1. Service Level Agreement
Rashid Mijumbi
Laia Nadal Reixats
Communications Network Management

2. SLA definition
A Service Level Agreement (SLA) is an element of a formal, negociated, commercial contract between two parties. Ex) Service provider-Customer.
It documents responsabilities and roles of both parties from service ordering to service termination.
Who are interested in SLA?
Service Providers, Solution Providers, Vendors, Others.
Definitions
Actors, Services, Service Level Agreement, Measurements.

3. SLA management in eTOM context

4. Actors Service Provider (SP): Customer:
A general reference to an entity that provides telecommunication services to customers and other users.
Customer:
Is an organization which has a business relationship with a Service Provider for the provision of network services.
Both customer and SP may be in a value chain of service delivery.

5. Actors: Main SLA-related entities
This figure shows that a given actor A1 may need to function as a Customer to A2, A3 and A4 in order to provide services to its customers Ax and Ay. This concept is defined as an Integrator role.

6. Service definition
eTOM (enhanced Telecom Operating Model), a TM Forum Group defines Service as:
“Services are developed by a Service Provider for sale within Products. The same service may be included in multiple products, packaged differently, with different pricing, etc.”

7. Service overview
In this figure is depicted the SP, SLA and Customer concepts. As well as Service, Product ( distinguishing between Product Offering, which is the abstract description of the Product, and the Product instance, which is an actual delivered product between an SP and a Customer). The Customer-Facing Service is part of a Product and is transparent for the Customer.

8. Service Level Agreement
Metric: A metric is a commonly identified and mesureable concept. It can characterize a Service or a Product.
KPIs: Are technical metrics when applied to networking.
KQIs: A metric that captures the overall performance of a Service or Product. Typically expressed as a percentage of customers or resources.

9. Service Level Agreement
In the picture are represented three different scenarios. SLA defines what needs to be measured and which measuring and reporting processes are used. SLSs ( Service Level Specifications) define parameters that should be measured and thesholds which are the specification of actual values to be achieved.

10. Measurements
Estimator: A value obtained by a certain method, and expected to be close to the real value.
Measurement Point: Physical and logical demarcation point where an estimator method can be applied.
SLM: Service Level Measurement
SLS: Service Level Specification

11. Service Level Measurement
Service Level Measurement at time T (SLM(T)).

12. SLA Life Cycle Process
SLA activation / Execution phase: Once the Service starts being delivered, the SLA support infrastructure is activated.
SLA modification phase: SLA is modified during its lifetime.
SLA termination phase: If the contract is finished the SLA doesn’t apply any more.
In the initial phase (SLA activation phase) the support infrastructure is activated and permanently verifies whether the SLA is satisfied by collecting measurements, and constructing the SLM(T)s and procedures reports. When the SLA is not satisfied the SLA Violation procedures are activated.

13. SLA Specification process
Step 1: Initial SLA draft
Step2: Verify SLA completeness. Ensure that SLA is complete in terms of SLS parameters.
Step 3: Verify SLA feasibility.
A validation of the chosen metrics.
Step 4: Document and review
Step 5: Finalize

14. SLA PROCESS FLOWS
Process flows represent the way that the business activities can work together to satisfy a particular need.
Process flows can be built using the eTOM process elements in order to address business needs identified in each case.
SLA Process Interactions
Normal Execution
Execution with SLA violation
Assessment
Process Elements in the eTOM framework are intended as an exhaustive list i.e an enterprise uses only the eTOM process elements when categorizing business activities within process implementations. Should an exception arise where some activity is identified as not bieng supported by any existing process element, then a new process element would be created and added to the eTOM framework in order to maitain its role as a comprehensive process framework.
Process flows represent the way that the business activities (in the form of the process elements) can work together to satisfy a particular need. An exhaustive list of process flows will never be completed because needs are continually changing, but this is not an issue as the individual scenarios, and the process flows developed around them, provide insight that contributes to an enhanced understanding of how the eTOM framework can be used. What is important for an enterprise that is trying to improve its efficiency by re-using its process and IT capabilities, is that it must ensure that process flows are built using business activities that are categorized using only the eTOM process elements.
The flow diagrams are organised into “swim lanes” or horizontal tracks that follow the layers visible in the eTOM frame (e.g. CRM, SM&O etc)
With each swim lane, individual processses are then shown with interractions that link the processes with in and between the swim lanes. These interactions are primarily concerned with event transitions, i.e the interaction is labelled to identify the event that causes the transition from the originating to the destination process
Process flows are initiated and terminated in the diagrams by boxes that may be shown outside the swim lane area. Arrowed boxes pointing right-wards indicate events (initiating a flow), while arrowed boxes pointing left-wards indicate results (terminating flow).
Normal execution, also known as steady state, is the phase where the customer receives service on all the contracted and instantiated service instances.
During normal operation, perfomance data that is used for general monitoring of service level as well as for longer-term capacity prediction is collected on an ongoing basis from the service-providing infrasctructure by Resource Data Collection and Processing
During normal operation, perfomance data from external service components of third part service providers is sent on an ongoing basis to

15. 9 5 4 3 7 8 1 6 2 NORMAL EXECUTION OF SLA SERVICE
PERFOMANCE DATA DURING NORMAL OPERATION 10 12 9 11 5 4 3 7 8 1 6 2

16. NORMAL EXECUTION OF SLA SERVICE
THRESHOLD CROSSING ALERTS AND RESOURCE FAILURE ALARMS (1) 9 8 7 16 6 10 15 17 11 3 5 14 2 4 12 13 1

17. NORMAL EXECUTION OF SLA SERVICE
THRESHOLD CROSSING ALERTS AND RESOURCE FAILURE ALARMS (2)
NORMAL EXECUTION OF SLA SERVICE 26 25 24 23 21 22 20 19 18

18. EXECUTION WITH SLA VIOLATION (1)3 10 1 2 9 5 4 16 11 15 7 8 9 14 6 9 13 10 12

19. EXECUTION WITH SLA VIOLATION (2)22 25 26 24 21 23 20 19 18 17

20. CUSTOMER NEEDS HAVE CHANGED
ASSESSMENT (1)
CUSTOMER NEEDS HAVE CHANGED 2 5 1 3 4

21. INTERNAL ASSESSMENTS AT THE CUSTOMER AND SERVICE LAYERS14 2 1 12 13 3 8 11 7 10 4 6 9 5