How SIP Trunking works in CISCO Business Edition 3000

In the Cisco Business Edition 3000, the SIP trunk serves as a connection to the SIP service provider network for PSTN connectivity. To interact with the SIP trunk connection, the Cisco Business Edition 3000 requires SBE (Session Border Elements) to provide security, topology hiding, and ALG (Application Level Gateway) functionalities.

To achieve SIP trunking, use the following operations:

• Provision Cisco Business Edition 3000 to interact with the SBE. You can achieve this by the installation of Connection Packs, and by adding the SIP trunk connection through Cisco Business Edition 3000 Administrative Interface.
  
• Provision SBE to interact with Cisco Business Edition 3000. You can achieve this using the configurations provided by the service provider.
  
• Provision SBE to interact with the service provider. You can manage this using the service provider.
  

The following list describes the different types of SIP trunk connections that are used with Cisco Business Edition 3000:

• Standard Cisco SIP trunk connection - SIP trunk is connected to the service provider through the Cisco Unified Border Element (CUBE) on Cisco ISR8xx Series (Integrated Services Router). The parameters on the Cisco Business Edition 3000 for the SIP trunk connection are preconfigured to support general SIP trunk functionalities.
  

Note Cisco TAC provides support for Cisco Unified Border Element (CUBE) only. For other sessions, contact your service providers.

• Service Provider SIP trunk connection - SIP trunk is connected to the service provider through other SBEs. The parameters of the Cisco Business Edition 3000 SIP trunk connection is preconfigured based on the inter-operational tests with specific service provider. The service provider for provisioning is available after the installation of the SIP trunk connection pack that is customized for the service provider.
  

If the Cisco Business Edition 3000 deployment requires SIP trunk connection in your site, deploy an SBE in the site to route PSTN calls. This SIP trunk connection can also be used to route the PSTN calls from other sites.

Cisco Business Edition 3000 also supports multiple SIP trunks to the service provider through a single or multiple session border elements.

Note If a remote site needs to deploy a SIP trunk connection to its local SIP service provider, deploy a session border element on the remote site, rather than using the SIP trunk on the central site. The SIP trunk configured on the central site can also be used.

To add, edit, or delete SIP trunk connections, sign in to the Cisco Business Edition 3000 Administrative Interface (Connections > PSTN Connections).

Additionally, you must bind a SIP trunk/SBE with a site using the service provider IP address specified on the SIP trunk connection and provision the subnet on the site (Connections > Sites > General tab).

Provisioning scope for SIP trunk with Cisco Business Edition 3000

Note SIP Trunk is another PSTN connection type along with T1/E1 PRI, T1 CAS, and FXO connections.

Based on the requirement of PSTN connections for Cisco Business Edition 3000, provisioning is performed for routing of PSTN calls using the gateway on Connections > Sites > Add Site > PSTN Access.

Limitations of SIP Trunking

Cisco Business Edition 3000 does not support the following features on SIP trunk to service providers:

• Digest authentication
  
• QSIG
  
• TLS
  
• IME
  
• MLPP
  
• IPV6
  
• MTP
  
• Raw DTMF
  
• RSVP
  

Cisco Business Edition 3000 does not support the following functionalities on SIP trunk:

• pTime - This media-based parameter cannot be configured on Cisco Business Edition 3000. However, a fixed value will be used.
  
• DTMF - The PSTN calls with SIP trunk connection encountering DTMF incompatibility requires an MTP to normalize the DTMF. As Cisco Business Edition 3000 does not support MTP, the call fails.
  
• Early media on 180 - For SIP trunk connections, Cisco Business Edition 3000 signals calling phone to play local ringback as it does not receive SDP in the 180 response. However, the system receives as SDP in the 183 response.