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Table Of Contents
Continuity Testing
The following sections are provided:
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Supported MIBs and RFCs on page 2
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Feature Summary
The Continuity Test (COT) subsystem supports the Continuity Test, which is required by the SS7 network to conduct loopback and tone check testing on the path before a circuit is established.
COT will detect any failure of DS0 channels. It is required for North American SS7 compliance.
List of Terms
COT—Continuity test. Used to test individual DS0 channels via either loopback or tone detection and generation.
DSP—Digital Signal Processor. Many firmware functions of a NAS are performed by DSPs which are generally provisioned as banks of shared resources among all the DS0s. Typical DSP functions include: data modems, voice CODECS, fax modems and CODECs, and low-level signaling (such as CAS/R2).
HDLC—High-Level Data Link Control.
ISP—Internet service provider.
NAS—Network access server. A Cisco platform (or collection of platforms such as an AccessPath system which interfaces between the packet world (for example, the Internet) and the circuit world (for example, the PSTN).
PSTN—Public Switched Telephone Network.
SAS—Signaling access server. A server which interfaces between the NAS and the SS7 signaling network.
SLM—Signaling link management.
SNIP—SAS NAS Interface Protocol.
SS7—Signaling System Number 7.
SSP—Service switching point. An element of an SS7-based Intelligent Network which performs call origination, termination, or tandem switching. The combined NAS/SAS system looks like a single SSP to the SS7 network.
STP—Signal transfer point. An element of an SS7-based Intelligent Network which performs routing of the SS7 signaling.
T1—A digital carrier used to transmit a DS-1 formatted digital signal at 1.544 MHz.
TDM—Time-division multiplexing. The transmission scheme employed by all manner of digital circuits in the PSTN.
TIC—Trunk identification code.
RLM—Redundant link manager.
VoIP—Voice over IP. The ability to carry normal telephony-style voice over an IP-based Internet with POTS-like functionality, reliability, and voice quality.
Restrictions
You must have installed MICA 2.6.1.0 portware, which supports the COT feature.
Platforms
The following hardware platforms support this feature:
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Supported MIBs and RFCs
None.
Functional Description
The SS7 (Signaling System Number 7) network, in order to detect failures of DS0 channels, will at times request a Continuity Test (COT) of a channel before establishing a call. ITU-based networks use only the loopback method for continuity test. However, ANSI-based network usage varies. Some use only the loopback method and others use both tone and loopback methods. For this release of the SS7 system, only the loopback method is supported.
Continuity test requests will be received over an SS7 signaling path and processed within the SAS (Signaling Access Server). The SAS will request that the NAS put the particular bearer in external loopback mode (loopback incoming receive to outgoing transmit) or to insert a transponder in the incoming circuit. The continuity test will last until a COT message is received.
Configuration Tasks
None.
Command Reference
The three new COT commands are show, clear, and debug. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command references.
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clear cot summary
Use the clear cot summary command to reset the counters.
clear cot summary
Syntax Description
This command has no keywords or arguments.
Command Mode
Privileged EXEC.
Usage Guidelines
This command first appeared in Cisco IOS Release 11.3(7).
Sample Display
There is no display generated, but the counters in the show cot summary command would be all zeros.
Related Commands
show cot dsp
show cot request
show cot summary
debug cotshow cot dsp
To display information about the COT DSP (Digital Signal Processor) configuration or current status, use the show cot dsp command.
show cot dsp { config | status } applique/ds0 (Cisco AS5200 and Cisco AS5300)
show cot dsp { config | status } shelf/slot/applique/ds0 (Cisco AS5800)Syntax Description
Command Mode
Privileged EXEC.
Usage Guidelines
This command first appeared in Cisco IOS Release 11.3(7).
Sample Display
The following is sample output from the show cot dsp command that shows the COT DSP configuration.
5300# show cot dsp status 1/1Rx Freq 2010 HxTx Freq 1780 HxTx then Rx modein WaitRxOn state5300# show cot dsp config 1/1Rx Freq 2010 HxTx Freq 1780 HxTx then Rx modeTimeout value:0describes the fields in these displays.
Related Commands
clear cot summary
show cot request
show cot summary
debug cotshow cot request
To display information use the show cot request command.
show cot request shelf/slot/applique/ds0 (Cisco AS5200 and Cisco AS5300)
show cot request applique/ds0 (Cisco AS5800)Syntax Description
Command Mode
Privileged EXEC.
Usage Guidelines
This command first appeared in Cisco IOS Release 11.3(7).
Sample Display
The following is sample output from the show cot request command.
5300# show cot request 1/100:19:29:COT Request@ 0x61064A20, CDB@ 0x60EBB48C, Params@0x61123DBC00:19:29: request type = COT_CHECK_TONE_ON00:19:29: shelf 0 slot 0 appl_no 1 ds0 100:19:29: duration 100000 key FFF1 freqTx 1780 freqRx 201000:19:29: state COT_WAIT_TD_ON_CT00:19:29: event_proc(0x6093B55C)describes the fields in these displays.
Related Commands
clear cot summary
show cot dsp
show cot summary
debug cotshow cot summary
To display information about the COT activity, use the show cot summary command.
show cot summary
Syntax Description
This command has no keywords or arguments.
Command Mode
Privileged EXEC.
Usage Guidelines
This command first appeared in Cisco IOS Release 11.3(7).
Sample Display
The following is sample output from the show cot summary command that shows the COT DSP configuration.
