primarily for connecting between the core switch and the backbone switch, or for cascading between the backbone switches. It should be noted that the switch fibre ports are not stacked and can only be used for cascading.

Cross-connect of fiber jumper

All switch fibre ports are 2, each is a single charge. Of course, the fiber jumper must also be 2, otherwise the port will not be able to communicate. When the core switch is cascaded through the core switch fibre port, the transceiver must be swapped at both ends of the fiber jumper, and when the end is received, the other end is sent.

Similarly, when the end of the "hair", the other end of the "receive". Thankfully, the ciscogbic fiber module is labeled with a transceiver, the left arrow indicates "collect", and the right arrow indicates "hair". If both ends of the fibre jumper are connected to "collect" or "send", the LED on the port is not lit, indicating that the connection failed. The LED is turned green only if the switch fibre port is connected successfully.

Cascade of Switch Fibre ports

Similarly, when a backbone switch is connected to a core switch, the transceiver port of the fiber must also be crossed. The connection between the core switch and the backbone switch.

Fibre jumper and switch fibre port type

Fiber jumpers are divided into single mode fiber and multimode fiber. Switch fibre ports, jumpers must be consistent with the type of fiber used in the integrated wiring, that is, if the multimode fiber used in the cabling is integrated, then the fiber interface of the switch must perform the 1000BASE-SX standard, and the multimode fiber jumper must also be used; If a single mode fiber is used for integrated wiring, then, The fibre interface of the switch must perform the 1000BASE-LX/LH standard, and the single mode fiber jumper must also be used.

It should be noted that there are two types of multimode fiber, namely 62.5/125μm and 50/125μm. Although the switch fibre port is identical and both perform the 1000BASE-SX standard, the core diameter of the fiber jumper must be identical to the core diameter of the optical cable.

Otherwise, it will cause connectivity failures. In addition, the types of fibre ports for interconnected switches must be identical, either multimode switch fibre ports or single mode switch fibre ports. One end is a multimode switch fibre port, and the other end is a single-mode switch fibre port and will not be able to be connected together.

Transfer rate and Duplex mode

Unlike 1000base-t, 1000BASE-SX, 1000BASE-LX/LH, and 1000BASE-ZX cannot support adaptive, and ports with different speed and duplex modes will not be able to connect and communicate.

Therefore, a fibre port that requires a connection must have exactly the same transfer rate and duplex mode to connect the 1000Mbps switch fibre port to the 100Mbps fibre port. It is also not important to connect fibre ports in Full-duplex mode with the core switch fibre ports in Half-duplex mode, otherwise, connectivity failures will occur.