Feature Configuration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Configure Call Throttling

Publisher

Cisco Systems

URL

https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/cucm_b_feature-configuration-guide-for-15/cucm_m_configure-call-throttling.html

Published

2026-09-16

Updated

unknown

Accessed

2026-10-02

HTTP status

200

License

Cisco copyrighted documentation; no-redistribution; short excerpts and locators only

Source notes citing this source

• Unified CM also supports memory-based throttling, turned on by setting the Enable Memory Throttling service parameter to True. in context
• Unified CM stops throttling calls and exits the Code Yellow state on its own once delay to dial tone is back within the call throttling service parameter guidelines. in context
• Cisco lists heavy call activity, low CPU availability, routing loops, disk I/O limitations and disk fragmentation as conditions that can delay dial tone and trigger call throttling. in context
• Unified CM call throttling automatically throttles or denies new call attempts when conditions would cause excessive delay between going off hook and receiving dial tone; in that state the system is in Code Yellow. in context
• Cisco recommends not modifying the call throttling service parameters unless advised to do so by customer support. in context
• Call throttling parameters, including Code Yellow Entry Latency and Code Yellow Duration, are under System > Service Parameters, Cisco CallManager service, Advanced, in the Call Throttling section. in context
• When call throttling is active, a user attempting a new call receives a reorder tone and, depending on phone model, may also see a prompt on the phone display. in context

Cite this source record

APA

WarmTransfer. (2026, September 16). Feature Configuration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Configure Call Throttling. WarmTransfer. https://warmtransfer.net/knowledge/sources/cisco-cucm-fcg-15-call-throttling

BibTeX

@misc{warmtransfer-cisco-cucm-fcg-15-call-throttling,
  title  = {Feature Configuration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Configure Call Throttling},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/sources/cisco-cucm-fcg-15-call-throttling},
  note   = {Cisco Systems, accessed 2026-10-02}
}