8.1.2 Ring Administration

The token-passing ring protocol provides relatively greater control and management at the medium access control (MAC) level than that provided by the CSMA/CD protocol. All ring administration functions are implemented in the token-ring adapters and the functions are carried out at the MAC level.

8.1.2.1 Active Monitor

In each operational ring, one station assumes the role of the active monitor. The process of active monitor selection is described in 8.1.2.2, ªToken-Claiming Processº on page 131.

The following are the responsibilities of the active monitor:

∙Maintain the master clock

The active monitor maintains the ring′s master clock. All the other clocks on the ring are synchronized with the active monitor′s clock.

∙Ensure proper ring delay

To ensure that a token is completely transmitted before returning to the originating ring station, the active monitor introduces a 24-bit delay (the length of token) into the ring.

∙Initiating neighbor notification

Every seven seconds, the active monitor broadcasts an Active Monitor Present (AMP) MAC frame to all the stations on the ring. The first station

that receives this frame, copies it and sets the address-recognized (A) and frame-copied (C) bit to B′1′. This station, then saves the source address

field from the copied frame as its Nearest Active Upstream Neighbor (NAUN). After a period of time called notification-response time, this station transmits a Standby Monitor Present (SMP) MAC frame to all the stations on the ring.

The next downstream station ignores the Active Monitor Present MAC frame (because the A and C bit are set to B′1′), but it copies the Standby Monitor Present MAC frame issued by its NAUN. It then sets the A and C bits to B′1′

and also copies its NAUN from the source address of this MAC frame. This station will, in turn, transmit its own Standby Monitor Present MAC frame.

In this way, neighbor notification proceeds around the ring with all the stations transmitting their own Standby Monitor Present MAC frame until the

active monitor copies the last Standby Monitor Present MAC frame, in which the A and C bit are set to B′0′. At this point, the neighbor notification is

considered complete.

As can be seen, the neighbor notification (which is also referred to as ring poll) enables each ring station to learn its NAUN address and to provide its address to its downstream neighbor. This process is used by the TRMM in the 8250 and the token-ring media modules in the 8260 to perform the address-to-port mapping which enables them to determine what is the address(s) of station(s) attached to each port. The details of address-to-port mapping are described in 8.10, ªAddress-to-Port Mapping for Module Switching Modulesº on page 160 and 8.11, ªAddress-to-Port Mapping for Per-Port Switching Modulesº on page 164.

∙Initiate ring purge process

Occasionally, the active monitor may need to initiate a ring purge process to reset the ring stations, all appropriate timers and release a new token. The

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8260 specifications

The IBM 8260 is a significant entry in the realm of enterprise servers, recognized for its performance, scalability, and robust features designed to cater to demanding business environments. It primarily serves as a high-capacity server for large organizations, capable of handling extensive workloads and complex applications without compromising speed or efficiency.

One of the standout features of the IBM 8260 is its powerful processing capabilities. It typically comes equipped with multiple processor units based on the IBM POWER architecture, which is renowned for its high-performance computing. This architecture allows the server to execute numerous simultaneous tasks, making it ideal for environments that require multitasking and high throughput.

Memory capacity is another key characteristic of the IBM 8260. Depending on the specific configuration, it can support substantial amounts of RAM, ensuring that applications can run effectively without the bottlenecks often associated with data-intensive tasks. This is crucial for enterprises that rely on real-time data analytics, large database management, and resource-heavy applications.

In terms of storage, the IBM 8260 offers flexible options. It supports a variety of storage solutions, including solid-state drives (SSDs) and traditional hard drives, catering to different performance and capacity needs. This scalability in storage helps organizations manage their data effectively while ensuring quick access and retrieval times.

Connectivity is also a prominent feature of the IBM 8260. The server includes advanced networking capabilities, supporting various protocols and technologies that facilitate fast data transfer and communication between devices. This enhances overall network performance, essential for businesses that depend on cloud computing and distributed computing environments.

Additionally, the IBM 8260 is designed with a focus on reliability and availability. It incorporates redundant components, such as power supplies and cooling systems, minimizing the risk of downtime. This is critically important for enterprises that require continuous availability of services.

The server’s management features are also noteworthy. IBM provides a suite of management tools that allow IT administrators to monitor performance, configure hardware settings, and troubleshoot issues seamlessly. This ease of management is bolstered by automation capabilities, enabling organizations to enhance operational efficiency.

In conclusion, the IBM 8260 stands out in the competitive server landscape due to its high processing power, extensive memory and storage options, advanced connectivity, reliability features, and robust management tools. Such attributes make it a viable choice for organizations seeking to enhance their IT infrastructure and streamline their operations effectively.
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