TRANSPORT QUALITY IMPROVEMENT MEASUREMENT METHOD and STANDARDIZATION Transport Network Quality 27 JANUARY 2015
IPPM OVERVIEW What is IPPM IPPM (Internet Protocol Performance Monitoring) is a technique to measure transport network performance IPPM has capability to measure real-time performance of end-to-end IP connection between two wireless nodes • •
IP Layer Layer 2 Physical Layer
Counter Parameter
Key Performance Index
Note: Metro-E < 20 ms
IP Layer Layer 2 Physical Layer
Description
Threshold
VS.IPPM.Forword.DropMeans
Average Forward Packet Loss Rate of IPPM
< 0.1%
VS.IPPM.MaxRttDelay
Maximum Ro und Trip Delay of IPPM
< 40 ms
IPPM MEASUREMENT METHOD IPPM Measurement Method Samples are taken every five seconds in the specified measurement period. If we are using 1 hour or 60 minutes measurement period, it means there will be 720 samples of measurement. The system obtains the number of discarded packets once every five seconds. With t his, the system obtains the total number of dis carded packets in one measurement period. The loss rate is calculated by dividing the discarded packets with total packets . •
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Description of Peak Drop per Hour measurement result: For example there are 50 Samples of Discarded Packet with various value of Packet Loss The value of Peak Drop will be taken from the BIGGEST Discarded Packet (for example 15%) • •
Description of Mean Drop per Hour measurement result: For example there are 50 Samples of Discarded Packet with various value of Packet Loss The system will calculates the AVERAGE of 50 Samples of Discarded Packet The value of Mean Drop will be taken from the result of the AVERAGE calculation (for example 0.05%) • • •
RECOMMENDATION OF IPPM COUNTER : HUAWEI Counter Introduction Counter ID : 67204127 Counter Name : VS.IPPM.Forword.DropMeans Description : Average Forward Packet Loss Rate of IPPM • • •
This counter provides the Forward Packet Loss Rate of the IPPATH in the specified measurement period. The packet loss rate is calculated as follows:
Peak Drop Rate Peak Drop Rate packet loss is just the result of one sample in the specified measurement period, so this counter is unscientific to evaluate the network. For example, take 1 hour as measurement period, there are 720 samples during one measurement period, and only one sample is peak value. The peak value can just prove that some packets are lost in some five seconds. Actually, time with packet loss even less than five seconds. Peak packet loss rate is susceptible when the traffic is very low. For example, there are 50 packets in one sample, and if one packet is lost, the loss rate should be 2%. •
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Mean Drop Rate Average packet loss rate can reflect total number of discarded packets in one measurement period, it can also reflect more samples during one measurement period, so it is more scientific. For commercial network, there always many users share the transmission, and these users also will share the packet loss, so the impact is less than the situation that there is only one user. •
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RECOMMENDATION OF IPPM COUNTER Samples of Discarded Packet M easurement For 1 hour measurement period, there are 720 samples of measurement. Of 720 samples, 25 samples are discarded packet. Peak Drop is Packet Loss with the largest value of discarded samples = 45% Mean Drop is Packet Loss with average value of 25 discarded samples = 5.12% In this case, average packet loss reflect total number of 25 discarded packets, while peak drop is just a result of one sample of 25 discarded packets. • • • • •
Conclusion : Recommendation Counter of Packet Loss monitoring is AVERAGE Packet Loss Rate Threshold of The Packet Loss Rate Results of Huawei laboratory show that higher speed service more stringent about packet loss rate. Huawei suggest average packet loss rate less than 0.1% to be t he reference standard, and this proposal can meet the requirements of 84M HSPA+ service, it can also meet the standardized QCI characteristics which are defined by 3GPP. • •
RECOMMENDATION OF IPPM COUNTER : ERICSSON IuB HS Limit Counter Name Description • •
: pmCapAllocIubHsLimitingRatioSpi : Percentage of times where IuB congestion has occurred
Packet Loss (HS Frame Loss)
Key Performance Index Packet Loss IuB HS Limit
: less than 0.1% : less than 20%
IPPM PATTERN FORMULA CALCULATION Packet Loss Pattern Formula Calculation Concept is done by examining IPPM graph of packet loss which performed by M2000 NMS. Measurement are performed during 7 days with a measurement period of 1 hour (60 minutes). It will generate 168 measurement of maximum result of packet loss. By examining IPPM graph of Packet Loss, Node-B is called having a problem if packet loss occurred at least 3 times a day or 21 times a week (12.5%) of average packet loss. Packet Loss Counter (average_21) determine the state of CLEAR, SPIKE and CONSECUTIVE as following: Counter = 0 : CLEAR Counter < 21 : SPIKE Counter >= 21 : CONSECUTIVE • •
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IPPM DATA MINING IPPM Data Mining Performance data of Node-B and IuB transport generated by M2000 Server M2000 Server then deliver the data to external equipment called Servo Aggregator Server Servo Aggregator Server synchronized the data and deliver to Transport Data Mining Server Transport Data Mining Server manages the synchronized data then generates requirement data such as IuB Packet Loss and Latency Transport Data Mining Server equipped with Automatic Report Generator, Raw Data Exporter and Automatic Packet Loss Pattern Detector • • • • •
Next Plan: IuB Usage, IuB Drop Flow Control, IuB HS Limit, HSDPA Throughput
ANALYSIS OF PACKET LOSS IMPACTS : VOICE QUALITY Packet Loss on the Voice Quality Voice Quality can be measured based on R Factor and MOS parameter as follow: R Factor Transmission quality rating which estimates the relative impairments to voice quality MOS Mean Opinion Score, voice quality parameter based on customer opinion of satisfaction Table below describes the voice quality based on customer satisfaction based on MOS value • • • •
Packet Loss Rate
Average MOS
Minimum MOS 3.66
0
3.86
0.01%
3.85
3.46
0.05%
3.8
3.29
0.10%
3.78
3.27
0.50%
3.62
3.01
1%
3.44
2.72
2.50%
2.96
2.2
5%
2.49
1.81
10%
1.91
1.54
12%
1.75
Can't Hear
ANALYSIS OF PACKET LOSS IMPACTS : DATA QUALITY (HSDPA THROUGHPUT)
Packet Loss Rate (%)
1.8M DL Throughput (Mbps)
3.6M DL Throughput (Mbps)
7.2M DL Throughput (Mbps)
0
1790
3254.7
6822
0.01
1790
2988.7
6565
0.05
1790
2892.6
6286
0.1
1790
2899.4
5948
0.5
1750
2478.6
4996
1
1660
2173.3
4595
2.5
1430
1918.5
4270
5
217 4
213 2
488
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