draft-ietf-ippm-loss-pattern-01.txt | draft-ietf-ippm-loss-pattern-02.txt | |||
---|---|---|---|---|

Internet-Draft | Internet-Draft | |||

Expiration Date: December, 1999 R. Koodli | Expiration Date: April, 2000 R. Koodli | |||

R. Ravikanth | R. Ravikanth | |||

Nokia Research Center | Nokia Research Center | |||

June, 1999 | October, 1999 | |||

One-way Loss Pattern Sample Metrics | One-way Loss Pattern Sample Metrics | |||

<draft-ietf-ippm-loss-pattern-01.txt> | <draft-ietf-ippm-loss-pattern-02.txt> | |||

STATUS OF THIS MEMO | STATUS OF THIS MEMO | |||

This document is an Internet-Draft and is in full conformance with all | This document is an Internet-Draft and is in full conformance with all | |||

provisions of Section 10 of RFC2026. | provisions of Section 10 of RFC2026. | |||

Internet-Drafts are working documents of the Internet Engineering Task | Internet-Drafts are working documents of the Internet Engineering Task | |||

Force (IETF), its areas, and its working groups. Note that other groups | Force (IETF), its areas, and its working groups. Note that other groups | |||

may also distribute working documents as Internet- Drafts. | may also distribute working documents as Internet- Drafts. | |||

skipping to change at page 3, line 44 | skipping to change at page 3, line 44 | |||

and received (denoted by r) packets. | and received (denoted by r) packets. | |||

r r r x r r x x x r x r r x x x | r r r x r r x x x r x r r x x x | |||

Then, with i assigned as follows | Then, with i assigned as follows | |||

1 1 1 1 1 1 | 1 1 1 1 1 1 | |||

i: 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 | i: 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 | |||

f(P_i) is, | f(P_i) is, | |||

f(P_i): 0 0 0 1 0 1 0 0 0 1 0 1 1 0 0 0 | f(P_i): 0 0 0 1 0 0 1 1 1 0 1 0 0 1 1 1 | |||

and there are four loss periods in the above sequence | and there are four loss periods in the above sequence | |||

begining at P_3, P_6, P_10, and P_13. | beginning at P_3, P_6, P_10, and P_13. | |||

4. Definitions for Samples of One-way Loss Distance, | 4. Definitions for Samples of One-way Loss Distance, | |||

and One-way Loss Period. | and One-way Loss Period. | |||

4.1 Metric Name: | 4.1 Metric Name: | |||

4.1.1 Type-P-One-Way-Loss-Distance-Stream | 4.1.1 Type-P-One-Way-Loss-Distance-Stream | |||

4.1.2 Type-P-One-Way-Loss-Period-Stream | 4.1.2 Type-P-One-Way-Loss-Period-Stream | |||

4.2 Metric Parameters | 4.2 Metric Parameters | |||

skipping to change at page 4, line 45 | skipping to change at page 4, line 45 | |||

the lost packet and the previously lost packet. The sample would | the lost packet and the previously lost packet. The sample would | |||

consist of <loss distance, loss> pairs. This definition assumes that | consist of <loss distance, loss> pairs. This definition assumes that | |||

sequence numbers of successive test packets increase monotonically by | sequence numbers of successive test packets increase monotonically by | |||

one. The loss distance associated with the very first packet loss is | one. The loss distance associated with the very first packet loss is | |||

considered to be zero. | considered to be zero. | |||

The sequence number of a test packet can be derived from the timeseries | The sequence number of a test packet can be derived from the timeseries | |||

sample collected by performing the loss measurement according to the | sample collected by performing the loss measurement according to the | |||

methodology in [AKZ]. For example, if a loss sample consists of | methodology in [AKZ]. For example, if a loss sample consists of | |||

{<T0,0>, <T1,0>, <T2,1>, <T3,0>, <T4,0>}, the sequence numbers of the | {<T0,0>, <T1,0>, <T2,1>, <T3,0>, <T4,0>}, the sequence numbers of the | |||

five test packets sent at T0, T1, T2, T3, and T4 can be 0, 1, 2, 3 and 4 | five test packets sent at T0, T1, T2, T3, and T4 can be 0, 1, 2, 3 and | |||

respectively, or 100, 101, 102, 103 and 104 respectively, etc. | 4 respectively, or 100, 101, 102, 103 and 104 respectively, etc. | |||

