# CUCM CallManager SDL trace files Canonical: https://warmtransfer.net/knowledge/cucm-sdl-trace-files Last verified: 2026-09-22 In CUCM release 15, SDL stands for Signaling Distribution Layer trace and is supported for the Cisco CallManager and Cisco CTIManager services on Unified Communications Manager only[^36]. From CUCM 9.x onward, Cisco CallManager traces are written as a single interleaved set of SDL* files rather than separate SDL* and ccm* file sets[^38]. ## How it works Cisco Unified Serviceability supports 3 trace kinds: SDI (System Diagnostic Interface) trace, SDL trace, and Log4J trace for Java applications[^49]. In Cisco Unified CallManager 4.2(1) SDL trace covered Cisco CallManager, Cisco CTIManager and Cisco TFTP and SDI and SDL logs could be written in XML format; this no longer describes current releases, where SDL applies to CallManager and CTIManager only[^51]. CallManager trace settings are configured in Cisco Unified Serviceability under Trace > Configuration by selecting the server, the CM Services service group and the Cisco CallManager service[^48]. Trace settings for a service can be applied to every server in the cluster by checking Apply to All Nodes, with the Trace On check box enabling tracing[^1]. Cisco warns that enabling trace decreases system performance and should be done only for troubleshooting[^21]. CUCM service debug trace levels are cumulative in the order Error, Special, State Transition, Significant, Entry/Exit, Arbitrary, Detailed, each level tracing everything the previous level does plus more[^16]. The Error trace level traces alarm conditions and events and is used for traces generated in an abnormal path[^15]. The Detailed trace level traces all Arbitrary conditions plus detailed debugging information[^14]. In CUCM 9.x and later the default Debug Trace Level for the Cisco CallManager service is Detailed[^10]. In the default CallManager trace configuration the filters left disabled are Miscellaneous, SoftKey, Route or Hunt List, All GateWay, SCCP Keep Alive, SpeedDial and SIP Keep Alive (REGISTER Refresh) trace; the other filters are enabled[^9]. The Cisco CallManager trace filter Enable SIP Stack Trace activates trace of the SIP stack and is enabled by default[^45]. The Cisco CallManager trace filter Enable SIP Call Processing Trace activates trace for SIP call processing[^39]. Enable SIP Keep Alive (REGISTER Refresh) Trace activates trace of SIP REGISTER refresh keepalives and Cisco warns it generates a large amount of trace data[^41]. The Cisco CallManager SDL configuration trace filter settings include Enable all Layer 1 traces, Enable all Layer 2 traces, Enable Layer 2 interface trace, Enable all Layer 3 traces and Enable all call control traces[^37]. The Cisco CallManager SDL configuration trace characteristics include Enable SDL link states trace, Enable low-level SDL trace, Enable SDL TCP event trace and Disable pretty print of SDL trace[^34]. Troubleshooting Trace Settings backs up the original configuration and applies predetermined troubleshooting trace settings; leaving it enabled for a long time increases trace file size and may affect service performance[^50]. Reset Troubleshooting Traces restores the original trace settings for the services on the chosen node[^25]. ## File storage and rollover Trace Output Settings expose Maximum No. of Files (total trace files for a service) and Maximum File Size in megabytes; the release 15 guide says their defaults vary by service and does not print CallManager values[^19]. When the last trace file in the sequence is full, trace data begins writing over the first file, so the oldest trace data is lost[^26]. Changing Maximum No. of Files or Maximum File Size causes the system to delete all service log files except the current file[^20]. WarmTransfer's reading of the sources is that before increasing CallManager trace file count or size during an incident, the existing SDL files should be collected first, because the change deletes all but the current file[^5]. We infer that because SDL files roll over in a fixed-size ring, the time window an SDL collection can cover depends on call volume and the configured file count and size, so traces for a past incident may already be overwritten[^6]. Cisco CallManager SDL trace files live under activelog cm/trace/ccm/sdl/ and can be listed with file list activelog cm/trace/ccm/sdl/SDL* detail[^35]. In CUCM 14 Cisco CallManager SDL files match activelog /cm/trace/ccm/sdl/SDL00*_100*.txt and Cisco CTIManager SDL files match activelog /cm/trace/cti/sdl/SDL*_200_*.txt[^3]. This is inferred: the middle numeric field of an SDL filename (100 versus 200) distinguishes the Cisco CallManager process from the Cisco CTIManager process[^22]. The