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Configuring Bundle Failover Between CTP Devices at Both the Local and Remote Sites (CTP Menu)

 

A CTP series device provides two types of Y-cable redundancy.

  • Redundancy by using a hardware link that uses a special Y cable—A hardware link requires a special Y cable that connects the CTP devices and is supported only on serial ports. The functioning of a hardware link is similar to the default operation of the redundancy feature in CTPOS Release 6.5 and earlier. A hardware link is supported only on serial ports.

  • Redundancy based on a software link that does not depend on a signaling hardware like the Y cable—A software link does not require a special signaling hardware. Y-cable port pairs can maintain contact with each other by means of OAM packets instead of a hardware signaling path. Because of this, Y-cable redundancy is supported on T1E1 ports as well as serial ports with a special Y cable. Redundancy by means of a software link is supported on both serial and T1/E1 ports on a CTP150 and CTP2000 devices.

To set up Y-cable redundancy at both the local and remote sites, you configure two bundles—a primary bundle and a backup bundle. Each bundle follows a different path between the two sites, as shown in Figure 1.

Figure 1: Y-Cable Redundancy at Both the Local and Remote Sites
Y-Cable Redundancy at Both
the Local and Remote Sites

When you configure Y-cable redundancy that uses a hardware link, you can use different redundant port numbers if the devices are using the same port on the 100-pin connector. For example, a Y cable 100-pin connector could be attached to ports 0-3 on the primary CTP device, with the second connector attached to ports 8-11 on the backup CTP device. The redundant ports would be P0/P8, P1/P9, P2/P10, and P3/P11 on the primary CTP and backup CTP devices, respectively.

Redundancy is not supported on Y cable between CTPOS releases 6.2 and earlier. Whether the Y-cable configuration is both-ended or single-ended, the primary and backup bundles on the Y cable must either be 6.1 or below, or 6.2 and later. After a switchover from primary to backup, if the primary circuit comes up later, it will revert to the primary circuit automatically.

Before you begin:

  • Disable the bundle before you modify the bundle options.

To configure Y-cable redundancy for CTP bundles by using the CTP Menu:

  1. From the Main Menu, select 1) Bundle Operations.
  2. Select 1) CTP.
  3. Select a bundle from the list.

    If you select an active bundle, you are prompted to disable the bundle before configuring it.

  4. Select 3) Port Config.
  5. Select 4) Advanced Options > 19) Redundancy Options > 1) Redundancy Mode and configure the options as described in Table 1.

    Table 1: Y-Cable Settings in the CTP Menu

    FieldFunctionYour Action

    Redundancy Mode

    Displays a list of supported redundancy modes. See Redundancy Features Overview for a list of supported Y-cable redundancy configuration settings.

    Select one:

    • Disable—Y-cable redundancy is not enabled on this port.

    • eXclusive OR (XOR)—Redundancy is enabled. In this mode the Y cable is active only if the port is in RUNNING state and the serial port on the Y-cable link is not in RUNNING state. If both bundles are RUNNING, the Y cable remains inactive on both the ports.

    • ReVeRT (RVRT)—When you select this mode, a primary and a secondary path is enabled. The primary path drives the cable when its bundle is in RUNNING state, independent of the state of the secondary path. The secondary path is activated when the primary path is offline. Whenever the primary path comes back online, the path is switched back to the primary path.

    • NOnReVert (NORV)—When you select this mode, the circuit is not switched back to primary when the primary path comes back online after switching to secondary path. The circuit is switched to the primary path only when the secondary path fails.

    • Signal (SIG)—The primary path is activated only if the secondary CTS output is inactive. When CTS is active, secondary drives cable.

    Pri/Sec Link Type

    Specifies the link types for primary and back up bundle.

    Select one.

    • H/W link—When enabled, the Y-cable redundancy is supported only on serial ports, and the link between ports is a hardware signaling connection over a special Y cable that uses the output to cable(TM) and the input from cable(RL) to communicate redundancy state between port pairs, by using keepalive pulses. Its operation is similar to the default operation of the redundancy feature in CTPOS Release 6.5 and earlier.

    • S/W link—Allows Y-cable port pairs to maintain contact with each other by means of OAM packets instead of using a hardware signaling path. The software link has the following advantages:

      • The software link does not require a special signaling hardware, which means that Y-cable redundancy can be used on T1E1 ports as well and is not restricted to serial ports with a special Y cable. Serial ports can get TM/RL signals for user applications.

      • Software or OAM link packets can check link partners and identify configuration errors. They can also differentiate between dead and alive states.

    Primary/Secondary

    Specifies the primary and backup bundles.

    Configure a primary and a backup bundle. When the software link is enabled and link partners are specified, the software verifies that there is a matched primary and backup pair.

    Other Port on Y

    Specifies information about the other port of the redundant primary and backup pair.

    Specify the following parameters:

    • Enter IP address—Specify an IP address.

    • Enter card number—Specify a card number in the range 0 through 6.

    • Enter port number—Specify a port number in the range 0 through 23.

    Fast switch

    Allows fast switching in case of a failover. This feature is supported only on serial ports with hardware links.

    Fast switch is supported only in Hot standby in Revert redundancy mode and is valid only for a hardware link.

    Select y or n.