Usage Guidelines

When the line is placed in administrative shutdown state, use the ais-shut command to send a signal to downstream equipment that indicates that there is a problem with the line.

The ais-shut command is ignored if automatic protection switching (APS) is running for the corresponding port, because the setting must be enabled for proper APS operation.

For SONET ports that do not have hardware support for LAIS insertion, the ais-shut command is disabled.

Usage Guidelines

Use the ais-shut command to enable automatic insertion of PAIS in the appropriate sent SONET path overhead whenever the corresponding SONET path enters the administratively down state.

Usage Guidelines

In a multirouter APS topology, a manual or force request is supported only on the protect router.

Specify 0 or 1 to identify on which channel the traffic should be stopped and switched to the other channel. Therefore, force 0 or manual 0 moves traffic from the protect to the working channel, and force 1 or manual 1 moves traffic from the working to the protect channel.

Use the force keyword to manually switch the traffic to a protect channel. For example, if you need to change the fiber connection, you can manually force the working channel to switch to the protect interface.

A forced switch can be used to override an automatic (Signal Failed Signal Degraded) or a manual switch request. A lockout request (using the lockout command) overrides a force request.

Note	If a request of equal or higher priority is in effect, you cannot use the force keyword to initiate a forced APS request at the local end of the SONET link.

Use the manual keyword to manually switch the circuit to a protect channel. For example, you can use this feature when you need to perform maintenance on the working channel. If a protection switch is already up, you can also use the manual keyword to revert the communication link to the working channel before the wait to restore (WTR) time period has expired. The WTR time period is set by the revert command. Use the no form of this command to cancel the switch.

A manual switch request can be used to control which channel carries the traffic when no other higher-priority user-initiated or automatic requests are in effect.

The manual request has the lowest priority among all user-initiated or automatic requests. Any other such requests override a manual request.

Usage Guidelines

An APS group contains one protect (P) SONET port and one working (W) SONET port. The working and protect ports can reside on the same logical channel (LC), on different LCs in the same router, or on different routers. One APS group must be configured for each protect port and its corresponding working ports.

Use the aps group (global) command to enter APS group configuration mode and configure APS connections with other SONET equipment.

Usage Guidelines

Use the authenticate command to configure the authentication string for the PGP message exchange between the protect and working routers. Use the no form of this command to revert to the default authentication string.

The authenticate command applies only in multirouter automatic protection switching (APS) group configurations.

In multirouter APS topologies, the protect and working routers communicate with each other through the User Datagram Protocol (UDP)-based Pretty Good Privacy protocol. Each Pretty Good Privacy packet contains an authentication string used for packet validation. The authentication string on all routers involved in the same APS group operation must match for proper APS operation.

Usage Guidelines

No specific guidelines impact the use of this command.

Usage Guidelines

For the interface-path-id argument, use the following guidelines:

• If specifying a physical interface, the naming notation is rack/slot/module/port. The slash between values is required as part of the notation. An explanation of each component of the naming notation is as follows:

  • rack : Chassis number of the rack.

  • slot : Physical slot number of the line card.

  • module : Module number. A physical layer interface module (PLIM) is always 0.

  • port : Physical port number of the interface.

• If specifying a virtual interface, the number range varies, depending on interface type.

Use the channel local command to designate SONET physical ports as SONET APS channels in the current APS group. Use the channel remote command to assign channels that are physically located in a different router.

Preconfigured interfaces are supported.

If the protect channel is local, it must be assigned using a channel command before any of the working channels are assigned. The reason is that having only a working channel assigned is a valid configuration for a working router in a multirouter APS topology and further attempts to configure a local protect channel are rejected.

The interface type must be a SONET controller.

Usage Guidelines

Use the channel remote command to assign working or protect channels that are physically located in a different router.

Use the channel local command to assign channels in the local router.

Note	The channel remote command should not be used in single-router APS topologies.

The IP address of the remote router is required only if a working channel configured as the protect router contacts all working routers.

