Jointly-Provided Features, Session Timer

Chapter 2 SIP Protocol Subscriber Features

Jointly-Provided Features

In addition to the Softswitch-based and phone-based features, Release 4.4 also offers jointly-provided features. These are features provided jointly by the phone and by the Cisco BTS 10200. To use these features, you must provision both the phone and the Cisco BTS 10200.

These features include:

•Session Timer

•Reliable Provisional Responses

•Text-GUI Features

•Call Transfer (Blind and Attended)

•Distinctive Ringing

•Distinctive Ringing for Centrex DID Calls

Session Timer

This SIP extension allows for a periodic refresh of SIP sessions through a SIP re-INVITE or UPDATE request. The refresh allows the Cisco BTS 10200 SIP interface to determine if a SIP session is still active. If the session is inactive, possibly because the session did not end normally, the Cisco BTS 10200 sends a SIP BYE request and cleans up resources dedicated to the session. Stateful SIP proxies and the remote SIP endpoint handling the BYE request can clean up resources dedicated to this session as well.

Cisco BTS 10200 support for this feature follows the specifications described in the IETF draft draft-ietf-sip-session-timer-08. Session durations are configured within a range of 30 minutes to 2 hours. Cisco BTS 10200 does not allow for negotiating a session less than 15 minutes. Cisco BTS 10200 SIP interface does not impose the session timer feature be required on the remote SIP endpoint. This feature does not require the session timer capability on the remote SIP endpoint.

In the unlikely event of a call agent redundancy failover, the session timer is deactivated. This may result in eventual session expiration and call release.

This feature can be enabled or disabled for all SIP subscribers; the feature is disabled by default. This feature is enabled by provisioning the SUB-SESSION-TIMER-ALLOWED entry in the CA-CONFIG table.

If the feature is enabled for a SIP subscriber, Cisco BTS 10200 (as UAC) adds, to the initial INVITE message, a supported header with a ‘timer’ value, as well as a Session-Expires header with the Refresher parameter set to ‘Uac’. Whenever the SIP call is sent from a Cisco BTS 10200 SIP subscriber,

Cisco BTS 10200 specifies itself to be the refresher. If Session Timer is not supported on the remote end, the value sent in the Session-Expires header is set for the session duration. A periodic refresh request is sent at half of the negotiated Session-Expires value.

When this feature is enabled for the SIP subscriber and an initial INVITE is received by the

Cisco BTS 10200 with a Supported header with ‘timer’ value and a Session-Expires header, it sends a 200 class response with a Require header specifying ‘timer,’ and a Session-Expires header and refresher parameter. The Session-Expires header contains a session duration and refresher value set to whatever was received in the initial INVITE. If refresher parameter is not received in the initial INVITE, Cisco BTS 10200 sets it to ‘Uas’ indicating Cisco BTS 10200 is the refresher. Cisco BTS 10200 sends periodic refresh request at half the negotiated session duration.

Cisco BTS 10200 Softswitch SIP Protocol User Guide

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BTS 10200 specifications

Cisco Systems BTS 10200 is a robust platform designed to meet the demands of modern telecommunications. This session border controller (SBC) facilitates the management of voice over IP (VoIP) traffic, enabling secure and efficient communication across diverse networks. The BTS 10200 plays a critical role in integrating voice and data services while ensuring high-quality user experiences and regulatory compliance.

One of the standout features of the BTS 10200 is its ability to support a wide range of protocols, making it highly versatile. It is compatible with both legacy systems and modern IP-based solutions, ensuring seamless interoperability. This adaptability allows service providers to migrate to next-generation networks without disrupting existing services.

The BTS 10200 is built upon a highly scalable architecture, allowing it to handle large volumes of traffic. This scalability is crucial for service providers as they expand their networks to accommodate more users and services. The platform supports hundreds of thousands of simultaneous sessions, which is essential for large-scale deployments such as in mobile and fixed-line networks.

Security is a paramount feature of the BTS 10200. It incorporates multiple layers of security protocols, including encryption and authentication mechanisms, to protect against unauthorized access and potential cyber threats. The platform also features robust filtering and Denial of Service (DoS) protection, ensuring that VoIP services remain stable and reliable even under adverse conditions.

Quality of Service (QoS) management is another critical characteristic of the BTS 10200. It allows for traffic prioritization to ensure that voice signals maintain clarity and reduce latency. Through advanced traffic shaping and management techniques, service providers can enhance the overall user experience even during peak usage periods.

Furthermore, the BTS 10200 supports a wide array of management and monitoring tools, enabling network administrators to gain insights into performance metrics, traffic trends, and system health. This data-driven approach allows for intelligent decision-making and proactive maintenance.

In summary, the Cisco Systems BTS 10200 is a powerful, secure, and scalable solution for managing voice and data services in today's complex telecommunications environment. Its combination of protocol support, robust security measures, QoS capabilities, and management tools positions it as a key asset for service providers looking to enhance their offerings and ensure reliable communications for their users.