5300# show cot summaryrouter#08:23:24: COT Subsystem - Request Statistics08:23:24: COT Request Type = COT_DS0_LOOPBACK_ON08:23:24: # of request(s) : 4 # of restart requests(s) : 008:23:24: # of successful request(s): 4 # of invalid request(s) : 008:23:24: # of cot timeout(s) : 0 # of dsp error(s) : 008:23:24: # of no dsp(s) : 008:23:24: COT Request Type = COT_DS0_LOOPBACK_OFF08:23:24: # of request(s) : 4 # of restart requests(s) : 008:23:24: # of successful request(s): 4 # of invalid request(s) : 008:23:24: # of cot timeout(s) : 0 # of dsp error(s) : 008:23:24: # of no dsp(s) : 008:23:24: COT Request Type = COT_CHECK_TONE_ON08:23:24: # of request(s) : 7 # of restart requests(s) : 008:23:24: # of successful request(s): 3 # of invalid request(s) : 208:23:24: # of cot timeout(s) : 1 # of dsp error(s) : 008:23:24: # of no dsp(s) : 008:23:24: COT Request Type = COT_CHECK_TONE_OFF08:23:24: # of request(s) : 0 # of restart requests(s) : 008:23:24: # of successful request(s): 0 # of invalid request(s) : 008:23:24: # of cot timeout(s) : 0 # of dsp error(s) : 008:23:24: # of no dsp(s) : 008:23:24: COT Request Type = COT_CUT_IN_TRANSPONDER08:23:24: # of request(s) : 0 # of restart requests(s) : 008:23:24: # of successful request(s): 0 # of invalid request(s) : 008:23:24: # of cot timeout(s) : 0 # of dsp error(s) : 008:23:24: # of no dsp(s) : 008:23:24: COT Request Type = COT_CUT_OUT_TRANSPONDER08:23:24: # of request(s) : 0 # of restart requests(s) : 008:23:24: # of successful request(s): 0 # of invalid request(s) : 008:23:24: # of cot timeout(s) : 0 # of dsp error(s) : 008:23:24: # of no dsp(s) : 0describes the fields in these displays.
Related Commands
clear cot summary
show cot dsp
show cot request
debug cotDebug Commands
debug cot
Use the debug cot command to display information about the COT functionality. The no form of this command disables debugging output.
debug cot { api | dsp | queue | detail }
no debug cotSyntax Description
Usage Guidelines
This command first appeared in Cisco IOS Release 11.3(7).
Sample Display
shows sample debug cot api output.
Figure 1 Sample Debug COT API Output
5300# debug cot apiCOT API debugging is on08:29:55: cot_request_handler(): CDB@0x60DEDE14, req(COT_CHECK_TONE_ON):08:29:55: shelf 0 slot 0 appl_no 1 ds0 108:29:55: freqTX 2010 freqRX 1780 key 0xFFF1 duration 60000describes the fields in these displays.
shows sample debug cot dsp output.
Figure 2 Sample Debug COT DSP Output
5300# debug cot dsp5300#00:10:42:COT:DSP (1/1) Allocated00:10:43:In cot_callback00:10:43: returned key 0xFFF1, status = 000:10:43:COT:Received DSP Q Event00:10:43:COT:DSP (1/1) Done00:10:43:COT:DSP (1/1) De-allocateddescribes the fields in these displays.
shows sample debug cot queue output.
Figure 3 Sample Debug COT Queue Output
5300# debug cot queue5300#00:11:26:COT(0x60EBB48C):Adding new request (0x61123DBC) to InProgress Q00:11:26:COT(0x60EBB48C):Adding COT(0x61123DBC) to the Q head00:11:27:In cot_callback00:11:27: returned key 0xFFF1, status = 0describes the fields in these displays.
Table 6 Debug COT Queue Field Descriptions
COT
Internal COT operation request.
Adding new request
Internal COT operation request queue.
shows sample debug cot detail output.
Figure 4 Sample Debug COT Detail Output
5300# debug cot detail5300#00:04:57:cot_request_handler():CDB@0x60EBB48C, req(COT_CHECK_TONE_ON):00:04:57: shelf 0 slot 0 appl_no 1 ds0 100:04:57: freqTX 1780 freqRX 2010 key 0xFFF1 duration 100000:04:57:COT:DSP (1/0) Allocated00:04:57:COT:Request Transition to COT_WAIT_TD_ON00:04:57:COT(0x60EBB48C):Adding new request (0x61123DBC) to InProgress Q00:04:57:COT(0x60EBB48C):Adding COT(0x61123DBC) to the Q head00:04:57:COT:Start Duration Timer for Check Tone Request00:04:58:COT:Received Timer Event00:04:58:COT:T24 Timer Expired00:04:58:COT Request@ 0x61123DBC, CDB@ 0x60EBB48C, Params@0x61123E0800:04:58: request type = COT_CHECK_TONE_ON00:04:58: shelf 0 slot 0 appl_no 1 ds0 100:04:58: duration 1000 key FFF1 freqTx 1780 freqRx 201000:04:58: state COT_WAIT_TD_ON_CT00:04:58: event_proc(0x6093B55C)00:04:58:Invoke NI2 callback to inform COT request status00:04:58:In cot_callback00:04:58: returned key 0xFFF1, status = 000:04:58:Return from NI2 callback00:04:58:COT:Request Transition to IDLE00:04:58:COT:Received DSP Q Event00:04:58:COT:DSP (1/0) Done00:04:58:COT:DSP (1/0) De-allocatedBecause debug cot detail is a summary of debug cot api, debug cot dsp, and debug cot queue, the field descriptions are the same.
What to Do Next
For additional software configuration information, see the following publications:
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