Cisco CallManager service also writes call logs at activelog /cm/trace/ccm/calllogs/calllogs*.txt, separate from the SDL files[^2]. CallManager trace files pulled from the CLI are normally.gz files; a.gzo file is one that was still open for writing at download time and may not open cleanly[^12]. For a.gzo file that will not open, Cisco suggests the CLI file view command or zcat on a Linux system[^13]. The CLI reference warns not to use file view on binary files because it can corrupt the terminal session[^11]. The CLI command file get {activelog|inactivelog|install} file-spec [reltime|abstime] [match regex] [recurs] [compress] sends matching logs to another system over SFTP after prompting for host, username and password[^4]. ## Collection with RTMT Trace and Log Central, an option in Cisco Unified RTMT, is the documented tool to collect, view and zip service traces and other log files[^46]. In RTMT, SDL traces are collected via System > Tools > Trace & Log Central and double-clicking Collect Files, which opens the Trace Collection wizard[^27]. Cisco's collection procedure selects Cisco CallManager and Cisco CTIManager on all servers, plus Event Viewer-Application Log and Event Viewer-System Log[^30]. The RTMT Collect Files wizard accepts either an Absolute Range (start and end date and time) or a Relative Range (minutes, hours, days, weeks or months before now)[^31]. In Collect Files, choosing the Zip File radio button creates a zip file of the collected traces[^32]. Collect Files offers a Delete Collected Log Files from the server check box that removes the collected files from the node[^28]. The default Collect Files download location is \\, changeable with Browse[^29]. RTMT writes TraceCollectionResult*.xml files that state which files were successfully downloaded from each server[^47]. RTMT can schedule up to 6 concurrent trace collections to an SFTP server; FTP is no longer supported from release 14SU3 onward[^33]. RTMT Remote Browse views or downloads traces directly on a node and allows a maximum of 5 concurrently open files[^24]. RTMT View Real Time Data shows live trace data for up to 10 services with a limit of 3 concurrent sessions on a single node[^23]. When trace compression is enabled, RTMT real-time trace data can appear bursty and event detection can be delayed because of data buffering[^7]. ## Reading trace line formats Cisco's sample CallManager trace lines are pipe-delimited, beginning with a numeric sequence field, then a time-of-day timestamp with milliseconds, then a tag such as AppInfo[^17]. Inbound SIP messages appear in CallManager traces on a SIPTcp - wait_SdlReadRsp line of the form Incoming SIP TCP message from on port index with bytes, followed by the SIP message[^40]. Outbound SIP messages appear in CallManager traces on a SIPTcp - wait_SdlSPISignal line of the form Outgoing SIP TCP message to on port index [^44]. When an inbound SIP message exceeds SIP Max Incoming Message Size, the CallManager trace shows a SIPTcp line stating that it is ignoring a large message, the byte limit, and that it is resetting the connection[^42]. SIP Max Incoming Message Size defaulted to 5000 bytes in CUCM 8.6 and earlier and 11000 bytes from 9.x; clusters upgraded from 8.x or earlier keep 5000[^43]. ## See also See also [Unified CM service parameters that change transfer behaviour](https://warmtransfer.net/knowledge/cucm-service-parameters-for-transfer). See also [Unified CM SIP trunks and security profiles](https://warmtransfer.net/knowledge/cucm-sip-trunks). See also [Unified CM release trains and lifecycle dates](https://warmtransfer.net/knowledge/cucm-versions-lifecycle). ## Applicability The deployment model is not covered by the sources below. ## What remains uncertain The default numeric values for Maximum No. of Files and Maximum File Size for the Cisco CallManager service in release 15 are not covered by the sources below. ## Sources [^1]: Trace settings for a service can be applied to every server in the cluster by checking Apply to All Nodes, with the Trace On check box enabling tracing. