1. Voice Performance Measurement and related technologies
Part1: IP SLA

2. outline IP SLA principles IP SLA components
Highlighted features of IP SLA
IP SLA performance metrics
IP SLA operations

3. What is IP SLA
Cisco IP SLA is an embedded feature set in Cisco IOS Software that allows you to analyze service levels for IP applications and services

4. The basic principle of IP SLA
An active measurement that uses injected test packets (synthetic traffic) marked with a time stamp to calculate performance metrics.

5. IP SLA measurements benefits
The results allow indirect assessment of the network, such as Service-Level Agreements (SLA) and QoS class definitions.

6. IP SLA components
IP SLA consists of two components, both implemented in Cisco devices: • Mandatory source device, which generates, receives, and analyzes the traffic. • The IP SLA Responder, which is optionally used to increase accuracy and measurement details.

8. Using time stamps
By adding time stamps to the measurement packets at the destination device, the IP SLA Responder allows the elimination of the measurement packet processing time on the destination device. The IP SLA Responder listens on any standard or user-defined port for UDP, TCP, and Frame Relay packets generated by the IP SLA source.

10. T4 is the time stamp at the source after receiving the traffic
RTT= T4-T1
Latency (one way)=T2-T1
Where :
T4 is the time stamp at the source after receiving the traffic
T1 is the time stamp at the source when generating traffic
T2 is the time stamp at the target when receiving traffic

11. IP SLA scope
IP SLA is an example of a device instrumentation technique that does not overlap between accounting and performance, because it is dedicated to performance measurement

12. IP SLA is applicable to both service providers and enterprises for performance management.

13. Highlighted features of IP SLA
Network performance monitoring
SLA monitoring
IP service network health assessment
Edge-to-edge network availability monitoring
Voice over IP (VoIP) performance monitoring
Application-aware monitoring
Accuracy
Flexible operations
Pervasiveness
Troubleshooting of network operation

14. Network performance monitoring
Network performance monitoring— Measures delay, jitter, packet loss, packet ordering, and packet corruption in the network.

15. SLA monitoring
SLA monitoring— Provides service-level monitoring and verification

16. IP service network health assessment
IP service network health assessment— Verifies that the existing QoS settings are sufficient for new IP services.

17. Edge-to-edge network availability monitoring
Edge-to-edge network availability monitoring— Provides proactive verification and connectivity testing of network resources (for example, indicates the network availability of a web server).

18. Voice over IP (VoIP) performance monitoring
Voice over IP (VoIP) performance monitoring— Analyzes critical parameters for a VoIP deployment, which are not only jitter and packet loss, but also the Mean Opinion Score (MOS) and Impairment/Calculated Planning Impairment Factor (ICPIF) values. The ICPIF value represents predefined combinations of loss and delay.

19. Application-aware monitoring
Application-aware monitoring— IP SLA can emulate traffic up to the application level—for example, DNS, DHCP, and web server requests—and can measure the related performance statistics.

20. Accuracy
Accuracy— Microsecond granularity for jitter delay measurements offers the required precision for business-critical applications.

21. Flexible operations
Flexible operations— Offer various kinds of scheduling, alerting, and triggered measurements

22. Pervasiveness
Pervasiveness— IP SLA is implemented in Cisco networking devices ranging from low-end to highend routers and switches. This avoids the deployment and management of dedicated measurement boxes.

23. Troubleshooting of network operation
Troubleshooting of network operation— Provides consistent, reliable measurement that proactively identifies performance and connectivity problems.

24. IP SLA collects the following performance metrics:
• Delay (both round-trip and one-way) • Jitter (one-way) • Packet loss (one-way) • Packet sequencing (packet ordering) • Packet corruption detection • Path (per hop) • Connectivity (one-way) • FTP server or HTTP website download time • Voice quality scores (MOS, ICPIF)

25. The various IP SLA operations can be classified as follows:
• ICMP-based operations for Echo, Path Echo, and Path Jitter.
• UDP-based operations, such as echo, jitter, DNS, and DHCP.
• TCP-based operations, such as TCP Connect, FTP, HTTP.
• Layer 2 operations, such as Frame Relay, ATM, and MPLS.
• VoIP-related operations, such as VoIP Jitter

26. Abbreviations Meaning IOS Internetwork Operating System ICPIF
Impairment/Calculated Planning Impairment Factor
ICMP
Internet Control Message Protocol
MPLS
Multiprotocol Label Switching
ATM
Asynchronous Transfer Mode