{Packet loss may also be considered as a result of exceeding some delay | {Packet loss may also be considered as a result of exceeding some delay | |||

threshold. This is particularly applicable to delay-sensitive audio | threshold. This is particularly applicable to delay-sensitive audio | |||

(or video) applications. | (or video) applications. | |||

} | } | |||

4.4.2 Type-P-One-Way-Loss-Period-Stream | 4.4.2 Type-P-One-Way-Loss-Period-Stream | |||

We start a counter 'n' at an initial value of zero. This counter is | We start a counter 'n' at an initial value of zero. This counter is | |||

incremented by one each time a lost packet satisfies the Definition 3.3. | incremented by one each time a lost packet satisfies the Definition 3.3. | |||

skipping to change at page 6, line 15 | skipping to change at page 6, line 15 | |||

4.6 Discussion: | 4.6 Discussion: | |||

The Loss-Distance-Stream metric allows one to study the separation | The Loss-Distance-Stream metric allows one to study the separation | |||

between packet losses. This could be useful in determining a | between packet losses. This could be useful in determining a | |||

"spread factor" associated with the packet loss rate. For | "spread factor" associated with the packet loss rate. For | |||

example, for a given packet loss rate, the proposed metric | example, for a given packet loss rate, the proposed metric | |||

indicates how the losses are spread. On the other hand, | indicates how the losses are spread. On the other hand, | |||

the Loss-Period-Stream metric allows the study of loss burstiness | the Loss-Period-Stream metric allows the study of loss burstiness | |||

for each occurrence of loss. Note that a single loss period of | for each occurrence of loss. Note that a single loss period of | |||

length 'n' can account for a significant portion of the overall | length 'n' can account for a significant portion of the overall | |||

loss rate. | loss rate. Note also that it is possible to measure distance between | |||

loss bursts seprated by one or more successfully received packets: See | ||||

Section 5.4, and 5.5 | ||||

4.7 Sampling Considerations: | 4.7 Sampling Considerations: | |||

The proposed metrics can be used independent of the | The proposed metrics can be used independent of the | |||

particular sampling method used. We note that Poisson sampling | particular sampling method used. We note that Poisson sampling | |||

may not yield appropriate values for these metrics for | may not yield appropriate values for these metrics for | |||

certain real-time applications such as voice over IP, as well as to | certain real-time applications such as voice over IP, as well as to | |||

TCP-based applications. For real-time applications, it may be more | TCP-based applications. For real-time applications, it may be more | |||

appropriate to use the ON-OFF [Sriram] model, in which an ON period | appropriate to use the ON-OFF [Sriram] model, in which an ON period | |||

starts with certain probability 'p', during which certain number of | starts with certain probability 'p', during which certain number of | |||

skipping to change at page 7, line 26 | skipping to change at page 7, line 26 | |||

"loss period" entry ranging from 1 - Type-P-One-Way-Loss-Period-Total. | "loss period" entry ranging from 1 - Type-P-One-Way-Loss-Period-Total. | |||

Thus the total number of pairs in this statistic equals | Thus the total number of pairs in this statistic equals | |||

Type-P-One-Way-Loss-Period-Total. In each pair, the "length" is | Type-P-One-Way-Loss-Period-Total. In each pair, the "length" is | |||

obtained by counting the number of pairs, <loss period, loss>, in the | obtained by counting the number of pairs, <loss period, loss>, in the | |||

metric Type-P-One-Way-Loss-Period-Stream which have first entry equal | metric Type-P-One-Way-Loss-Period-Stream which have first entry equal | |||

to "loss period." | to "loss period." | |||

{Note: This statistic represents the number of packets lost in each | {Note: This statistic represents the number of packets lost in each | |||