Specifying a remote protect channel is optional. If you do not specify a remote protect channel, the default value of 0.0.0.0 is used. The protect router is always the one that contacts the working router. The working router replies to the protect router using the source address extracted from the incoming messages as the destination address. If an address other than 0.0.0.0 (the default value) is specified, the working router always uses that address when sending messages to the protect router.

Usage Guidelines

For the interface-path-id argument, use the following guidelines:

• If specifying a physical interface, the naming notation is rack/slot/module/port. The slash between values is required as part of the notation. An explanation of each component of the naming notation is as follows:

  • rack : Chassis number of the rack.

  • slot : Physical slot number of the line card.

  • module : Module number. A physical layer interface module (PLIM) is always 0.

  • port : Physical port number of the interface.

• If specifying a virtual interface, the number range varies, depending on interface type.

Use the clear counters sonet command to clear SONET counters for a specific SONET controller.

Usage Guidelines

Use the clock source command to configure which reference clock is used by the sender.

Usage Guidelines

For the interface-path-id argument, use the following guidelines:

• If specifying a physical interface, the naming notation is rack/slot/module/port. The slash between values is required as part of the notation. An explanation of each component of the naming notation is as follows:

  • rack : Chassis number of the rack.

  • slot : Physical slot number of the line card.

  • module : Module number. A physical layer interface module (PLIM) is always 0.

  • port : Physical port number of the interface.

• If specifying a virtual interface, the number range varies, depending on interface type.

Use the path (SONET) command to enter SONET/SDH path configuration mode to specify other SONET options for a SONET path.

Usage Guidelines

No specific guidelines impact the use of this command.

Usage Guidelines

If the timer for the STS path delay trigger expires, an alarm is declared.

Usage Guidelines

This command does not have a no form.

Usage Guidelines

Note	If a request of equal or higher priority is in effect, you cannot use the force command to initiate a forced APS request at the local end of the SONET link.

Use the force command to manually switch the traffic to a protect channel. For example, if you need to change the fiber connection, you can manually force the working channel to switch to the protect interface.

The 0 or 1 keyword (by default 1) identifies on which channel the traffic should be stopped and moved on the protect channel. The force 1 command moves traffic from the working channel to the protect channel; the force 0 command moves traffic from the protect channel back to the working channel.

A forced switch can be used to override an automatic (Signal Failed Signal Degraded) or a manual switch request. A lockout request (via the lockout command) overrides a force request.

In a multirouter APS topology, a force request is allowed only on the protect router.

This command remains in effect until it is unconfigured by using the no form of the command.

Usage Guidelines

Use the framing command to select either SONET or SDH framing on the selected physical port, if supported. For physical ports that do not support either of these two options, the framing command is disabled.

Use the no form of this command to disable SONET or SDH framing on the SONET controller.

Usage Guidelines

If the timer for the SONET/SDH line delay clear expires, an alarm is cleared.

Usage Guidelines

If the timer for the SONET/SDH line delay trigger expires, an alarm is raised.

Usage Guidelines

A lockout switch request can be used to override a force, an automatic (Signal Failed or Signal Degraded), or a manual switch request. No other request can override a lockout request; it has the highest possible priority.

In a multirouter APS topology, a lockout request is allowed only on the protect router.

This command remains in effect until it is unconfigured by using the no form of the command.

Usage Guidelines

The SONET and Synchronous Digital Hierarchy (SDH) transport layers support two loopback operation modes for diagnostic purposes: internal and line. In the terminal (internal) loopback, the sent signal is looped back to the receiver. In the facility (line) loopback, the signal received from the far end is looped back and sent on the line. The two loopback modes cannot be active at the same time. In normal operation mode, neither of the two loopback modes is enabled.

Usage Guidelines

Use the manual command to manually switch the circuit to a protect channel. For example, you can use this feature when you need to perform maintenance on the working channel. If a protection switch is already up, you can also use the manual command to revert the communication link to the working channel before the wait to restore (WTR) time period has expired. The WTR time period is set by the revert command. Use the no form of this command to cancel the switch.

