C. Demichelis, P. Chimento, Instantaneous packet delay variation metric for IPPM, IPPM Internet Draft, 2000.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....the wire time of the packet arriving on the link observed by the sender to the wire time of the last bit of the packet observed by the receiver. The difference of these two values is the oneway delay. Instantaneous Packet Delay Variation (IPDV) is formally defined by the IPPM working group Draft [13]. It is based on one way delay measurements and it is defined for (consecutive) pairs of packets. A singleton IPDV measurement requires two packets. If we let D i be the one way delay of the i th packet, then the IPDV of the packet pair is defined as D i D i 1 . According to common usage, ....

C. Demichelis, P. Chimento, Instantaneous Packet Delay Variation Metric for IPPM; ippm draft, work in progress

....One way delay is computed as the difference between the timestamp at the source and the timestamp at the receiver in the OAM packet, provided that the clocks are synchronised. The delay variation is then defined as the difference between the one way delay for consecutive packets [20], or the difference between the one way delay for each packet and the mean delay during the measurement period [15] Since the timestamps are samples from every N packet in the stream the result depends on the sampling rate. # Uu. tuf# ir##rr rqtr qr Since the number of packets transmitted ....

....packet is distributed and Figure 8 shows the corresponding distribution measured by means of monitoring packets inserted between blocks of 50 data packets on the average. The delay variation is computed as the delay for each packet minus the average delay during the measurement period ( 15] and [20]) Figure 9 shows a histogram of the variation in delay calculated according to this definition based on timestamps from every packet. The corresponding histogram based on OAM packets sent between every 50 packet on the average can be seen in Figure 10. The estimated maximum delay variation lie ....

Demichelis C., Chimento P.: "Instantaneous Packet Delay Variation Metric for IPPM", Internet-draft, , July 2000.

....delay and loss. The following table is a partial summary: Document Reference Topics Covered RFC 2679 [2] one way delay measurement RFC 2680 [3] one way loss measurement RFC 2681 [4] two way (round trip) delay measurement ippm loss pattern [20] one way loss pattern characterization ippm ipdv [12] jitter measurement RFC 2679 has several key characteristics. First, it states that the clock di erence and drift at both sender and receiver must be synchronized or compensated for, but it does not specify how to achieve synchronization. Second, the inter packet sending interval should conform ....

....packet is considered to have in nite delay, which a ects median nding. Fourth, it notes that determining whether a packet is lost can be hard, but it does not provide any particular suggestion except that the tester should record the policy used (e.g. a 5 second timeout) The ippm ipdv draft [12] computes jitter by subtracting one way delays of two consecutive packets. It is equivalent to the RTP [40] de nition of jitter. This is also the de nition we use here for all the tables and gures in this paper. The ippm loss pattern draft [20] de nes several new metrics to capture packet loss ....

C. Demichelis and P. Chimento. Instantaneous packet delay variation metric for IPPM. Internet Draft, Internet Engineering Task Force, June 1999. Work in progress.

....active measurement streams, which must take care not to exceed the service parameters of these reservations. Required active metrics for each test path include: the IETF IPPM one way packet loss metric [16] an instantaneous one way packet delay variation metric based on the draft documents [17] and [18] periodic traceroutes for each behavior aggregate (formal metrics such as for interdomain path stability could later be derived from these) The second class of required metrics must be obtained passively either through sniffing of interdomain links at QBone boundary nodes or ....

C. Demichelis, Instantaneous Packet Delay Variation Metric for IPPM, Internet Draft, November 1998.

....delay and loss. The following table is a partial summary: Document Reference Topics Covered RFC 2679 [2] one way delay measurement RFC 2680 [3] one way loss measurement RFC 2681 [4] two way (round trip) delay measurement ippm loss pattern [20] one way loss pattern characterization ippm ipdv [12] jitter measurement RFC 2679 has several key characteristics. First, it states that the clock di erence and drift at both sender and receiver must be synchronized or compensated for, but it does not specify howtoachieve synchronization. Second, the inter packet sending interval should conform to ....

....packet is considered to have in nite delay, which a ects median nding. Fourth, it notes that determining whether a packet is lost can be hard, but it does not provide any particular suggestion except that the tester should record the policy used (e.g. a 5 second timeout) The ippm ipdv draft [12] computes jitter by subtracting one way delays of two consecutive packets. It is equivalent to the RTP [40] de nition of jitter. This is also the de nition we use here for all the tables and gures in this paper. The ippm loss pattern draft [20] de nes several new metrics to capture packet loss ....

C. Demichelis and P. Chimento. Instantaneous packet delayvariation metric for IPPM. Internet Draft, Internet Engineering Task Force, June 1999. Work in progress.

....and application of these metrics, but actual implementations and applications are understood to be beyond the scope of this working group. Completed work so far by IPPM has been published recently as Request for Comments (RFC) 2330 [22] and current works in progress have been documented in [2, 3, 8, 14, 16]. 2 The framework outlined in [22] is of informational category and does not specify an Internet standard of any kind. In the following, we summarize the key points discussed in [22] The authors of [22] attempted to set up a common goal of the IP performance metrics, which is to achieve a ....

....as discussed above is to provide the raw data from which we can analyze and estimate the network performance and congestion status. To achieve this, performance and reliability metrics for paths through the Internet must be defined. We start with the following metrics, which have been discussed in [2, 3, 8, 16]. Path Bandwidth, Throughput, and Goodput: Path Bandwidth, measured in bytes (or bits) per second, is the minimum link capacity among all the links from a source host to the destination host. Path bandwidth sets up a fundamental limit that data can be transferred from one end system to another ....

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C. Demichelis, "Instantaneous Packet Delay Variation Metric for IPPM," Internet Draft draft-ietf-ippmipdv -00.txt, March 1998, http://www.ietf.org/internet-drafts/draft-ietf-ippm-ipdv-00.txt.

....wire time of the packet arriving on the link observed by the sender to the wire time of the last bit of the packet observed by the receiver. The difference of these two values is the one way delay. Instantaneous Packet Delay Variation (IPDV) is formally defined by the IPPM working group draft [8]. It is based on one way delay measurements and it is defined for (consecutive) pairs of packets. A singleton IPDV measurement requires two packets. If we let D i be the oneway delay of the i th packet, then the IPDV of the packet pair is defined as D i D i 1 . According to common usage, ....

C. Demichelis, P. Chimento, Instantaneous Packet Delay Variation Metric for IPPM; ippm draft, work in progress.

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C. Demichelis, P. Chimento, Instantaneous packet delay variation metric for IPPM, IPPM Internet Draft, 2000.

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Demichelis, C., Chimento, P.: Instantaneous Packet Delay Variation Metric for IPPM, ippm draft, work in progress.

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