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Deploying and Troubleshooting SIP Trunks with Cisco Unified Border Element (CUBE) Enterprise and CUCMC Lab

March 2020


Innovations in collaboration services have delivered significant improvements in employee productivity and enterprises are widely deploying IP based Unified Communications, both for internal calling within the enterprise and external PSTN access. This has resulted in significant migration from TDM based circuits, by both enterprises and telephony service providers, to IP-based trunks for Unified Communication. At the heart of IP-based telephony trunks lies the Session Initiation Protocol (SIP), which is an industry standard communications protocol based on RFC3261, and is widely used for controlling multimedia communication sessions and applications such as voice, video, unified messaging, voicemail, and conferencing.

These SIP trunks terminate on a session Border Controller (SBC) at the enterprise that serves as a demarcation point between the enterprise and the service provider IP networks, similar to how firewalls separate two data networks. The Cisco Unified Border Element (CUBE) Enterprise is Cisco’s SBC offering and it enables rich multimedia communications for enterprises by providing:

Session Control – Call Admission Control, Trunk Routing, QoS, Statistics, Billing, Redundancy, Scalability, Voice Quality Monitoring.

Security – Encryption, Authentication, Registration, SIP Protection, Voice Policy, Toll Fraud Prevention, Telephony Denial of Service (TDoS) Attack protection. 

Interworking – Various SIP and H323 Stack Interoperability, SIP Normalization, DTMF, Transcoding, Transrating, Codec Filtering. 

Demarcation – Fault Isolation, Topology and Address Hiding, L5/L7 Protocol Demarcation, Network Border.

CUBE enables substantial cost savings by providing essential capabilities that ensure interoperability, security and service assurance when carrying IP traffic via SIP trunking across different enterprises and service provider networks. It is a Back-to-Back User Agent (B2BUA) and is part of the IOS infrastructure on ISR G2/800 series platforms, IOS-XE for the ASR1K, ISR4K series and CUBE on CSR1000v (virtual CUBE – vCUBE).

As the use of SIP continues to expand in the industry, Cisco continues to provide capabilities in Cisco IOS/IOS-XE Software products and features to enable rich communications methods along with significant cost savings by leveraging existing infrastructure and flexibility for migration.


The objective for this lab is to provide hands-on training in deploying SIP Trunking in an enterprise voice network based on Cisco Unified Communications Manager (CUCM) and Cisco Unified Border Element (CUBE) Enterprise edition.

This lab provides detailed explanation, verification procedures, best practices, and is designed to maximize learning by providing practical hands-on training. It will also introduce newer features that existing enterprises can deploy to enhance their collaboration experience.


Module 1 – Connecting Enterprise UC Network to ITSP’s SIP Trunk
Module 2 – Basic SIP Profiles and Debug Categorization
Module 3 – Configuring Media Transcoding
Module 4 – Configuring Call Admission Control
Module 5 – Configurable SIP Error codes
Module 6 – Destination Dial-peer Group and Inbound SIP Profiles
Module 7 – SIP Profile Rule Tagging
Module 8 – Multiple E164 Pattern matching under the same dial-peer
Module 9 – Destination Server Group
Module 10 – CUBE + SIP SRST Co-location and Multi-tenancy
Module 11 – Call Progress Analysis Over IP-IP
Appendix A. Troubleshooting Outbound PSTN Call Failure from Module 1

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