loss period.} | loss period.} | |||

5.4 Example | 5.4 Type-P-One-Way-Inter-Loss-Period-Lengths | |||

This statistic measures distance between successive loss periods. It | ||||

takes the form of a set of pairs | ||||

<loss period, inter-loss-period-length>, with the | ||||

"loss period" entry ranging from 1 - Type-P-One-Way-Loss-Period-Total, | ||||

and "inter-loss-period-length" is the loss distance between the last | ||||

packet considered lost in "loss period" 'i-1', and the first packet | ||||

considered lost in "loss period" 'i', where 'i' ranges from 2 to | ||||

Type-P-One-Way-Loss-Period-Total. The "inter-loss-period-length" | ||||

associated with the first "loss period" is defined to be zero. This | ||||

statistic allows one to consider, for example, two loss periods each | ||||

of length greater than one (implying loss burst), but separated by a | ||||

distance of 2 to belong to the same loss burst if such a consideration | ||||

is deemed useful. | ||||

5.5 Example | ||||

We continue with the same example as in Section 4.4.3. The three | We continue with the same example as in Section 4.4.3. The three | |||

statistics defined above will have the following values. | statistics defined above will have the following values. | |||

+ Let delta = 2. | + Let delta = 2. | |||

In Type-P-One-Way-Loss-Distance-Stream | In Type-P-One-Way-Loss-Distance-Stream | |||

{<0,0>,<0,1>,<0,0>,<0,0>,<3,1>,<0,0>,<2,1>,<0,0>,<2,1>,<1,1>}, there | {<0,0>,<0,1>,<0,0>,<0,0>,<3,1>,<0,0>,<2,1>,<0,0>,<2,1>,<1,1>}, there | |||

are 3 loss distances that violate the delta of 2. Thus, | are 3 loss distances that violate the delta of 2. Thus, | |||

Type-P-One-Way-Loss-Noticeable-Rate = 3/5 | Type-P-One-Way-Loss-Noticeable-Rate = 3/5 | |||

skipping to change at page 7, line 53 | skipping to change at page 8, line 19 | |||

Type-P-One-Way-Loss-Period-Total = 4 | Type-P-One-Way-Loss-Period-Total = 4 | |||

+ In Type-P-One-Way-Loss-Period-Stream | + In Type-P-One-Way-Loss-Period-Stream | |||

{<0,0>,<1,1>,<0,0>,<0,0>,<2,1>,<0,0>,<3,1>,<0,0>,<4,1>,<4,1>}, the | {<0,0>,<1,1>,<0,0>,<0,0>,<2,1>,<0,0>,<3,1>,<0,0>,<4,1>,<4,1>}, the | |||

lengths of individual loss periods are 1, 1, 1 and 2 respectively. | lengths of individual loss periods are 1, 1, 1 and 2 respectively. | |||

Thus, | Thus, | |||

Type-P-One-Way-Loss-Period-Lengths = {<1,1>,<2,1>,<3,1>,<4,2>} | Type-P-One-Way-Loss-Period-Lengths = {<1,1>,<2,1>,<3,1>,<4,2>} | |||

+ In Type-P-One-Way-Loss-Period-Stream | ||||

{<0,0>,<1,1>,<0,0>,<0,0>,<2,1>,<0,0>,<3,1>,<0,0>,<4,1>,<4,1>}, the | ||||

loss periods 1 and 2 are separated by 3 (5-2), loss periods 2 and 3 | ||||

are separated by 2 (7-5), and 3 and 4 are separated by 2 (9-7). | ||||

Thus, | ||||

Type-P-One-Way-Inter-Loss-Period-Lengths = {<1,0>,<2,3>,<3,2>,<4,2>} | ||||

6. Security Considerations | 6. Security Considerations | |||

Since this draft proposes sample metrics based on the base loss metric | Since this draft proposes sample metrics based on the base loss metric | |||

defined in [AKZ], it inherits the security considerations mentioned in | defined in [AKZ], it inherits the security considerations mentioned in | |||

[AKZ]. | [AKZ]. | |||

7. Acknowledgements | 7. Acknowledgements | |||

Many thanks to Matt Zekauskas for the constructive feedback on the draft. | Many thanks to Matt Zekauskas for the constructive feedback on the draft. | |||