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Configure Trace Parameters procedure. Checked 2026-09-22. [^2]: The Cisco CallManager service also writes call logs at activelog /cm/trace/ccm/calllogs/calllogs*.txt, separate from the SDL files. Source: [Troubleshoot Trace Locations in CLI for CUCM 14](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/220309-troubleshoot-trace-locations-in-cli-for.html), Trace locations table, row Cisco CallManager. Checked 2026-09-22. [^3]: In CUCM 14 Cisco CallManager SDL files match activelog /cm/trace/ccm/sdl/SDL00*_100*.txt and Cisco CTIManager SDL files match activelog /cm/trace/cti/sdl/SDL*_200_*.txt. Source: [Troubleshoot Trace Locations in CLI for CUCM 14](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/220309-troubleshoot-trace-locations-in-cli-for.html), Trace locations table, rows Cisco CallManager and Cisco CTIManager. Checked 2026-09-22. [^4]: The CLI command file get {activelog|inactivelog|install} file-spec [reltime|abstime] [match regex] [recurs] [compress] sends matching logs to another system over SFTP after prompting for host, username and password. Source: [Command Line Interface Reference Guide for Cisco Unified Communications Solutions, Release 15 and SUs - File Commands](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/cli_ref/15/cucm_b_cli_reference_guide_release_15/cucm_b_cli_reference_guide_release_1401_chapter_011.html), File Commands > file get. Checked 2026-09-22. [^5]: Before increasing CallManager trace file count or size during an incident, the existing SDL files should be collected first, because the change deletes all but the current file (inferred). Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Trace Output Settings, Caution (reasoned from). Checked 2026-09-22. [^6]: Because SDL files roll over in a fixed-size ring, the time window an SDL collection can cover depends on call volume and the configured file count and size, so traces for a past incident may already be overwritten (inferred). Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Trace Output Settings (reasoned from rollover sentence). Checked 2026-09-22. [^7]: When trace compression is enabled, RTMT real-time trace data can appear bursty and event detection can be delayed because of data buffering. Source: [Cisco Unified Real-Time Monitoring Tool Administration Guide, Release 12.5(1) - Traces and Logs](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/service/12_5_1/rtmt/cucm_b_cisco-unified-rtmt-administration-1251/cucm_mp_t52b2b22_00_traces-and-logs.html), Real-Time Trace > View Real-Time Data; Monitor User Event. Checked 2026-09-22. [^8]: Enabling the Trace Compression enterprise parameter adds CPU cycles and can reduce overall call throughput by as much as 10 percent. Source: [Cisco Unified Real-Time Monitoring Tool Administration Guide, Release 15 and SUs - Traces and Logs](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/service/15/rtmt/cucm_b_cisco-unified-rtmt-administration-15/cucm_b_cisco-unified-rtmt-administration-1251su2_chapter_01000.html), Trace and Log Central > Log Compression. Checked 2026-09-22. [^9]: In the default CallManager trace configuration the filters left disabled are Miscellaneous, SoftKey, Route or Hunt List, All GateWay, SCCP Keep Alive, SpeedDial and SIP Keep Alive (REGISTER Refresh) trace; the other filters are enabled. Source: [Collect Trace Data from a CUCM Cluster](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/200787-How-to-Collect-Traces-for-CUCM-9-x-10-x.html), Configure > Set CallManager trace levels (trace filter defaults). Checked 2026-09-22. [^10]: In CUCM 9.x and later the default Debug Trace Level for the Cisco CallManager service is Detailed. Source: [Collect Trace Data from a CUCM Cluster](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/200787-How-to-Collect-Traces-for-CUCM-9-x-10-x.html), Configure > Set CallManager trace levels (default settings). Checked 2026-09-22. [^11]: The CLI reference warns not to use file view on binary files because it can corrupt the terminal session. Source: [Command Line Interface Reference Guide for Cisco Unified Communications Solutions, Release 15 and SUs - File Commands](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/cli_ref/15/cucm_b_cli_reference_guide_release_15/cucm_b_cli_reference_guide_release_1401_chapter_011.html), File Commands > file view. Checked 2026-09-22. [^12]: CallManager trace files pulled from the CLI are normally .gz files; a .gzo file is one that was still open for writing at download time and may not open cleanly. Source: [Collect CCM Traces Through CLI](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/200953-Collect-CCM-Traces-Through-CLI.html), Collect traces through CLI (note on .gzo files). Checked 2026-09-22. [^13]: For a .gzo file that will not open, Cisco suggests the CLI file view command or zcat on a Linux system. Source: [Collect CCM Traces Through CLI](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/200953-Collect-CCM-Traces-Through-CLI.html), Collect traces through CLI (note on .gzo files). Checked 2026-09-22. [^14]: The Detailed trace level traces all Arbitrary conditions plus detailed debugging information. