Configuring an FDDI Interface and Displaying Status Information

Use the GS2000 FDDI Status and Configuration window to display the status and current configuration of the FDDI interface.You can also configure the FDDI interface.

Note:  The FDDI interface on the GS2000 line card is automatically configured  when the line card is installed. However, you may need to alter the default settings to maximize network performance, or to accommodate requirements unique to your network environment.

Caution:  It is recommended that the only configuration tasks you perform on an FDDI interface are enabling or disabling an interface, setting the interface for full- or half-duplex mode, setting the station type, and resetting parameters to defaults (these last two tasks are performed via the CLI). It is recommended that you alter the remaining settings only if you fully understand the effect the change will have on the entire network.

Enabling an FDDI Interface

The FDDI interface on the GS2000 line card is automatically enabled when the line card is installed. If you have previously disabled an interface, and need to enable it, perform the following procedure.

Procedure:

Step Action
1 Select Enabled from the drop-down box next to the Interface field in the Configuration section.
2 Click Apply.

Note:  You do not need to restart the line card for the new setting to take effect. The setting is effective immediately.

Disabling an FDDI Interface

By default, the FDDI interface on the line card are enabled. You might need to disable the interface, for example, if you want to logically disconnect a portion of your network while making changes to the network segment's physical environment. 

Procedure:

Step Action
1 Select Disabled from the drop-down box next to the Interface field in the Configuration section.
2 Click Apply.

Note:  You do not need to restart the line card for the new setting to take effect. The setting is effective immediately.

Setting the Link Error Rate Alarm

To set the link error alarm, refer to the FDDI Interface Configuration section of the window and perform the following procedure.

Procedure:

Step Action
1 In the input box next to the PHY A/M or PHY B/S field under the LER Alarm field, enter a whole number from 4 through 12, where the number is a negative exponential value of base 10. For example, entering a 4 sets the value at 10-4 (0.0001 bits per second), entering a 5 sets the value at 10-5 (0.00001 bits per second), and so on.

The default value is 8.

2 Click Apply.

Automatically Disconnecting Nodes Causing Excessive Link Errors

To configure the GS2000 line card to automatically disconnect nodes that are causing excessive link errors, refer to the FDDI Interface Configuration section of the window and perform the following procedure. For more information, see Cutoff Value for Link Errors.

Procedure:

Step Action
1 In the input box next to the PHY A/M or PHY B/S field under the LER Cutoff field, enter a whole number from 4 through 12, where the number is a negative exponential value of base 10. For example, entering a 4 sets the value at 10-4 (0.0001 bits per second), entering a 5 sets the value at 10-5 (0.00001 bits per second), and so on.

The default value is 8.

2 Click Apply.

Enabling or Disabling the Ring Purger

To enable or disable the ring purger, refer to the FDDI Interface Configuration section of the window and perform the following procedure.

Procedure:

Step Action
1 Select Enable or Disabled from the drop-down box next to the Ring Purger field.
2 Click Apply.

Setting Token Passing and Frame Timing Parameters

To set the FDDI token passing and frame timing parameters, refer to the FDDI Interface Configuration section of the window and perform the following procedure.

Procedure:

Step Action
1 In the input box next to the T_Req field, enter the amount of time in milliseconds that the station waits to negotiate for token possession.

The value entered must be greater than the Minimum Token Rotation Time (6 milliseconds) and less than the T_Max  (Maximum Token Rotation Time) value. The default is 8 milliseconds.

Note: The software rounds the specified value to the nearest multiple of 20.48 microseconds. For example, the default value of 8 milliseconds is interpreted by the software as 7.9872 milliseconds.

2 In the input box next to the T_Max field, enter the maximum amount of time in milliseconds that the station waits to receive a token.

The number can be a number from 8 through 1331 milliseconds. The default is 167 milliseconds.

Note: The software rounds the specified value to the nearest multiple of 5.24288 milliseconds. For example, the default value of 167 milliseconds is interpreted by the software as 167.77216 milliseconds.

3 In the input box next to the TVX field, enter the maximum number of milliseconds the interface waits for a data frame. The number can be a number from 1 millisecond through 5 milliseconds. The default is 2.5 milliseconds.

Note: The software rounds the specified value to the nearest multiple of 20.48 microseconds. For example, the default value of 2.5 milliseconds is interpreted by the software as 2.51904 milliseconds.

4 Click Apply.

Configuring Duplex Mode

You can set the FDDI interface to function in either full-duplex or half-duplex mode. If you set the interface for full-duplex mode, the link will function as a full-duplex circuit only if the device with which auto-negotiation occurs is also enabled for full-duplex mode; otherwise, half-duplex mode is used.

To set the FDDI interface for either full-duplex or half-duplex mode, refer to the FDDI Interface Configuration section of the window and perform the following procedure.

Procedure:

Step Action
1 Select Half or Full duplex from the drop-down box next to the Duplex Mode field.
2 Click Apply.

Note:  You do not need to restart the line card for the new setting to take effect. The setting is effective immediately.

Enabling or Disabling SMT Notification

FDDI stations use Status Report Frames (SRFs) to notify the SMT management station about certain events or conditions. The events and conditions can include, for example, ring wrap, exceeding thresholds such as link error alarm and cutoff values, and the detection of an illegal port type configuration.

