**6.2 Trial infrastructure for SLA violation**

The implementation architecture features two sub-architectures for the service provisioning and for service management and correction services.

**The Supply Architecture** which contains an IMS network that includes both the signalling and the media planes. The architecture includes three routers to transmit the media stream; a central router supports the IMS system. The PCRF (Policy and Charging Rule Function) is becoming an autonomous entity and includes other features such as policy management, and both edge routers include the PCEF (Policy and Charging Enforcement Function) functionality to receive and execute policies or PCC rules (Figure 14).

Monitoring and management architecture: SLM & M is divided into two layers


eTOM-Conformant IMS Assurance Management 69

The results expose several parameters relating to monitoring service and performance of SLM&M in centralized and distributed architecture, and response time in trouble detection

Case 1: The QoS offered to Alice and Bob matches SLA contract, perceived video quality is

Case 2: the network conditions, hence video quality, deteriorate proportionally to mass of

Case 3: competing services overload the routers: queues fill in gateways, impacting delay and jitter. Routers discard packets in excess, this causes static pixels in video (Figure 17) and

competing services for lost packets and reduced flow rate (Figure 16).

**6.4 Results** 

and SLA violation.

satisfying (Figure 15).

Fig. 15. Video bandwidth =128kbps.

Fig. 16. Video bandwidth =76kbps.

in some cases service cancellation.

**6.4.1 SLA verification in centralized architecture:** 


Fig. 14. Centralized trial infrastructure.

The supply architecture provides a set of IMS services, when a client requests a VoD streaming service, the provisioning chain stimulates IMS entities to provide a resource reservation and QoS management. The SLM&M in supply, after ordering operation, start collection of configuration data for a normal SLA execution. Anomaly detection or exceeding threshold causes an activation of SLA violation processes for restoring service into normal level.

The SLM&M must be reactive by rapid detection of QoS degradation or anomalies, followed by an attempt to resolve troubles, that activates the Assurance process and if necessary the Fulfilment process.

#### **6.3 Scenarios**

The test scenario includes three cases, a customer Alice with Platinum class that requires a VoD service:

