Asterisk documentation warns that if the TCP switch is enabled, a large message switched to TCP fails when no TCP transport is configured or the remote side is not listening on TCP.
Checked 2026-10-02
If your system has not been configured with a TCP transport this will fail.
- Vendor
- Sangoma
- Product
- Asterisk
- Subsystem
- res_pjsip
- Deployment
- on-premises
- Region
- not restricted
- Release range
- current as of 2026-10-02
- Checked
- 2026-10-02
Sources
- PJSIP Transport Selection - Asterisk Documentation — Sangoma / Asterisk project · tier 2 current vendor documentation · Changeover to TCP when sending via UDP
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting failed calls caused by large SIP messages over UDP: source note sip-fragmentation-troubleshooting-asterisk-switch-needs-tcp. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-fragmentation-troubleshooting-asterisk-switch-needs-tcp
BibTeX
@misc{warmtransfer-claim-sip-fragmentation-troubleshooting-asterisk-switch-needs-tcp,
title = {Troubleshooting failed calls caused by large SIP messages over UDP: source note sip-fragmentation-troubleshooting-asterisk-switch-needs-tcp},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-fragmentation-troubleshooting-asterisk-switch-needs-tcp},
note = {Source note sip-fragmentation-troubleshooting-asterisk-switch-needs-tcp, checked 2026-10-02}
}