A manual switch request can be used to control which channel carries the traffic when no other higher-priority user-initiated or automatic requests are in effect.

The 0 or 1 keyword identifies the channel from which the traffic should be moved on the protect channel:

• The manual 1 command moves traffic on to the protect channel.
• The manual 0 command moves traffic on to the working channel.

The manual request has the lowest priority among all user-initiated or automatic requests. Any other such requests override a manual request.

In a multirouter APS topology a manual request is allowed only on the protect router.

This command remains in effect until it is unconfigured by using the no form of the command.

Usage Guidelines

Use the overhead command to set the SONET overhead bytes in the frame header to a specific standards requirement.

Use the no form of this command to remove the setting of the SONET overhead bytes from the configuration file and restore the default condition.

For the j0 keyword, the value that you use for the trace byte depends on the type of equipment being used. For the s1s0 keyword, the value that you use depends on whether you are using the SONET or SDH mode. For SONET mode, use the value 0 (the default). For SDH mode, use the value 2.

Usage Guidelines

The SONET standards permit or require user access for configuration of some bytes or bits in the SONET path overhead. Use the overhead command to set the SONET path overhead bytes in the frame header to a specific standards requirement. Use the no form of this command to remove the setting of the SONET path overhead bytes from the configuration file and restore the system to its default condition.

Use the c2 keyword to configure the desired C2 byte value in the SONET path overhead.

Use the j1 keyword to configure a user-defined path trace message in the j1 bytes of the SONET path overhead. For the j1 keyword, use the default message or insert your own message that has a maximum of 62 characters. If no user-defined message is configured, a default message is automatically generated, containing the router name, the controller name, its IP address, and the values of the sent and received K1 and K2 bytes in the SONET line overhead.

Usage Guidelines

No specific guidelines impact the use of this command.

Usage Guidelines

If the timer for the SONET/SDH path delay trigger expires, an alarm is declared.

Usage Guidelines

No specific guidelines impact the use of this command.

Usage Guidelines

Reporting an alarm means that the alarm can be logged to the console, but it is no guarantee that it is logged. SONET alarm hierarchy rules dictate that only the most severe alarm of an alarm group is reported. Whether an alarm is reported or not, you can check the current state of masked alarm, a problem indication that is a candidate for an alarm, by displaying the “Masked Alarms” line in the show controllers sonet command output.

For B1, the bit interleaved parity (BIP) error report is calculated by comparing the BIP-8 code with the BIP-8 code that is extracted from the B1 byte of the following frame. Differences indicate that section-level bit errors have occurred.

For B2, the BIP error report is calculated by comparing the BIP-8/24 code with the BIP-8 code that is extracted from the B2 byte of the following frame. Differences indicate that line-level bit errors have occurred.

Path AIS is sent by line terminating equipment to alert the downstream path terminating equipment (PTE) that it has detected a defect on its incoming line signal.

Path loss of pointer (LOP) is reported as a result of an invalid pointer (H1, H2) or an excess number of new data flag enabled indications.

SLOF is detected when an error-framing defect on the incoming SONET signal persists for 3 microseconds.

SLOS is detected when an all-zeros pattern on the incoming SONET signal is observed. This defect might also be reported if the received signal level drops below the specified threshold.

To determine the alarms that are reported on the controller, use the show controllers sonet command.

Usage Guidelines

Reporting an alarm means that the alarm can be logged to the console, but it is no guarantee that it is logged. SONET alarm hierarchy rules dictate that only the most severe alarm of an alarm group is reported. Whether an alarm is reported or not, you can view the current state of a masked alarm, a problem indication that is a candidate for an alarm, by inspecting the “Masked Alarms” line displayed in the show controllers sonet command output.

For B3, the bit interleaved parity (BIP) error report is calculated by comparing the BIP-8 code with the BIP-8 code that is extracted from the B3 byte of the following frame. Differences indicate that path-level bit errors have occurred.

