Table Of Contents

Monitoring FDDI Networks

Overview of Monitoring FDDI Networks

Building the Ring Map

Using Ring Monitor to Monitor FDDI Networks

Viewing the Ring Station List

Understanding the Ring Station List Upper List Box Display

Understanding the Ring Station List Lower List Box Display

Selecting Active Stations Only

Sorting List Box Information

Monitoring FDDI Networks

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The TrafficDirector application includes tools you can use to monitor FDDI networks.

The following sections describe the monitoring tools and how to use them:

•Overview of Monitoring FDDI Networks

•Using Ring Monitor to Monitor FDDI Networks

Overview of Monitoring FDDI Networks

Station Management (SMT) is the layer of the FDDI protocol responsible for monitoring network operation, detecting errors, and isolating faults. SMT initializes nodes, inserts nodes to the ring, and removes nodes from the ring.

Each FDDI node participates in ring management by exchanging SMT information (using SMT frames) with other nodes on the ring. There are different types of SMT frames, each used for a specific purpose. For example, SMT Status Report Frames are sent wherever there is a change in the ring configuration. Similarly, SMT Neighbor Information Frames (NIFs) are used by FDDI nodes to determine or announce their neighbors. These SMT NIF frames contain the address of the sender, the address of its nearest upstream neighbor, and additional information about the node itself.

By capturing and analyzing these frames, you can use Ring Monitor to build a map of the ring. You can use Ring Monitor to configure, display, and print FDDI statistics.

The following section describes how to build the ring map:

•Building the Ring Map

Building the Ring Map

Ring Monitor builds a ring map by collecting SMT Neighbor Information Frames. These SMT frames are exchanged periodically, in intervals between two and 30 seconds. When you start Ring Monitor, the FDDI NSP starts collecting the SMT-NIFs and building the FDDI ring map.

However, the ring map is complete only when the SwitchProbe device has collected SMT-NIFs from all nodes on the ring. Until that happens, a partial ring map displays and the Ring Map Status in Ring Monitor is displayed as Incomplete.

When the ring map is complete (typically, 10 to 60 seconds later), the Ring Map Status is displayed as Complete. The ring map is rebuilt whenever there is a change in the ring configuration.

Although the time it takes to build the ring map is typically less than 60 seconds, under certain conditions, the ring map may take longer to build, or may never build at all. If the ring is overloaded, the nodes take longer (several minutes) to exchange SMT-NIFs. Therefore, the time to build the ring map also increases.

If a node on the ring has stopped, or there is a node that does not exchange SMT-NIFs, the ring map will never be completed. This happens if the node

•Has hung.

•Is too busy to participate in the SMT-Neighbor Protocol.

•Does not conform to the SMT-NIF protocol.

Using Ring Monitor to Monitor FDDI Networks

The following sections contain information about the procedures you use to monitor your FDDI network with Ring Monitor.

The following section contains additional information about using Ring Monitor:

•Viewing the Ring Station List

Viewing the Ring Station List

To start Ring Monitor and display the Ring Station List for the FDDI agent you select, follow these steps:

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Step 1 Start Ring Monitor.

The Ring Monitor main window (the Ring Station List) is displayed for the selected agent ().

Figure 14-1 Ring Station List Window (FDDI Network)

The following sections provide more information about the Ring Station List Window:

•Understanding the Ring Station List Upper List Box Display

•Understanding the Ring Station List Lower List Box Display

•Selecting Active Stations Only

•Sorting List Box Information

Understanding the Ring Station List Upper List Box Display

The Ring Station List window is divided into an upper list box and a lower list box. The upper list box shows information about each of the nodes on the ring, and contains the information described in .

Table 14-1 Ring Station List Window—Upper List Box 

This Field...	Displays This Information
Ring Order	The order of this station in the ring.
Station	The name of the station.
Address	The address of the station.
Last Enter Time	The last time the station entered the ring.
Last Exit Time	The last time the station exited the ring.
RIns	Ring insertions; the number of times a station has been inserted into the ring.
Status	Whether a station is active (currently in the ring) or inactive (not currently in the ring).
Topology State	Whether a node is correctly connected on the ring.

Understanding the Ring Station List Lower List Box Display

The lower list box shows information about the specific node highlighted in the upper list box, and contains the information described in .

