Discussing the distance of shared Ethernet, you can't ignore the concept of collision domain (CollisionDomain).
Media access for shared Ethernet or half-duplex Ethernet is determined by Carrier Sense Multiple Access/Collision Detection (CSMA/CD). In the half-duplex communication mode, sending and receiving cannot be performed at the same time, otherwise the data will collide. Before the site is sent, the first thing to look at is whether there is a free channel. When sending, the site will listen for a while, ensuring that no other sites are transmitting synchronously during this time, and finally the station sends successfully. Conversely, in the event of a collision, the source station sends a blocking signal to enhance the collision. After the contention of the competing site is delayed (the delay time is determined by the algorithm, it is random) retry. Under this mechanism, all sites and all hubs must be in the same collision domain.
For industrial Ethernet, 10Mbps and 100Mbps are the most commonly used. In an Ethernet network with 10 Mbps and all twisted pairs, there are two concepts related to distance, namely, segment and networkDiameter. The former refers to the distance between two devices (hubs, switches, or hosts), and the latter refers to the distance between the two most remote devices in the network. Regardless of the 10Mbps or 100Mbps network, the network segment's maximum distance cannot exceed 100 meters. Considering network extensions, the most useful rule is the 5-4-3 rule (for 10Mbps repeaters only). The content of the rule is as follows: A network has up to five network segments, four repeaters, and no more than three hybrid network segments. The hybrid network segment refers to the coaxial bus segment (deprecated). Since the maximum distance of the twisted pair network segment is 100 meters, the maximum network (network range) is 500 meters.
The farthest distance of the fiber network segment can reach 2 kilometers, but the IEEE802.3 standard stipulates that the fiber can be used, the maximum number of cascades cannot exceed three, and the end of the network needs to use twisted pair, and the middle two are fiber network segments and ensure Each segment does not exceed 1 km. In this way, the length of the entire fiber segment is limited to 2 kilometers.
The 5-4-3 rule is not applicable to 100Mbps. A 100Mbps switch is recommended.
Ningbo Autrends International Trade Co.,Ltd. , https://www.supermosvape.com