Path AIS is sent by line-terminating equipment to alert the downstream path-terminating equipment (PTE) that it has detected a defect on its incoming line signal.

Path LOP is reported as a result of an invalid pointer (H1, H2) or an excess number of new data flag enabled indications.

To determine the alarms that are reported on the controller, use the show controllers sonet command.

All report commands accept the default option. The default reporting values are determined based upon the SONET standards specifications and are clearly identified in the corresponding command’s help string.

Note	The reporting of B3 BER TCA errors and path LOP errors is enabled by default.

Usage Guidelines

Use the revert command to enable and disable revertive APS operation mode, if needed. The revertive APS operation mode of the routers should be matched with the APS operation mode of the connected SONET equipment. Use the no form of this command to disable automatic switchover.

The revertive APS operation mode is the recommended operation mode because it offers better traffic protection during various possible software failures and upgrade or downgrade scenarios.

The minutes argument indicates how many minutes will elapse until automatic protection switching (APS) decides to switch traffic back from protect to working after the condition that caused an automatic (Signal Failed or Signal Degrade) switch to protect disappears. A value of 0 (default) disables APS revertive mode.

In a multirouter APS topology, the revert command is allowed only on the protect router.

Usage Guidelines

SONET payload scrambling applies a self-synchronous scrambler (x43+1) to the synchronous payload envelope (SPE) of the controller to ensure sufficient bit transition density. Both ends of the connection must be configured using SONET path scrambling.

If the hardware payload scrambling support is not user-configurable, or is not supported, the scrambling disable command may be rejected.

Usage Guidelines

Use the show aps command to display operational status for all configured SONET APS groups.

Displaying the SONET APS operational data is considered of lower priority than the APS operation itself. Because the information is collected from several sources scattered across the various nodes involved, there is a small probability that some states will change while the command is being run.

The command should be reissued for confirmation before decisions are made based on the results displayed.

Usage Guidelines

Use the show aps agents command to display the status of the APS WP distributed communication subsystem.

The WP communication is critical for the APS functionality. The show aps agents command is typically used as a debugging aid for unexpected or unusual APS operation.

Displaying the APS operational data is considered of lower priority than the APS operation itself. Because the information is collected from several sources scattered across the various nodes involved, there is a small probability that some states will change while the command is being run.

The command should be reissued for confirmation before decisions are made based on the results displayed.

Usage Guidelines

The show aps group command displays information about APS groups, and is useful if multiple APS groups are configured.

Displaying the APS operational data is considered of lower priority than the APS operation itself. Because the information is collected from several sources scattered across the various nodes involved, there is a small probability that some states will change while the command is being run.

The command should be reissued for confirmation before decisions are made based on the results displayed.

Usage Guidelines

For the interface-path-id argument, use the following guidelines:

• If specifying a physical interface, the naming notation is rack/slot/module/port. The slash between values is required as part of the notation. An explanation of each component of the naming notation is as follows:

  • rack : Chassis number of the rack.

  • slot : Physical slot number of the line card.

  • module : Module number. A physical layer interface module (PLIM) is always 0.

  • port : Physical port number of the interface.

• If specifying a virtual interface, the number range varies, depending on interface type.

The information displayed is generally useful for diagnostic tasks performed by technical support personnel only.

Usage Guidelines

For the interface-path-id argument, use the following guidelines:

• If specifying a physical interface, the naming notation is rack/slot/module/port. The slash between values is required as part of the notation. An explanation of each component of the naming notation is as follows:

  • rack : Chassis number of the rack.

  • slot : Physical slot number of the line card.

  • module : Module number. A physical layer interface module (PLIM) is always 0.

  • port : Physical port number of the interface.

• If specifying a virtual interface, the number range varies, depending on interface type.

Use the show controllers sonet command to display information about the operational status of SONET layers on a particular SONET port.

If the manageability PIE is not installed, you can use the show controllers sonet command to display the counters for the current 15 minutes only without history data. However, the SONET MIB is still available but is limited to the current bucket of data. History data is still available only when the manageability PIE is loaded. The show controllers sonet command is available at any time to display current data, and history data is stored in the line card rather in the history bucket.