To enable or disable sending of Status Report Frames to the SMT management station, refer to the FDDI Interface Configuration section of the window and perform the following procedure.

Procedure:

Step Action
1 Select Enable or Disabled from the drop-down box next to the Status Report field.
2 Click Apply.

Performing Other Configuration Tasks

Use the CLI to perform the following configuration tasks:

Field Descriptions

Station Status
MAC Address MAC address of the interface.
Upstream Neighbor FDDI MAC address that identifies the most recently known upstream neighbor. In FDDI terminology, this address is called a UNA.
Downstream Neighbor FDDI MAC address that identifies the most recently known downstream neighbor. In FDDI terminology, this address is called a DNA.
Policy Shows the PHY port type connection combinations not allowed (rejected) on the interface's PHY ports. For example, reject A-A B-B M-M indicates that a link between PHY A port on one station and PHY A port on a second station is not allowed. PHY B port-to-PHY B port and PHY M port-to-PHY M port are also not allowed.
FDX State Indicates whether full-duplex mode is active or idle on the FDDI interface. Possible states include: fdxIdle, fdx Operation, fdx Request, and fdx Confirm.
  • A value of fdx Operation indicates the interface is set to full-duplex mode and a full-duplex circuit was established following auto-negotiation.
  • A value of fdx Idle indicates the interface is either set to half-duplex mode, or set to full-duplex mode but a half-duplex circuit was established following auto-negotiation.
  • The fdx Request and fdx Confirm states are transitional states.
Optical Bypass True indicates an optical bypass relay (OBR) is present. False indicates an OBR is not present.
Purger State Indicates the state of the Ring Purger. Possible states include: Purger Off, Candidate, Nonpurger, and Purger.
Station Type Displays the station type to which the interface is set. Possible values include DAS, SAC, or SAS.
RMT State Identifies the Ring Management (RMT) software monitoring the state of the ring. Possible values include: Isolated, Non-Op, Ring-Op, Non-Op-Dup, Ring-Op-Dup, Directed, and Trace.
ECM State Displays the FDDI Entity Connection Management (ECM) state. ECM controls and manages the optical bypass. Possible states include: In, Out, Trace, Leave, Path-Test, Insert, Deinsert, and Check.
CFM State Displays the FDDI Configuration Management State (CFM) state. Possible states include: Isolated, Local-a, Local-b, Local-ab, Local-s, Wrap-a, Wrap-b, Wrap-ab, Wrap-s, C-wrap-a, C-wrap-b, C-wrap-s, and Thru.
Timers
T_Neg Displays the token rotation time.
T_Req Displays the Requested Token Rotation Time (t-req).
TVX Displays the Valid Transmission Timer setting. This value is the maximum amount of time the interface waits to receive a valid data frame.
T_Max Displays the Maximum Token Rotation Time (tmax-lower-bound).
T_Notify Displays how often the interface generates Neighbor Information Frames (NIF) to neighbor nodes. This parameter is not user-configurable.
Ring Latency Amount of time it takes for data to make one rotation around the ring.
Counters
Frame Count Displays the total number of frames passed on the ring since the last restart.

Note: Disable the ring purger on all devices on the ring to get the most accurate ring utilization frame count. If the ring purger is on, void frames transmitted by the MAC are also counted, artificially increasing the frame count.

Beacon Rcv Displays the total number of times the interface received its own beacon frames and those of other stations since the last restart.
Trace Rcv Displays the number of trace frames received.
Frame Error Displays the total number of Cyclic Redundancy Check (CRC) errors that occur on the ring since the last restart.
Beacon Xmt Displays the number of times the interface entered the Beacon Transmit state since the last restart.
Trace Xmt Displays the number of trace frames transmitted.
Frames Lost Displays the total number of frames lost on the ring since the last restart.
Ring Inits Indicates the number of times the FDDI ring has gone through the Claim process and generated a token. (This is a normal occurrence whenever a station is added or removed from the FDDI network.)
Bad CRC Sent Displays the total number of bad CRCs transmited over the interface.
PHY Status (Type A and Type B)
Connect State Indicates the state of the PHY port.   Possible states include Disabled, Connecting, Stand By, and Active.
LEM Rejects Displays the number of times the Link Error Monitor detects a link was rejected.
LCT Rejects Displays the number of times the link confidence test failed since the last restart.
LER Estimate Displays the estimated bit error rate based on link monitoring.
LEM Errors Displays the total number of link error events that occurred since the last restart.
FDDI Interface Configuration
Interface Specifies whether the FDDI interface is enabled or disabled.
LER Cutoff

PHY A/M and B/S

Specifies the link error rate cutoff values for the A/M and B/S PHY ports.
LER Alarm

PHY A/M and B/S

Specifies the link error rate alarm values for the A/M and B/S PHY ports.
Ring Purger Specifies whether the ring purger is enabled or disabled.
T_Req Specifies the requested token rotation time to negotiate for token possesion.
T_Max Specifies the length of time a station waits to receive the token since the last time it had possession.
Full Duplex Specifies whether the interface is set to full- or half-duplex mode.
TVX Specifies the maximum of time the interface waits to receive a valid data frame.
Status Report Specifies whether SMT notification is enabled or disabled.