draft-ietf-bmwg-dsmterm-04.txt   draft-ietf-bmwg-dsmterm-05.txt 
Network Working Group Jerry Perser Network Working Group Jerry Perser
INTERNET-DRAFT Spirent INTERNET-DRAFT Spirent
Expires in: April 2003 David Newman Expires in: August 2003 David Newman
Network Test Network Test
Sumit Khurana Sumit Khurana
Telcordia Telcordia
Shobha Erramilli Shobha Erramilli
QNetworx QNetworx
Scott Poretsky Scott Poretsky
Avici Systems Avici Systems
October 2002 February 2002
Terminology for Benchmarking Network-layer Terminology for Benchmarking Network-layer
Traffic Control Mechanisms Traffic Control Mechanisms
<draft-ietf-bmwg-dsmterm-04.txt> <draft-ietf-bmwg-dsmterm-05.txt>
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
skipping to change at page 1, line 44 skipping to change at page 1, line 44
in progress." in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
Table of Contents Table of Contents
1. Introduction .............................................. 2 1. Introduction .............................................. 3
2. Existing definitions ...................................... 3 2. Existing definitions ...................................... 3
3. Term definitions ............................................3 3. Term definitions ............................................4
3.1 Configuration Terms 3.1 Configuration Terms
3.1.1 Classification .........................................3 3.1.1 Classification .........................................4
3.1.2 Codepoint Set ..........................................4 3.1.2 Codepoint Set ..........................................4
3.1.3 Congestion .............................................4 3.1.3 Forwarding Congestion ..................................5
3.1.4 Congestion Management ..................................5 3.1.4 Congestion Management ..................................6
3.1.5 Flow ...................................................6 3.1.5 Flow ...................................................6
3.2 Measurement Terms 3.2 Measurement Terms
Network-layer Traffic Control Mechanisms Network-layer Traffic Control Mechanisms
3.2.1 Channel Capacity .......................................7 3.2.1 Channel Capacity .......................................7
3.2.2 Conforming .............................................7 3.2.2 Conforming .............................................8
3.2.3 Nonconforming ..........................................8 3.2.3 Nonconforming ..........................................8
3.2.4 Delay ..................................................8 3.2.4 Delay ..................................................9
3.2.5 Jitter .................................................9 3.2.5 Jitter ................................................10
3.2.6 Undifferentiated Response .............................10 3.2.6 Undifferentiated Response .............................11
3.3 Sequence Tracking 3.3 Sequence Tracking
3.3.1 In-sequence Packet ....................................10 3.3.1 In-sequence Packet ....................................11
3.3.2 Out-of-order Packet ...................................11 3.3.2 Out-of-order Packet ...................................12
3.3.3 Duplicate Packet ......................................11 3.3.3 Duplicate Packet ......................................12
3.3.4 Stream ................................................12 3.3.4 Stream ................................................13
3.3.5 Test Sequence number .................................12 3.3.5 Test Sequence number .................................13
3.4 Vectors ...................................................13 3.4 Vectors ...................................................14
3.4.1 Intended Vector .......................................13 3.4.1 Intended Vector .......................................14
3.4.2 Offered Vector ........................................14 3.4.2 Offered Vector ........................................15
3.4.3 Expected Vectors 3.4.3 Expected Vectors
3.4.3.1 Expected Forwarding Vector ........................14 3.4.3.1 Expected Forwarding Vector ........................15
3.4.3.2 Expected Loss Vector ..............................15 3.4.3.2 Expected Loss Vector ..............................16
3.4.3.3 Expected Sequence Vector ..........................16 3.4.3.3 Expected Sequence Vector ..........................16
3.4.3.4 Expected Instantaneous Delay Vector ...............16 3.4.3.4 Expected Instantaneous Delay Vector ...............17
3.4.3.5 Expected Average Delay Vector .....................17 3.4.3.5 Expected Average Delay Vector .....................18
3.4.3.6 Expected Maximum Delay Vector .....................17 3.4.3.6 Expected Maximum Delay Vector .....................18
3.4.3.7 Expected Minimum Delay Vector .....................18 3.4.3.7 Expected Minimum Delay Vector .....................19
3.4.3.8 Expected Instantaneous Jitter Vector ..............19 3.4.3.8 Expected Instantaneous Jitter Vector ..............20
3.4.3.9 Expected Average Jitter Vector ....................19 3.4.3.9 Expected Average Jitter Vector ....................21
3.4.3.10 Expected Peak-to-peak Jitter Vector ..............20 3.4.3.10 Expected Peak-to-peak Jitter Vector ..............21
3.4.4 Output Vectors 3.4.4 Output Vectors
3.4.4.1 Forwarding Vector .................................21 3.4.4.1 Forwarding Vector .................................22
3.4.4.2 Loss Vector .......................................21 3.4.4.2 Loss Vector .......................................22
3.4.4.3 Sequence Vector ...................................22 3.4.4.3 Sequence Vector ...................................23
3.4.4.4 Instantaneous Delay Vector ........................23 3.4.4.4 Instantaneous Delay Vector ........................24
3.4.4.5 Average Delay Vector ..............................24 3.4.4.5 Average Delay Vector ..............................25
