Configuring an ATM LAN Emulation Client (LEC) and Displaying Status Information

Use the ATM LEC Status and Configuration window to:

  • Display status information about the ATM logical interface

  • Display transmission/reception statistics

  • Display information about the virtual circuits used by the ATM logical interface

  • Display ATM LAN emulation client (LEC) configuration information

  • Configure the ATM logical interface

The ATM port (physical interface) on the GS2000 line card supports as many as 16 logical ATM interfaces.  Each logical interface can be configured as either an ATM LAN emulation client (LEC) or a bridge tunnel.

For additional information, refer to ATM Logical Interfaces Established at Startup.

Configuring an ATM LAN Emulation Client (LEC)

To configure the ATM logical interface as a LAN emulation client (LEC), refer to the ATM LEC Configuration section of the window and perform the following procedure.

Procedure:

Step Action
1 By default, the interface PHY type is set to Sonet.  To view the Sonet configuration, click Sonet.
2 To enable or disable this ATM logical interface, select enable or disable from the drop-down box next to the Interface field.
3 Select the configuration mode for identifying the LES address, either manual or automatic.
4 For manual mode, enter the LES server address.  This is the address of the LAN Emulation Server (LES) responsible for the ELAN to which the LEC connects. The address has 3 parts:
  • Address Prefix
  • MAC Address
  • ATM Address Selector

Note:   The LES address must be entered using the hexadecimal value.

5 Select the maximum frame size from the drop-down box. You can set the maximum frame size to either 1516 octets or 4544 octets.  The default GS2000 LEC maximum frame size is 1516 octets.

Note:   ELAN services require that the maximum frame size is the same for all LECs belonging to a specific ELAN.  All LECs that are members of an ELAN participate in a negotiation process to determine the maximum frame size used on the ELAN.  The value set on the LEC should not exceed the Maximum Frame Size set on the LES.

Caution:  Changing to a larger frame size causes the line card to restart.

6 In the Max Unkwn Frame Time field, specify the time period within which the maximum number of unknown frames is not to be exceeded. The range of acceptable values is 1 to 60 seconds.
7 In the Control Timeout field, specify the maximum amount of time the LEC waits for a response after sending a request. The range of acceptable values is 10 to 300 seconds. 

If this value is exceeded, the LEC issues another request.

8 In the Max Retry Cnt field, enter the number of times the LEC attempts to resend an LE ARP Request when the ARP Response Time is exceeded.
9 In the Aging Time field, enter the number of seconds each entry in the LE ARP cache is retained. The range of acceptable values is 10 to 300 seconds.
10 In the ARP Response Time field, enter the number of seconds within which the transmitting LEC expects to receive an LE ARP response after it sends and LE ARP Request. The range of acceptable values for this parameter is 1 to 30 seconds.

If the length of time it takes for the transmitting LEC to receive a response equals or exceeds the value entered here, the LEC initiates a retry.

11 In the ELAN Name field, enter the the name of the ELAN with which you want to associate (join) the LEC. Typically, a list of valid ELAN names is created by the LAN Emulation Configuration Server (LECS) network administrator.

If you do not identify which ELAN the LEC should join, the LECS directs the connection to a default ELAN compatible with the requirements of the interface.

12 In the Max Unkwn Frame Cnt field, specify the maximum number of unknown frames sent to the BUS.  The range of values is 1 to 10.
13 In the VCC Timeout field, set the maximum amount of time (in minutes) that a Data Direct VCC is allowed to be inactive (no data frame traffic is transmitted or received).

If the VCC timeout value is exceeded, the GS2000 LEC interface releases the VCC.

14 In the Path Swtch Delay field, enter the number of seconds after which an LEC assumes a data frame it transmits is either delivered to its destination, or discarded.  The range of acceptable values is 1 to 8 seconds.
15 In the Frwrd Dly Time field, enter the number of seconds each entry in the LE ARP cache is retained when a topology change is in progress.  The range of acceptable values is 4 to 30 seconds.
16 In the Flush Timeout field, enter the maximum amount of seconds the LEC waits to receive an LE Flush Response after it sends a request.  The range of acceptable values is 1 to 4 seconds.  The default is 4 seconds.

Configuring a Bridge Tunnel

To configure the ATM logical interface as a bridge tunnel, specify a VCI and click Change to Bridge Tunnel,  then click the Help button within the ATM Bridge Tunnel Configuration and Status window.

