Saa Config Template

Monitoring of Jitter, Delay and Packet loss in WAN links Document Owner: Vishal Arora

Introduction The Cisco IOS IP Service Level Agreements (SLAs) Internet Control Message Protocol (ICMP) jitter operation provides the capability to generate stream of ICMP packets between a Cisco IOS device (source) and any other IP device (destination) to gather network performance-related statistics. Available statistical measurements for the IP SLAs ICMP jitter operation include latency, round-trip time, jitter (interpacket delay variance), and packet loss.

The Importance of Measuring Delay, Jitter, and Packet Loss With the emergence of new applications on data networks, it is becoming increasingly important for customers to accurately predict the impact of new application rollouts. Not long ago, it was easy to allocate bandwidth to applications and let the applications adapt to the exploding nature of traffic flows through timeout and retransmission functions of the upper layer protocols. Now, however, new world applications, such as voice and video, are more susceptible to changes in the transmission characteristics of data networks. It is imperative to understand the traffic characteristics of the network before deployment of new world applications to ensure successful implementations.

Defining Delay, Jitter, and Packet Loss Delay is the time taken from point•to•point in a network. Delay can be measured in either one•way or round•trip delay. One•way delay calculations require expensive sophisticated test gear and are beyond the budget and expertise of most enterprise customers. However, measuring round•trip delay is easier and requires less expensive equipment. To get a general measurement of one•way delay, measure round•trip delay and divide the result by two. Jitter is the variation in delay over time from point•to•point. If the delay of transmissions varies too widely in a VoIP call, the call quality is greatly degraded. The amount of jitter tolerable on the network is affected by the depth of the jitter buffer on the network equipment in the path. The more jitter buffer available, the more the network can reduce the effects of jitter. Packet loss is losing packets along the data path, which severely degrades the performance of the link.The delay, jitter, and packet loss measurements can aid in the correct design and configuration of traffic prioritization, as well as buffering parameters in the data network equipment.

IP SLA Responder Cisco IOS IP SLAs Responder is a component embedded in the destination Cisco router whose functionality is to respond to Cisco IOS IP SLAs request packets. The responder adds timestamps to the echoed packets to allow unidirectional packet loss, latency, and

jitter measurements to a Cisco device. The accuracy of the measurements is improved significantly if the responder is used. Requirement To monitor WAN links of all the Aircel sites connected in MPLS cloud with respect to RTT, Jitter and Packet Loss.

Solution As NNM exists in IDC and all the sites are connected to it so this is suggested to consider it as HUB/Source location for polling. All other sites would be considered as SPOKE/Destination. The SAA would be configure on IDC MPLS router and would collect defined parameters between WAN links.

Configuration template At Source router

enable config t ip sla 1 [Begins configuration for an IP SLAs operation and enters IP SLA configuration mode.] icmp-jitter <destination IP> source-ip <source ip> [Begins configuration for an IP SLAs operation and enters IP SLA configuration mode.]

frequency 60 [Sets the rate at which a specified IP SLAs operation repeats in seconds] ip sla reaction-configuration 1 react jitterAvg thresholdvalue 5 3 threshold-type immediate action-type trapOnly [Configures an action (SNMP trap. or IP SLAs trigger) to occur based on violations of thresholds for Average Jitter i.e jitterAvg ]

ip sla reaction-configuration 1 react rtt threshold-value 60 10 threshold-type immediate action-type trapOnly [Configures an action (SNMP trap. or IP SLAs trigger) to occur based on violations of thresholds for rtt ]

ip sla reaction-configuration 1 react packetLoss thresholdvalue 5 3 threshold-type immediate action-type trapOnly [Configures an action (SNMP trap. or IP SLAs trigger) to occur based on violations of thresholds for Packet loss ]

ip sla schedule 1 life forever start-time now [Configures the scheduling parameters for an individual IP SLAs operation.]

Note: Values given in template are ideal, real values will be depending upon application usage.

At Destination Router

enable config t ip sla responder [Enables IP SLAs Responder functionality on a Cisco device.] exit SLA statistics Router# sh ip sla statistics Round Trip Time (RTT) for Index 1 Type of operation: icmpJitter Latest RTT: 49 milliseconds Latest operation start time: *23:50:01.974 UTC Thu Feb 19 2009 Latest operation return code: OK RTT Values: Number Of RTT: 10 RTT Min/Avg/Max: 49/49/50 Latency one-way time: Number of Latency one-way Samples: 0 Source to Destination Latency one way Min/Avg/Max: 0/0/0 Destination to Source Latency one way Min/Avg/Max: 0/0/0 Jitter Time: Number of SD Jitter Samples: 9 Number of DS Jitter Samples: 9 Source to Destination Jitter Min/Avg/Max: 0/1/2 Destination to Source Jitter Min/Avg/Max: 0/0/0 Packet Late Arrival: 0 Out Of Sequence: 0 Source to Destination: 0 Destination to Source 0 In both Directions: 0 Packet Skipped: 0 Packet Unprocessed: 0 Packet Loss: 0 Loss Period Length Min/Max: 0/0 Number of successes: 22 Number of failures: 0 Operation time to live: Forever