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Debug Trace Level Settings > Debug Trace Levels for Services, row Detailed. Checked 2026-09-22. [^15]: The Error trace level traces alarm conditions and events and is used for traces generated in an abnormal path. Source: [Administration Guide for Cisco Unified Communications Manager, Release 14 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/14SU2/adminGd/cucm_b_administration-guide-14su2/cucm_b_test-adminguide_chapter_011000.html), Debug Trace Level Settings > Debug Trace Levels for Services, row Error. Checked 2026-09-22. [^16]: CUCM service debug trace levels are cumulative in the order Error, Special, State Transition, Significant, Entry/Exit, Arbitrary, Detailed, each level tracing everything the previous level does plus more. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Debug Trace Level Settings > Debug Trace Levels for Services. Checked 2026-09-22. [^17]: Cisco's sample CallManager trace lines are pipe-delimited, beginning with a numeric sequence field, then a time-of-day timestamp with milliseconds, then a tag such as AppInfo. Source: [Native Call Queueing Enhancement in CUCM 11.5](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/210537-Native-Call-Queueing-Enhancement-in-CUCM.html), Log Analysis (sample traces). Checked 2026-09-22. [^18]: From Unified Communications Manager 8.0 onward the log compression feature compresses certain log files in gzip format, the file currently being written carries a .gzo extension, and CLI view and tail commands uncompress automatically. Source: [Cisco Unified Real-Time Monitoring Tool Administration Guide, Release 15 and SUs - Traces and Logs](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/service/15/rtmt/cucm_b_cisco-unified-rtmt-administration-15/cucm_b_cisco-unified-rtmt-administration-1251su2_chapter_01000.html), Trace and Log Central > Log Compression. Checked 2026-09-22. [^19]: Trace Output Settings expose Maximum No. of Files (total trace files for a service) and Maximum File Size in megabytes; the release 15 guide says their defaults vary by service and does not print CallManager values. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Trace Output Settings table. Checked 2026-09-22. [^20]: Changing Maximum No. of Files or Maximum File Size causes the system to delete all service log files except the current file. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Trace Output Settings, Caution. Checked 2026-09-22. [^21]: Cisco warns that enabling trace decreases system performance and should be done only for troubleshooting. Source: [Administration Guide for Cisco Unified Communications Manager, Release 14 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/14SU2/adminGd/cucm_b_administration-guide-14su2/cucm_b_test-adminguide_chapter_011000.html), Trace > Trace Configuration (note). Checked 2026-09-22. [^22]: The middle numeric field of an SDL filename (100 versus 200) distinguishes the Cisco CallManager process from the Cisco CTIManager process (inferred). Source: [Troubleshoot Trace Locations in CLI for CUCM 14](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/220309-troubleshoot-trace-locations-in-cli-for.html), Trace locations table, rows Cisco CallManager and Cisco CTIManager (reasoned from). Checked 2026-09-22. [^23]: RTMT View Real Time Data shows live trace data for up to ten services with a limit of three concurrent sessions on a single node. Source: [Cisco Unified Real-Time Monitoring Tool Administration Guide, Release 15 and SUs - Traces and Logs](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/service/15/rtmt/cucm_b_cisco-unified-rtmt-administration-15/cucm_b_cisco-unified-rtmt-administration-1251su2_chapter_01000.html), Trace and Log Central > Real-Time Trace > View Real-Time Data. Checked 2026-09-22. [^24]: RTMT Remote Browse views or downloads traces directly on a node and allows a maximum of five concurrently open files. Source: [Cisco Unified Real-Time Monitoring Tool Administration Guide, Release 15 and SUs - Traces and Logs](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/service/15/rtmt/cucm_b_cisco-unified-rtmt-administration-15/cucm_b_cisco-unified-rtmt-administration-1251su2_chapter_01000.html), Trace and Log Central > Display Trace Files Using Remote Browse. Checked 2026-09-22. [^25]: Reset Troubleshooting Traces restores the original trace settings for the services on the chosen node. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Trace Setting Troubleshooting. Checked 2026-09-22. [^26]: When the last trace file in the sequence is full, trace data begins writing over the first file, so the oldest trace data is lost. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Trace Output Settings, Maximum No. of Files row. Checked 2026-09-22. [^27]: In RTMT, SDL traces are collected via System > Tools > Trace & Log Central and double-clicking Collect Files, which opens the Trace Collection wizard. Source: [Collect Trace Data from a CUCM Cluster](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/200787-How-to-Collect-Traces-for-CUCM-9-x-10-x.html), Collect traces with RTMT. Checked 2026-09-22. [^28]: Collect Files offers a Delete Collected Log Files from the server check box that removes the collected files from the node. Source: [Cisco Unified Real-Time Monitoring Tool Administration Guide, Release 15 and SUs - Traces and Logs](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/service/15/rtmt/cucm_b_cisco-unified-rtmt-administration-15/cucm_b_cisco-unified-rtmt-administration-1251su2_chapter_01000.html), Trace and Log Central > Collect Files. Checked 2026-09-22. [^29]: The default Collect Files download location is \\, changeable with Browse. Source: [Cisco Unified Real-Time Monitoring Tool Administration Guide, Release 15 and SUs - Traces and Logs](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/service/15/rtmt/cucm_b_cisco-unified-rtmt-administration-15/cucm_b_cisco-unified-rtmt-administration-1251su2_chapter_01000.html), Trace and Log Central > Collect Files. Checked 2026-09-22. [^30]: Cisco's collection procedure selects Cisco CallManager and Cisco CTIManager on all servers, plus Event Viewer-Application Log and Event Viewer-System Log. Source: [Collect Trace Data from a CUCM Cluster](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/200787-How-to-Collect-Traces-for-CUCM-9-x-10-x.html), Collect traces with RTMT (service check boxes). Checked 2026-09-22. [^31]: The RTMT Collect Files wizard accepts either an Absolute Range (start and end date and time) or a Relative Range (minutes, hours, days, weeks or months before now). Source: [Cisco Unified Real-Time Monitoring Tool Administration Guide, Release 15 and SUs - Traces and Logs](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/service/15/rtmt/cucm_b_cisco-unified-rtmt-administration-15/cucm_b_cisco-unified-rtmt-administration-1251su2_chapter_01000.html), Trace and Log Central > Collect Files. Checked 2026-09-22. [^32]: In Collect Files, choosing the Zip File radio button creates a zip file of the collected traces. Source: [Cisco Unified Real-Time Monitoring Tool Administration Guide, Release 15 and SUs - Traces and Logs](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/service/15/rtmt/cucm_b_cisco-unified-rtmt-administration-15/cucm_b_cisco-unified-rtmt-administration-1251su2_chapter_01000.html), Trace and Log Central > Collect Files. Checked 2026-09-22. [^33]: RTMT can schedule up to six concurrent trace collections to an SFTP server; FTP is no longer supported from release 14SU3 onward. Source: [Cisco Unified Real-Time Monitoring Tool Administration Guide, Release 15 and SUs - Traces and Logs](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/service/15/rtmt/cucm_b_cisco-unified-rtmt-administration-15/cucm_b_cisco-unified-rtmt-administration-1251su2_chapter_01000.html), Trace and Log Central > Schedule Trace Collection. Checked 2026-09-22. [^34]: The Cisco CallManager SDL configuration trace characteristics include Enable SDL link states trace, Enable low-level SDL trace, Enable SDL TCP event trace and Disable pretty print of SDL trace. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Cisco CallManager SDL Configuration Trace Characteristics. Checked 2026-09-22. [^35]: Cisco CallManager SDL trace files live under activelog cm/trace/ccm/sdl/ and can be listed with file list activelog cm/trace/ccm/sdl/SDL* detail. Source: [Collect CCM Traces Through CLI](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/200953-Collect-CCM-Traces-Through-CLI.html), Collect traces through CLI > file list example. Checked 2026-09-22. [^36]: In CUCM release 15, SDL stands for Signaling Distribution Layer trace and is supported for the Cisco CallManager and Cisco CTIManager services on Unified Communications Manager only. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Trace > What is Trace; Cisco CallManager SDL Trace Fields. Checked 2026-09-22. [^37]: The Cisco CallManager SDL configuration trace filter settings include Enable all Layer 1 traces, Enable all Layer 2 traces, Enable Layer 2 interface trace, Enable all Layer 3 traces and Enable all call control traces. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Cisco CallManager SDL Configuration Trace Filter Settings. Checked 2026-09-22. [^38]: From CUCM 9.x onward, Cisco CallManager traces are written as a single interleaved set of SDL* files rather than separate SDL* and ccm* file sets. Source: [Collect Trace Data from a CUCM Cluster](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/200787-How-to-Collect-Traces-for-CUCM-9-x-10-x.html), Background Information (9.x trace note). Checked 2026-09-22. [^39]: The Cisco CallManager trace filter Enable SIP Call Processing Trace activates trace for SIP call processing. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Cisco CallManager SDI Trace Fields, row Enable SIP Call Processing Trace. Checked 2026-09-22. [^40]: Inbound SIP messages appear in CallManager traces on a SIPTcp - wait_SdlReadRsp line of the form Incoming SIP TCP message from on port index with bytes, followed by the SIP message. Source: [Native Call Queueing Enhancement in CUCM 11.5](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/210537-Native-Call-Queueing-Enhancement-in-CUCM.html), Log Analysis (sample traces). Checked 2026-09-22. [^41]: Enable SIP Keep Alive (REGISTER Refresh) Trace activates trace of SIP REGISTER refresh keepalives and Cisco warns it generates a large amount of trace data. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Cisco CallManager SDI Trace Fields, row Enable SIP Keep Alive (REGISTER Refresh) Trace. Checked 2026-09-22. [^42]: When an inbound SIP message exceeds SIP Max Incoming Message Size, the CallManager trace shows SIPTcp - Ignoring large message ... Only allow up to bytes. Resetting connection. Source: [Troubleshoot Most Common Issues for Business to Business Calls Through Expressway](https://www.cisco.com/c/en/us/support/docs/unified-communications/expressway/213863-troubleshoot-most-common-issues-for-busi.html), Error //SIP/SIPTcp/wait_SdlReadRsp: Ignoring large message. Checked 2026-09-22. [^43]: SIP Max Incoming Message Size defaulted to 5000 bytes in CUCM 8.6 and earlier and 11000 bytes from 9.x; clusters upgraded from 8.x or earlier keep 5000. Source: [Troubleshoot Most Common Issues for Business to Business Calls Through Expressway](https://www.cisco.com/c/en/us/support/docs/unified-communications/expressway/213863-troubleshoot-most-common-issues-for-busi.html), Error //SIP/SIPTcp/wait_SdlReadRsp: Ignoring large message > Solution. Checked 2026-09-22. [^44]: Outbound SIP messages appear in CallManager traces on a SIPTcp - wait_SdlSPISignal line of the form Outgoing SIP TCP message to on port index . Source: [Native Call Queueing Enhancement in CUCM 11.5](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/210537-Native-Call-Queueing-Enhancement-in-CUCM.html), Log Analysis (sample traces). Checked 2026-09-22. [^45]: The Cisco CallManager trace filter Enable SIP Stack Trace activates trace of the SIP stack and is enabled by default. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Cisco CallManager SDI Trace Fields, row Enable SIP Stack Trace. Checked 2026-09-22. [^46]: Trace and Log Central, an option in Cisco Unified RTMT, is the documented tool to collect, view and zip service traces and other log files. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Trace Collection. Checked 2026-09-22. [^47]: RTMT writes TraceCollectionResult*.xml files that state which files were successfully downloaded from each server. Source: [Collect Trace Data from a CUCM Cluster](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/200787-How-to-Collect-Traces-for-CUCM-9-x-10-x.html), Verify collected files. Checked 2026-09-22. [^48]: CallManager trace settings are configured in Cisco Unified Serviceability under Trace > Configuration by selecting the server, the CM Services service group and the Cisco CallManager service. Source: [Collect Trace Data from a CUCM Cluster](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/200787-How-to-Collect-Traces-for-CUCM-9-x-10-x.html), Configure > Set CallManager trace levels. Checked 2026-09-22. [^49]: Cisco Unified Serviceability supports three trace kinds: SDI (System Diagnostic Interface) trace, SDL trace, and Log4J trace for Java applications. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Trace > What is Trace. Checked 2026-09-22. [^50]: Troubleshooting Trace Settings backs up the original configuration and applies predetermined troubleshooting trace settings; leaving it enabled for a long time increases trace file size and may affect service performance. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Trace](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_b_test-adminguide_chapter_011000.html), Trace Setting Troubleshooting. Checked 2026-09-22. [^51]: In Cisco Unified CallManager 4.2(1) SDL trace covered Cisco CallManager, Cisco CTIManager and Cisco TFTP and SDI and SDL logs could be written in XML format; this no longer describes current releases, where SDL applies to CallManager and CTIManager only. Source: [Cisco Unified CallManager Serviceability System Guide, Release 4.2(1) - Trace](https://www.cisco.com/en/US/docs/voice_ip_comm/cucm/service/4_2_1/ccmsrvs/sstrace.html), Trace > SDL Trace; Trace Configuration (XML formatted output). Checked 2026-09-22.