Performing Other ATM Interface Configuration Tasks

Use the CLI to perform the following optional ATM interface configuration tasks:

  • Setting the ATM Transmission Type to Synchronous Digital Hierarchy (SDH)  

    SDH is the frame format most commonly used in European countries. By default, the transmission type is set to Syncrhonous Optical Network (SONET), the frame format most commonly used in the United States. 

  • Manually Setting the ATM Transmission Timing 

    Transmission and receipt of SONET or SDH frames must be synchronized between the ATM interface and the other devices with which the line card communicates. The timing can be based on the system clock of the GIGAswitch, the Clock Management Module (CMM), or it can be based on the system clock of another device on the network. By default, transmission timing is based on the GIGAswitch system's CMM.

  • Disabling or Enabling Payload Scrambling

    Payload scrambling is a function used to help ensure data integrity at the level of the SONET or SDH payload envelope.  By default, payload scrambling is enabled.  If the GS2000 line card is to communicate with a DIGITAL GIGAswitch/FDDI AGL2, you must disable payload scrambling.

Field Descriptions

Status
MAC Type Frame type used by the ATM LEC. The frame type is always Ethernet.
ELAN Name (Configured) Name of the ELAN with which the LEC is associated.
ATM address ATM address for this ATM logical interface.
LEC Status Displays LEC port status.
ELAN Name (Joined) Name of the ELAN with which the LEC is associated.
Statistics
LE Arp Request Sent Number of LE ARP Requests sent by this LEC.
LE Arp Request Received Number of LE ARP Requests received by this LEC.
LEC Control Frames Sent Number of LEC control frames sent by this LEC.
LEC Control Frames Received Number of LEC control frames received by this LEC.
LEC Illegal Control Frames Received Number of illegal LEC control frames received by this LEC.
Virtual Circuits
Ifc Logical interface number associated with the interface. 
VPI Lists the Virtual Path Indentifier (VPI) associated with the interfaces listed in the Ifc column.
VCI Lists the Virtual Circuit Identifers (VCIs) associated with the interfaces listed in the Ifc column.
Type Indicates the type of virtual circuit, such as ILMI VC, LE Control VC, and so forth.
S/PVC Indicates whether the circuit is a switched virtual circuit (SVC) or a permanent virtual circuit (PVC).
ATM Address ATM address of the corresponding logical interface listed in the Ifc column.
ATM LEC Configuration
PHY Type PHY layer type.
Interface Specifies whether the interface is enabled or disabled.
Config Mode Specifies whether the LES address is configured automatically or manually.
LES Server Address for Manual Mode Specifies the address of the LAN Emulation Server (LES).
Max Frame Size Maximum data frame size the LEC can send on a Multicast Send VCC, or receive on the Multicast Send VCC or the Multicast Forward VCC. This parameter also specifies the maximum frame size for all LEC Data Direct VCCs.

Note: ELAN services require that the maximum frame size is the same for all LECs belonging to a specific ELAN.   All LECs that are members of an ELAN participate in a negotation process to determine the maximum frame size used on the ELAN. The value set on the LEC should not exceed the Maximum Frame Size set on the LES.

Max Unkwn Frame Time Period within which the maximum number of unknown  frames is not to be exceeded.
Control Timeout Timeout value of LECS and LES requests.
Max Retry Cnt Maximum number of times the LEC may attempt to resend an LE ARP Request when the ARP Response Time is exceeded.
Aging Time Length of time entries in the LE ARP cache are retained under normal operation.
ARP Response Time Maximum amount of time, in seconds, the LEC waits before retrying a LE ARP Request.
ELAN Name Name of the ELAN with which the LEC is associated.
Max Unkwn Frame Cnt Maximum number of unknown frames that an LEC can send to the BUS within the time period specified by the Max Unkwn Frame Time value.
VCC Timeout Maximum amount of time a Data Direct VCC is inactive (no data frame traffic is transmitted or received) before the VCC is released.
Path Swtch Delay Period of time after which the LEC assumes a transmitted data frame has been delivered to its destination or discarded.
Frwrd Dly Time Length of time entries in the LE ARP cache are retained when a topology change is in progress.
Flush Timeout Length of time, in seconds, the LEC waits to receive an LE Flush Response after it sends a request.