Usage Guidelines

Use the shutdown command to shut down a SONET controller and disable SONET controller processing. Use the no shutdown command to bring back up a SONET controller and enable SONET controller processing.

The SONET controller must be brought up for the proper operation of the Layer 2 interface. The Layer 2 interface has a separate shutdown command available, which does not operate on the SONET controller’s administrative state.

Usage Guidelines

By default, APS uses the signaling mode matching the framing mode. The signalling command may be required, depending upon the transport equipment capabilities, only on “transition” links interconnecting SONET and SDH networks.

In a multirouter APS topology, the signalling command is allowed only on the protect router.

Usage Guidelines

Use the timers command to change the time between hello packets and the time before the protect interface process declares a working interface router to be down.

The hello time, in seconds, represents the interval between the periodic message exchange between the Protect Group Protocol (PGP) peers. The hold time, in seconds, represents the maximum interval starting with the first failed periodic message after which, if no successful exchange takes place, the PGP link is declared dead. If the Hello timer is X seconds and Hold Timer is configured as Y seconds (where, X < Y), then the PGP link down announcement happens in a minimum of Y-X seconds and maximum of Y seconds.

If many multirouter APS groups are configured and the CPU load or the User Datagram Protocol (UDP) traffic associated with the PGP communication is considered too high, then the hello interval should be increased.

Increasing the hold time is suggested if the PGP link is flapping. The possible causes include high route processor (RP) CPU load, high traffic, or high error rates on the links between the working and the protect routers.

We recommend that you have a hold time at least three times longer than the hello time (allowing three or more consecutive failed periodic message exchange failures).

The timers command is typically used only on the protect router. After the PGP connection is established, the working router learns about the timer settings from the protect router and automatically adjusts accordingly, regardless of its own timer configuration.

The timers command is meaningful only in multirouter automatic protection switching (APS) topologies and is ignored otherwise.

Usage Guidelines

For B1, the bit interleaved parity (BIP) error report is calculated by comparing the BIP-8 code with the BIP-8 code that is extracted from the B1 byte of the following frame. Differences indicate that section-level bit errors have occurred.

For B2, the BIP error report is calculated by comparing the BIP-8/24 code with the BIP-8 code that is extracted from the B2 byte of the following frame. Differences indicate that line-level bit errors have occurred.

Signal failure BER and signal degrade BER are sourced from B2 BIP-8 error counts (as is B2-TCA). The b1-tca and b2-tca keywords print only a log message to the console (if reports for them are enabled).

To determine the BER thresholds configured on the controller, use the show controllers sonet command.

Usage Guidelines

For B3, the bit interleaved parity (BIP) error report is calculated by comparing the BIP-8 code with the BIP-8 code that is extracted from the B3 byte of the following frame. Differences indicate that path-level bit errors have occurred.

In addition to BIP errors detected at the local end in the receive direction, B3 error counts detected in the G1 byte (P-REI or P-FEBE) by the far-end SONET equipment are returned.

The b3-tca keyword prints only a log message to the console (if reports for them are enabled).

Usage Guidelines

Use the uneq-shut command to disable automatic insertion of P-UNEQ code in the sent SONET path overhead C2 byte whenever the SONET path enters the administratively down state.

Usage Guidelines

Use the unidirectional command to configure a protect interface for unidirectional mode. Use the no form of this command to restore the default setting.

The unidirectional or bidirectional automatic protection switching (APS) operation mode of the routers should be matched with the APS operation mode of the connected SONET equipment.

Note

We recommend using bidirectional APS mode when it is supported by the interconnecting SONET equipment. When the protect interface is configured as unidirectional, the working and protect interfaces must cooperate to switch the transmit and receive SONET channel in a bidirectional fashion. Cooperation occurs automatically when the SONET network equipment is in bidirectional mode.

In a multirouter APS topology, the unidirectional command is allowed only on the protect router.