Thanks to Guy Almes for encouraging the work, and Vern Paxson for all the | Thanks to Guy Almes for encouraging the work, and Vern Paxson for the | |||

comments during the IETF meetings. | comments during the IETF meetings. Thanks to Steve Glass for making the | |||

presentation at the Oslo meeting. | ||||

8. References | 8. References | |||

[AKZ] G. Almes and S. Kalindindi and M. Zekauskas, "A One-way Packet | [AKZ] G. Almes and S. Kalindindi and M. Zekauskas, "A One-way Packet | |||

Loss Metric for IPPM", Internet Draft <draft-ietf-ippm-loss-07.txt>, | Loss Metric for IPPM", RFC 2680, September 1999 | |||

May 1999 | ||||

[Bolot] J.-C. Bolot and A. vega Garcia, "The case for FEC-based | [Bolot] J.-C. Bolot and A. vega Garcia, "The case for FEC-based | |||

error control for Packet Audio in the Internet", ACM Multimedia | error control for Packet Audio in the Internet", ACM Multimedia | |||

Systems, 1997. | Systems, 1997. | |||

[Borella] M. S. Borella, D. Swider, S. Uludag, and G. B. Brewster, | [Borella] M. S. Borella, D. Swider, S. Uludag, and G. B. Brewster, | |||

"Internet Packet Loss: Measurement and Implications for End-to-End | "Internet Packet Loss: Measurement and Implications for End-to-End | |||

QoS," Proceedings, International Conference on Parallel Processing, | QoS," Proceedings, International Conference on Parallel Processing, | |||

August 1998. | August 1998. | |||

skipping to change at page 8, line 53 | skipping to change at page 9, line 25 | |||

TCP-friendly rate adjustment protocol for continuous media flows | TCP-friendly rate adjustment protocol for continuous media flows | |||

over best-effort networks", short paper presentation in | over best-effort networks", short paper presentation in | |||

ACM SIGMETRICS'99. Available as Umass Computer Science tech report | ACM SIGMETRICS'99. Available as Umass Computer Science tech report | |||

from ftp://gaia.cs.umass.edu/pub/Padhye98-tcp-friendly-TR.ps.gz | from ftp://gaia.cs.umass.edu/pub/Padhye98-tcp-friendly-TR.ps.gz | |||

[Paxson] V. Paxson, "End-to-end Internet packet dynamics", Computer | [Paxson] V. Paxson, "End-to-end Internet packet dynamics", Computer | |||

Communication review, Proceedings of ACM SIGCOMM'97 Conference, | Communication review, Proceedings of ACM SIGCOMM'97 Conference, | |||

Cannes, France, September 1997, 27(4), pages 139-152, October 1997 | Cannes, France, September 1997, 27(4), pages 139-152, October 1997 | |||

[frame-work] V. Paxson, G. Almes, J. Mahdavi, and M. Mathis, | [frame-work] V. Paxson, G. Almes, J. Mahdavi, and M. Mathis, | |||

"Framework for IP Performance Metrics", RFC 2330. | "Framework for IP Performance Metrics", RFC 2330, May 1998. | |||

[Sriram] K. Sriram and W. Whitt, "Characterizing superposition | [Sriram] K. Sriram and W. Whitt, "Characterizing superposition | |||

arrival processes in packet multiplexers for voice and data", IEEE | arrival processes in packet multiplexers for voice and data", IEEE | |||

Journal on Selected Areas of Communication, September 1986, pages | Journal on Selected Areas of Communication, September 1986, pages | |||

833-846 | 833-846 | |||

[Yajnik] M. Yajnik, J. Kurose and D. Towsley, "Packet loss | [Yajnik] M. Yajnik, J. Kurose and D. Towsley, "Packet loss | |||

correlation in the MBONE multicast network", Proceedings of IEEE | correlation in the MBONE multicast network", Proceedings of IEEE | |||

Global Internet, London, UK, November 1996. | Global Internet, London, UK, November 1996. | |||

End of changes. | ||||

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