End-to-End Performance Measurement Scenarios

IP datacom networks, as the mainstream of datacom networks, are large in scale and provide various access modes. To maximize carriers' return on investment, reduce network construction costs, and evolve the existing network smoothly into a Long Term Evolution (LTE) network, an IP RAN solution is introduced.

IP RANs require performance measurement for SLA compliance and routine O&M performance management. As the bearer network quality (delay, jitter, and packet loss) affects the radio service quality, the bearer network department must provide optimal methods to detect the network operating status. In addition, if the service quality deteriorates, the bearer network must be able to provide its own performance data to help fault locating.

IP RAN provides a variety of solutions. The following section describes the application of IP FPM end-to-end performance measurement in HVPN, and L2+L3 mixed VPN scenarios. The service type can be the 3G Ethernet service (signaling, voice, and data), S1 service (signaling, voice, and data), OM service, or IP clock service. The service flow is identified by the source IP address, destination IP address, and DSCP value.

HVPN Scenarios

Figure 1 shows an HVPN networking. Table 1 lists how to deploy IP FPM in an HVPN scenario.

Figure 1 IP FPM application in an HVPN scenario

**Table 1** IP FPM deployment in an HVPN scenario
Deployment Object	IP FPM Deployment
TLP deployment	Performance measurement can be implemented for E2E services and local switching services on IP RANs. On the network shown in Figure 1: For E2E services, configure IP FPM on both ends (CSG, RSG1, and RSG2) of the Layer 3 service flow; deploy TLPs on the UNIs of the CSG, RSG1, and RSG2 and bind the TLPs to the access-side interfaces (TLPs must be bound to the outbound interfaces on both RSGs). For local switching services, deploy TLPs only on the CSG sub-interfaces connecting to the base stations.
DCP deployment	Configure the CSG, RSG1, and RSG2 as DCPs to send measurement data to the MCP.
MCP deployment	If routes are reachable between the access and aggregation networks, deploy the MCP on an RSG. If routes are unreachable between the access and aggregation networks, deploy the MCP on an AGG. On the network in Figure 1, deploy the MCP on RSG1.
Clock deployment	Configure the network time protocol (NTP) or 1588v2 so that all device clocks can be synchronized. To implement IP FPM one-way delay measurement, you must configure 1588v2 for clock synchronization. If not, the measurement is incorrect. To implement IP FPM two-way delay measurement or packet loss measurement, configure either NTP or 1588v2 for clock synchronization. 1588v2 implements higher-precision clock synchronization than NTP. Using 1588v2 is recommended.

In E2E VPN and native IP+L3VPN scenarios, deploy IP FPM in the same manner as that in HVPN scenarios.

L2+L3 Mixed VPN Scenarios

Figure 2 shows an L2+L3 mixed VPN networking. Table 2 lists how to deploy IP FPM in an L2+L3 mixed VPN scenario.

Figure 2 IP FPM application in an L2+L3 mixed VPN scenario

**Table 2** IP FPM deployment in an L2+L3 mixed VPN scenario
Deployment Object	IP FPM Deployment
TLP deployment	For E2E services, deploy TLPs on the AC interfaces that carry services (Layer 2 user interfaces on the CSG and Layer 2/Layer 3 user interfaces on RSGs). Configure flow characteristics based on the 5-tuple, start measurement and counting, and send measurement data to the MCP through protocol packets
DCP deployment	Configure the CSG, RSG1, and RSG2 as DCPs to send measurement data to the MCP.
MCP deployment	Routes are unreachable between the access and aggregation networks, and the CSG does not have routes to RSGs. Therefore, deploy the MCP on an AGG. On the network in Figure 2, deploy the MCP on AGG1.
Clock deployment	Same as that in an HVPN scenario

In packet loss measurement, ARP request messages are filtered out and unknown unicast traffic is also filtered out based on the source IP addresses. The causes are as follows:

ARP request messages are generated on AGGs in the downstream direction.
Broadcast traffic is generated in the downstream direction if the VSI has not learned MAC addresses.

Summary

IP FPM offers the following benefits:

Supports E2E performance measurement on large-scale networks.
Supports service-based packet loss and delay measurement with high precision.
Applies to various networking scenarios.