SL-SONET-APS-MIB: View SNMP OID List / Download MIB

This MIB module describes the SiteLight SONET APS.

This table contains objects to configure APS (Automatic Protection Switching) feature in a SONET Line. APS is the ability to configure a pair of SONET lines for redundancy so that the hardware will automatically switch the active line from working line to the protection line or vice versa, within 50ms, when the active line fails.

An entry is created during startup if the SEEP specifies that there are two trunk ports. The value of slSonetApsEnable determines if the APS is configured or not.

When a pair of APS lines is configured, one line has to be the working line, which is the primary line, and the other has to be the protection line, which is the backup line. This object refers to the working line in the APS pair.

The protection line indicates that it will become the active line when an APS switch occurs (APS switch could occur because of a failure on the working line).

This object is used to enable or disable the APS feature on the working/protection line pairs.

This object is used to configure APS architecture mode on the working/protection line pairs (read-write). All of the following are supported on single slot. oneToOne(2) is not supported across 2 slots,i.e. the working and protection slot numbers must be the same in oneToOne(2). onePlusOne : This can be supported on the same card and across 2 cards. This mode means that the transmit and receive signals go only over the active line(which could be working or protection line). (straight cable implied) oneToOne : This is supported only on the same card This mode means that the transmit and receive signals go over the working and protection lines. (straight cable implied).

This object indicates which Rx line is currently active. It could be the working line, the protection line or none if neither working nor protection line is active. This object reflects the status of receive direction.

This object indicates which Tx line is currently active. It could be the working line, the protection line or none if neither working nor protection line is active. This object reflects the status of receive direction. Not relevant for 1+1.

This object contains interval in minutes to wait before attempting to switch back to working line. Not applicable if the line is configured in non-revertive mode, i.e. protection line will continue to be active, even if failures on the working line are cleared. The framer clears the signal-fault and signal-degrade when APS switch occurs. Please refer to slSonetApsRevertive for description of non-revertive (read-write).

This object is used to configure the switching direction which this APS line supports (read-write). Unidirectional : APS switch only in one direction. Bidirectional : APS switch in both ends of the line.

This object is used to configure the APS revertive or nonrevertive option (read-write). revertive : Will switch the working line back to active state after the Wait-To-restore interval has expired and the working line Signal-Fault/Signal-Degrade has been cleared. Please refer to slSonetApsWaitToRestore for description of Wait-To-Restore interval. nonrevertive : The protection line continues to be the active line, The active line does not switch to the working line.

This object shows the actual APS direction that is implemented on the Near End terminal. APS direction configured through slSonetApsDirection is negotiated with the Far End and APS direction setting acceptable to both ends is operational at the Near End.

This object shows the actual APS architecture mode that is implemented on the Near End terminal. APS architecture mode configured through slSonetApsArchMode object is negotiated with the Far End through APS channel. Architecture mode acceptable to both the Near End and the Far End terminals is then operational at the Near End. This value can be different than the APS Architecture mode configured.

Indicates the current state of the port. lockedOut This bit, when applied to a working channel, indicates that the channel is prevented from switching to the protection line. When applied to the null channel, this bit indicates that no working channel may switch to the protection line. sdWorking A signal degrade condition on the working line is in effect. sdProtecting A signal degrade condition on the protecting line is in effect. sfWorking A signal failure condition on the working line is in effect. sfProtecting A signal failure condition on the protecting line is in effect. switched The switched bit is applied to a working channel if that channel is currently switched to the protection line. remoteRequest The switch request was initiated by the remote NE.

A count of Signal Degrade conditions. This condition occurs when the line Bit Error Rate exceeds the currently configured threshold.

A count of Signal Failure conditions that have been detected on the incoming signal. This condition occurs when a loss of signal, loss of frame, AIS-L or a Line bit error rate exceeding 10^-3 is detected on an incoming line.

The value of sysUpTime when this channel last completed a switch to the protection line. If this channel has never switched to the protection line, or this channel is the protection line, the value 0 will be returned.

