Session border controllers occupy a unique position in the network architecture enabling them to protect the quality of end user communications and enforce operators' Service Level Agreements. The Newport 1460 architecture has been uniquely designed to allow QoS to be managed on an individual session basis whilst also ensuring that key services such as emergency calling can always be accommodated. The Newport 1460 session border controller performs the following key functions to achieve and enforce true carrier class QoS.
As shown above, the model allows the operator to layer the network into end customer groups, logical VLAN groups and physical interfaces and groups of interfaces. Whenever a new call is attempted, the model is examined, the appropriate resources reserved for that call and the total available resource decremented appropriately. If there are no resources available in the model, the call is rejected. The 1460 also provides an interface to external 3rd party policy management systems if required. The Newport 1460 SAC algorithm ensures that emergency calls can always be carried by the network.
2. Policing. The call establishment signalling protocols enable the subscribers' terminals to automatically negotiate the codec type that will be used for the duration of the call, and hence, the call's data rate. Each call is policed individually by the Newport 1460 against the data rate of the negotiated codec. Any traffic significantly above the negotiated rate will be discarded. This, in turn, underpins the accurate and consistent view of network resources offered by the SAC function.
3. Anti-Tromboning. (or Media Release) This feature optimises the use of the access network. For example, in an IP-Centrex service environment, the call may be most effectively transported entirely within the subscribers' private network. As shown in the diagram below, the Newport 1460 SAC algorithm is able to differentiate between internal and external calls ensuring that the corporate only pays for the access bandwidth that they use.
4. QoS policing and remapping. The Newport 1460 allows the operator to monitor the quality marking of a users data (Type of Service bits and DiffServ Code Point bits) and ensure that it matches the quality negotiated during call set up thus avoiding some users gaining higher levels of service at the expense of other users service levels. In the case of interconnect, the Newport 1460 allows remapping of ToS and DSCP bits to ensure conformance with internal network policy.
The unique nature of the Newport 1460 hardware accelerated architecture allows it to perform QoS and bandwidth management in a coordinated and effective way with little impact on overall system performance.
For more information on the Newport Networks 1460 QoS and Bandwidth Management capabilities please refer to our white paper here.
Architecture
Updates
