8.9 Beacon Recovery

8.9.1 Introduction

When a station detects a failure of token-claiming following a hard error, it transmits Beacon MAC frames with an all-station address to its ring, pacing them at a specified time interval known as ″T(transmit_pacing)″. This process will continue until the input signal is restored, or until this station removes itself from the ring for self-testing, as described below.

The issued Beacon MAC frames contain the issuing station′s source address, its NAUN (Nearest Active Upstream Neighbor) address as well as the type of the error detected. By inspecting these Beacon frames, the beacon domain (the two stations between which lies the cause of beacon) can be determined.

When the beaconing station′s NAUN has copied eight of these Beacon MAC frames, the NAUN station removes itself from the ring and tests itself and its lobe (using Lobe Media Test and Duplicate Address Test MAC frames). If the test fails, the NAUN remains out of the ring allowing the normal operation of the ring to resume. If the test is successful, the NAUN re-enters the ring.

If the ring does not recover after a specified period of time known as

″T(beacon-transmit)″the beaconing station assumes its NAUN has completed its self-test and did not find any fault and has re-entered the ring. Therefore, the beaconing station removes itself from the ring and tests itself and its lobe using the same procedure as its NAUN. If the test fails, the beaconing station remains out of the ring, resulting in the signal being restored to the ring and the normal operation of the ring being resumed. If the test is successful, the beaconing station re-enters the ring and continues to send the Beacon MAC frames.

If the ring does not recover after both the beaconing stations and its NAUN have been tested, the error cannot be repaired by the attaching stations, and some other function must intervene to resolve the problem. In the 8250, this function is performed by the Token-Ring Management Module (TRMM), whereas in the 8260, the beacon recovery is performed by the media modules.

8.9.2 Beacon Recovery in the 8250

The TRMM can detect beaconing conditions on the ring to which it is attached through its token-ring MAC chip. The TRMM will use the following resources to attempt to find the cause of the beaconing and disable a port or trunk or isolate

amodule:

∙The token-ring map indicating MAC addresses and their corresponding port. This map is built and maintained by the TRMM.

By listening to the neighbor notification process (one complete sequence of Active/Standby Monitor Present MAC frames), TRMM can determine the MAC addresses of all the stations that are attached to the ring. Then, by using its own MAC address and also the knowledge that it has of all the ports which are active (a phantom signal detected) in the hub managed by this TRMM, it determines which of these MAC addresses are connected to the hub which is managed by this TRMM and which MAC addresses are external (connected to other hubs or are on a backplane ring other than the one to which this TRMM is attached). The other hubs, can be 8228, 8230, 8250, 8260 and/or OEM hubs.

Chapter 8. 8260 Token-Ring Support 151

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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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