The FDDI Ring Manager for the HP Network Advisor protocol analyzer

Hewlett-Packard Journal, Oct, 1994 by Sunil Bhat, Robert H. Kroboth, Anne L. Driesbach

FDDI (Fiber Distributed Data Interface) networks offer high-speed data transfer and fault-tolerant dual-ring topology, but can add a layer of complexity to troubleshooting network problems. The dual ring can become twisted or wrapped, a serious problem that may not be immediately apparent. Interoperability issues can cause ring abnormalities between products from different vendors, but tracing these glitches to their source by looking at decodes can be intensely time-consuming. And, although the FDDI station management protocol defines a management information base (MIB) full of

interesting information, it may not be convenient to access and make sense of that information. The FDDI Ring Manager application for the HP 4980 Series Network Advisor protocol analyzers(1) addresses these and other FDDI network management issues in one integrated network management application. Fig. 1 shows the FDDI Ring Manager user interface. The current state of the dual ring and general network performance are reported along with other interesting network information in the top area of the window. The middle area of the window is a graphical map of the FDDI network. The nodes on the map can be opened to examine station management MIB information. The FDDI Commentator, which is automatically started when the FDDI Ring Manager application is started, reports trends, changes, and events of interest.

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The design of the FDDI Ring Manager is based on customer input. Early in the investigation stages of the FDDI Ring Manager, we decided to use five customer sponsors as development partners. After the first several interations with the five sponsors, customer requirements could be summarized as:

* Make it easy to see what's happening on the network

* Make it easy to see where network problems are

* Automate tedious tasks

* Provide a tool that does not require the user to be an expert on the Network Advisor and an expert on FDDI protocols.

As a result of ongoing customer consultations, we answered these requirements with the following FDDI Ring Manager features:

* A ring status section to give a high-level overview of the ring state

* Physical and logical ring maps to show graphical network topology

* Dynamic error indication using colors to isolate problem nodes

* Automated polling of each station management MIB for proactive indications of marginal conditions

* Station information windows to give an orderly presentation of station management MIB information

* The FDDI Commentator to provide a history of events, trends, and changes on the FDDI ring

* Ease of building a node list provided by a link from the FDDI topology maps to the node list.

The key contribution of the FDDI Ring Manager is to take the knowledge burden from the user and put it where it belongs, on the network management tool. Instead of requiring the user to sift through station management decodes looking for fields that may relate to the status of the ring, the FDDI Ring Manager pulls that information from station management frames and presents it in a logically ordered display. Rather than expect the network manager or operator to look at neighbor information frames and figure out which stations are upstream and downstream of a particular station, the FDDI Ring Manager presents that information in a graphical map and in a textual report. Why require the user to keep track of changes in link error rates for particular stations or trends of claiming(2) by one or more stations? This information can be collected and synthesized into meaningful events that are logged in the FDDI Commentator. Fig. 2 shows the FDDI Commentator window.

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FDDI Ring Manager Overview

The FDDI Ring Manager window is divided into three panes: the ring status section, the ring maps or topology section, and the status bar.

Ring Status. The top section of the FDDI Ring Manager window is the ring status section. It provides high-level network health information. Some of the indicatiors in this section are:

* Ring State: Shows whether the ring is in a normal, twisted, or wrapped state.

* Observed Token Rotation Time (TRT): This is the actual time interval between successive tokens.

* Active MACs: This is a list of currently active media access control units (MACs) for each FDDI station type.

* Network Traffic: Shows the current level of network traffic displayed as a percentage of total bandwidth, and in frames per second and kilobytes per second.

* Ring Op Statistics: This is the number and peak rate of ring initializations in any five-second interval since the start of the FDDI Ring Manager measurement.

* Commentator Events: This field shows how many events of each level of severity have occurred and how many were logged to the Commentator.

Ring Maps. The next section of the FDDI Ring Manager window is the ring maps. The direct-manipulation graphical network map shows the token path through the ring in the logical ring map or the hierarchy of the physical connections in the physical ring map. Nodes on the graphical maps turn red or yellow to give dynamic error indication of problems. You can open or "drill down" into the problem nodes or any selected node on the map to see the current configuration and station management MIB values.