On Cisco IOS voice gateways and CUBE, the dial-peer command voice-class sip transport switch udp tcp switches a SIP request from UDP to TCP when the request size exceeds the MTU size.
Checked 2026-10-02
- Vendor
- Cisco
- Product
- Cisco Unified Border Element
- Subsystem
- SIP transport
- Deployment
- on-premises
- Region
- not restricted
- Release range
- 12.3(8)T and later
- Checked
- 2026-10-02
Sources
- Cisco IOS Voice Command Reference - T through Z - voice-class sip error-code-override through vxml version 2.0 — Cisco Systems · tier 2 current vendor documentation · voice-class sip transport switch: Syntax Description
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting failed calls caused by large SIP messages over UDP: source note sip-fragmentation-troubleshooting-cube-vc-transport-switch. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-fragmentation-troubleshooting-cube-vc-transport-switch
BibTeX
@misc{warmtransfer-claim-sip-fragmentation-troubleshooting-cube-vc-transport-switch,
title = {Troubleshooting failed calls caused by large SIP messages over UDP: source note sip-fragmentation-troubleshooting-cube-vc-transport-switch},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-fragmentation-troubleshooting-cube-vc-transport-switch},
note = {Source note sip-fragmentation-troubleshooting-cube-vc-transport-switch, checked 2026-10-02}
}