Anonymous SIP Calls

This document walks you through on how to implement anonymous SIP calls in a Cisco Voice Gateway (e.g 28xx/38xx, 29xx/39xx).

1. Enable privacy at the header level in the SIP message. This setting affects all calls (applied globally).

voice service voip sip privacy header

2. This dial-peer configuration prevents the calling-party number from being shown. […]

Cisco SPA 112 ATA on CUCM

One of Cisco employees shared a document on how to configure Cisco SPA 112 ATA on CUCM. The document walk you through the setup and common issues encountered with solutions. My challenge was I had difficulty in registering Cisco SPA 112 ATA to CUCM 10.5.

I took a packet capture on the registration process […]

Acme Packet Duplicate SIP Attributes

Issue: Acme Packet SBC sending duplicate SIP attributes which causes MS Lync 2013 to drop the call. However, Cisco CUBE and Cisco Voice Gateways have no problem in processing duplicate attributes.

v=0 o=- 1385372910 1385372910 IN IP4 192.168.1.1 s=- c=IN IP4 192.168.1.1 t=0 0 m=audio 10178 RTP/AVP 0 8 101 a=rtpmap:0 PCMU/8000 a=rtpmap:8 PCMA/8000 a=rtpmap:101 […]