Automatic Beacon Recovery Process

wrong ring speed. If a ring speed mismatch is detected, the STH disables the port to keep the misconﬁgured station isolated from the ring and provides a simple visible LED signal (blinking red at the port’s LED) to indicate to the user that Speed Fault Protection has disabled the port. The port remains disabled until the ring speed mismatch condition is removed or resolved.

Active Circuitry

On each TCU port, STH hubs provide active circuitry which ﬁlters, equalizes, and ampliﬁes all received signals before transmitting them to the next point on the ring. The result is enhanced signal integrity and extended maximum station lobe cable distances.

Daughter Board Upgrade Kit

Both the STH-22 and the STH-42 can be upgraded to 24 ports using the following daughter board upgrade kits:

•TR-UTP-UGKT for STH-22.

•TR-STP-UGKT for STH-42.

1.2.3Automatic Beacon Recovery Process

To guard against interruptions in network operations due to beaconing conditions, the STH supports Cabletron Systems’ advanced Automatic Beacon Recovery Process which automatically partitions problematic lobes from the ring, allowing the rest of the ring to continue operating. (ABRP engages even before the IEEE standard beacon recovery process begins and is able to treat conditions beyond the scope of the IEEE process.) It is the stack’s intelligent hub that actually executes the ABRP algorithm. The intelligent hub also checks partitioned lobes periodically and re-enables them automatically once they have recovered.

1.2.4Support for Passive MAU Workgroups

Whereas a station signals a TCU to open its interface by sending a phantom current down its lobe cable, a passive Multi-Station Access Unit can not provide phantom current. A TCU Ring Out port is therefore conﬁgured to ignore the absence of phantom current in the connecting cable and to look instead for the presence of data bits to determine link status.

Page 1-4

42, 24, STHI-44, STH-22 specifications

Cabletron Systems was a pioneer in networking technology, and its STH series, particularly the STH-22 and STHI-44, 24, and 42 models, stand out in the history of networking equipment. These devices were designed for high-performance network management and offered a multitude of features that helped organizations manage their networking resources efficiently.

The STH-22 was a compact and efficient network switch, primarily developed to serve small to medium-sized businesses. One of its main features was its ability to support multiple user connections while offering low latency and high throughput. The STH-22 utilized advanced packet-switching technology to ensure data could move rapidly across the network, enhancing overall communication and productivity.

On the other hand, the STHI-44 model addressed the needs of larger enterprises. It featured advanced routing protocols and could handle a greater number of simultaneous connections, making it ideal for environments with high data traffic. The STHI-44 also incorporated redundancy features to minimize downtime, a vital requirement for businesses that relied heavily on continuous network availability.

The STH-24 and STH-42 models focused on versatility and scalability, catering to a broad range of networking needs. Both models provided extensive support for various networking protocols and featured robust hardware for enhanced durability. The STH-24 was designed for offices requiring mid-range capabilities, while the STH-42 targeted enterprises with more demanding networking requirements.

All STH series devices were built with ease of management in mind. They included user-friendly interfaces that allowed IT personnel to monitor traffic, configure network settings, and troubleshoot issues in real-time. Additionally, the devices supported SNMP (Simple Network Management Protocol) for seamless integration into existing network management systems.

Another defining characteristic of the Cabletron STH series was its commitment to security. These devices came equipped with features that permitted administrators to set access controls and monitor network activity, thereby safeguarding against unauthorized access and potential threats.

In summary, Cabletron Systems' STH-22, STHI-44, STH-24, and STH-42 models represent a significant advancement in networking technology. With their diverse features, high-performance capabilities, and user-centric design, they have served a critical role in optimizing network resources, ensuring businesses were equipped to handle increasing connectivity demands.