The Sonet APS line failure code status - this is the status of failure encountered by the APS line. slSonetApsChannelMismatch: trasmitted K1 byte and received K2 byte do not match. slSonetApsProtectionByteFail: It could mean either K1 byte with invalid type of switch request bits was received, or, priority of received K1 byte is lower than the transmitted K1 byte. slSonetApsFEProtectionFailure: Remote end error detected. slSonetApsModeMismatch: Mismatch of Bit 5 of the K2 Byte.

A switch command initiates one external request for evaluation (read-write). (1) Clear - Clears all switch commands on the channel. (2) Lockout Of Protection - Prevents any of the working channels from switching to the protection line by issuing a Lockout of Protection request [unless a request of equal priority (i.e., a Lockout of Protection) is already in effect]. (3) Forced Switch of Working (to Protection) - Switches the working channel to the protection line unless a request of equal or higher priority is in effect, by issuing a Forced Switch request. (4) Forced Switch of Protection (to Working) - Switches the working channel back from the protection line to the working line unless a request of equal or higher priority is in effect, by issuing a Forced Switch request. This command applies only in the 1+1 architecture. (5) Manual Switch of Working (to Protection) - Switches the working channel to the protection line unless a request of equal or higher priority is in effect, by issuing a Manual Switch request. (6) Manual Switch of Protection (to Working) - Switches the working channel back from the protection line to the working line unless a request of equal or higher priority is in effect, by issuing a Manual Switch request. This command applies only in the 1+1 architecture for the null. (7) Exercise - Exercises the protocol for a protection switch unless a request of equal or higher priority is in effect, by issuing an Exercise request and checking the response on the APS channel. Reading this variable always returns zero (0).

The reason why APS switch happened. When the working line on one end fails, its other end is told to do an APS switch. The following options in the increasing order of priority indicate what type of switch request it is. slSonetApsRevertive : Switch back to working line after the Wait-to-Restore interval is over, and failures are cleared. It is the lowest priority. slSonetApsManual : Manual switch causes APS switch unless a request of equal or higher priority is in effect. slSonetApsSignalDefectLow : Switch happened because threshold for slSonetApsSigFaultBER was exceeded. slSonetApsSignalDefectHigh : Same as above, but higher priority. slSonetApsSignalFailureLow : Switch happened because threshold for slSonetApsSigDegradeBER was exceeded. slSonetApsSignalFailureHigh : Same as above, but higher priority. slSonetApsForceSwitch : Forced switch forces hardware to switch the active line even if the other line (could be working line or protection line) is in alarm. slSonetApsLockOut : This is the highest priority switch. This will override all other requests. slSonetApsRemoteRequest : indicates that the local switchover was in response to a remote request to switch. slSonetApsLockOut : indicates that the last switchover to the working occurred because of protection lockout.

Setting this variable to 1 will cause the counters on all of the SONET APS Config Table to be initialized to zero (read-write).

The Active Switch APS request: slSonetApsRevertive : Switch back to working line after the Wait-to-Restore interval is over, and failures are cleared. It is the lowest priority. slSonetApsManual : Manual switch causes APS switch unless a request of equal or higher priority is in effect. slSonetApsSignalDefectLow : Switch happened because threshold for slSonetApsSigFaultBER was exceeded. slSonetApsSignalDefectHigh : Same as above, but higher priority. slSonetApsSignalFailureLow : Switch happened because threshold for slSonetApsSigDegradeBER was exceeded. slSonetApsSignalFailureHigh : Same as above, but higher priority. slSonetApsForceSwitch : Forced switch forces hardware to switch the active line even if the other line (could be working line or protection line) is in alarm. slSonetApsLockOut : This is the highest priority switch. This will override all other requests. slSonetApsRemoteRequest : indicates that the local switchover was in response to a remote request to switch. slSonetApsLockOut : indicates that the last switchover to the working occurred because of protection lockout.

This variable contains the result of the last exercise command. True - means test success. False - otherwise.

An slSonetApsTrapSwitchover notification is sent when the value whenever a switchover occures.

An slSonetApsTrapChannelMismatch notification is sent when the APS failure code status is changed.

An slSonetApsTrapSwitchover notification is sent when the value of slSonetApsEnable is changed.