Table 14-2 Ring Station List Window—Lower List Box 

This Field...	Displays This Information
Station Address	The name and address of the highlighted station.
Nearest Upstream Neighbor Address	The address of the nearest active upstream neighbor (NAUN) of the highlighted station.
Node Class	Whether the FDDI node is a station or a concentrator. The primary purpose of a station is to transmit and receive information. Concentrators are like hubs, providing facilities to connect additional nodes. Some types of nodes can have zero, one, or two MAC addresses. For example, a Dual Attachment node with two MAC addresses can simultaneously receive and transmit frames on both logical rings. This cannot be done with a Dual Attachment node that has only one MAC. Node Class indicates the node type: •Single Attachment STATION (SAS). •Single MAC—Dual Attachment STATION (SM-DAS). •Dual MAC—Dual Attachment STATION (DM- DAS). •MACless—Single Attachment CONCENTRATOR (SAC). •Single MAC—Single Attachment CONCENTRATOR (SAC). •Single MAC—Dual Attachment CONCENTRATOR (DAC). •Dual MAC—Dual Attachment CONCENTRATOR (DAC).
Topology State	The state of the node to indicate whether it is correctly connected on the ring. The states are: •Normal—The node is correctly connected. •Twisted Ring A-A—In case of a Dual Attachment Node, the A-port should be connected to the B-port of its Upstream Neighbor and the B-port should be connected to the A-port of its Downstream neighbor (except if Dual Homing is used). Connecting the A-port of Dual Attachment Node to the A-port of another Dual Attachment Node results in a topology that is referred to as a twisted ring. •Twisted Ring B-B—This is similar to the Twisted Ring A-A topology explained above, except that it's caused by connecting the B-port of a Dual Attachment Node to a B-port of another Dual Attachment Node. •Wrap—FDDI defines a redundant topology network. If a fault occurs on the trunk ring, then the Dual Attachment Nodes on either side of the faulty link wrap around to bypass the faulty link These nodes are then said to be in a wrapped state. •Peer Wrap—Occurs when a fault in a node causes the node to wrap within itself.

The information in indicates how the node is connected to the FDDI ring.

Table 14-3 Connections to an FDDI Ring 

Connection Mode	Description
Rooted Station/ Station Not Rooted	Displayed if the node is a Station. A station is rooted if it does not have an active A, B, or S port in tree mode. This indicates whether the station is directly connected on the trunk ring (rooted), or if it is connected through a concentrator as part of a tree topology (unrooted).
Attached Concentrator/ Unattached Concentrator	Displayed if the node is a concentrator.
Unattached Concentrator	Displayed if the node is a concentrator. A concentrator is unattached if it does not have an active A, B, or S Port. In an FDDI dual-ring topology or a dual-ring with trees topology, all concentrators are normally attached. In an FDDI tree topology, any number of concentrators are arranged in a hierarchy, with a number of stations attached to each concentrator. In this topology one concentrator is the root of the tree. This concentrator is unattached. All other concentrators are attached under normal conditions.
Synchronous Service	FDDI allows for two different types of traffic: •Synchronous—Consists of delay-sensitive traffic such as voice packets, which need to be transmitted within a certain time interval. •Asynchronous—Consists of data traffic produced by various computer communication applications such as file transfer and electronic mail, among others. These data packets can sustain some reasonable delay. If the node supports Synchronous traffic, the following message is displayed: Synchronous Service: Supported If it does not support Synchronous traffic, the following message is displayed: Synchronous Service: Not Supported
Duplicate MAC Address Test	On an operational FDDI ring, each node periodically checks to see if there is any other node with the same MAC address as its own. If a duplicate MAC address condition does not exist, the following message is displayed: Duplicate MAC Address test: Passed If not, either of the following messages is displayed: Duplicate MAC Address test: Failed (My duplicate exists). Duplicate MAC Address test: Failed (My Upstream is duplicate).

Selecting Active Stations Only

To view data on active stations, follow these steps:

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Step 1 Select View from the menu bar.

Step 2 Click Active Stations Only.

Sorting List Box Information

To change the way information is sorted in the window list box, select Sort from the menu bar, then select one of the variables listed in .

Table 14-4 Sorting List Box Information 

Select This Variable...	To Sort According To
Ring Order	The position of the station in the ring. Note   This is the default sort order.
MAC Order	MAC addresses, sorted in descending order.
Enter Time	The last time the station entered the ring, sorted in descending order.
Exit Time	The last time the station exited the ring, sorted in descending order.