3.4.4.6 Maximum Delay Vector ..............................25 3.4.4.6 Maximum Delay Vector ..............................26
3.4.4.7 Minimum Delay Vector ..............................25 3.4.4.7 Minimum Delay Vector ..............................26
3.4.4.8 Instantaneous Jitter Vector .......................26 3.4.4.8 Instantaneous Jitter Vector .......................27
3.4.4.9 Average Jitter Vector .............................27 3.4.4.9 Average Jitter Vector .............................28
3.4.4.10 Peak-to-peak Jitter Vector .......................28 3.4.4.10 Peak-to-peak Jitter Vector .......................29
4. Security Considerations ....................................29 4. Security Considerations ....................................30
5. References .................................................29 5. Normative References .......................................30
6. Author's Address ...........................................30 6. Informative References .....................................31
7. Full Copyright Statement ...................................31 7. Author's Address ...........................................32
8. Full Copyright Statement ...................................33
Network-layer Traffic Control Mechanisms
1. Introduction 1. Introduction
This document describes terminology for the benchmarking of This document describes terminology for the benchmarking of
devices that implement traffic control based on IP precedence or devices that implement traffic control based on IP precedence or
diff-serv code point criteria. diff-serv code point criteria.
New terminology is needed because most existing measurements New terminology is needed because most existing measurements
assume the absence of congestion and only a single per-hop- assume the absence of congestion and only a single per-hop-
Network-layer Traffic Control Mechanisms
behavior. This document introduces several new terms that will behavior. This document introduces several new terms that will
allow measurements to be taken during periods of congestion. allow measurements to be taken during periods of congestion.
Another key difference from existing terminology is the definition Another key difference from existing terminology is the definition
of measurements as observed on egress as well as ingress of a of measurements as observed on egress as well as ingress of a
device/system under test. Again, the existence of congestion device/system under test. Again, the existence of congestion
requires the addition of egress measurements as well as those requires the addition of egress measurements as well as those
taken on ingress; without observing traffic leaving a taken on ingress; without observing traffic leaving a
device/system it is not possible to say whether traffic-control device/system it is not possible to say whether traffic-control
mechanisms effectively dealt with congestion. mechanisms effectively dealt with congestion.
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For the sake of clarity and continuity this RFC adopts the For the sake of clarity and continuity this RFC adopts the
template for definitions set out in Section 2 of RFC 1242. template for definitions set out in Section 2 of RFC 1242.
Definitions are indexed and grouped together in sections for ease Definitions are indexed and grouped together in sections for ease
of reference. of reference.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in
RFC 2119. RFC 2119.
Network-layer Traffic Control Mechanisms
3. Term definitions 3. Term definitions
3.1 Configuration Terms 3.1 Configuration Terms
3.1.1 Classification 3.1.1 Classification
Definition: Definition:
Network-layer Traffic Control Mechanisms
Selection of packets based on the contents of packet header Selection of packets based on the contents of packet header
according to defined rules. according to defined rules.
Discussion: Discussion:
Packets can be selected based on the DS field or IP Packets can be selected based on the DS field or IP
Precedence in the packet header. Classification can also be Precedence in the packet header. Classification can also be
based on Multi-Field (MF) criteria such as IP Source and based on Multi-Field (MF) criteria such as IP Source and
destination addresses, protocol and port number. destination addresses, protocol and port number.
Classification determines the per-hop behaviors and traffic Classification determines the per-hop behaviors and traffic
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point gets is subject to the DUT classifying packets to map point gets is subject to the DUT classifying packets to map
to the correct PHB. Moreover, the forwarding treatment in to the correct PHB. Moreover, the forwarding treatment in
general is also dependent on the complete set of offered general is also dependent on the complete set of offered
vectors. vectors.
Measurement Units: Measurement Units:
n/a n/a
See Also: See Also:
3.1.3 Congestion Network-layer Traffic Control Mechanisms
3.1.3 Forwarding Congestion
Definition: Definition:
A condition in which one or more egress interfaces are A condition in which one or more egress interfaces are
offered more packets than are forwarded. offered more packets than are forwarded.
Discussion: Discussion:
Network-layer Traffic Control Mechanisms This condition is a superset of the overload definition
[Ma98]. The overload definition assumes the congestion is
introduced strictly by the tester on ingress of a DUT/SUT.
That may or may not be the case here.
This condition is a superset of the overload definition [2]. Another difference between Forwarding Congestion and overload
The overload definition assumes the congestion is introduced occurs when the SUT comprises multiple elements, in that
strictly by the tester on ingress of a DUT/SUT. That may or Forwarding Congestion may occur at multiple points. Consider
may not be the case here. an SUT comprising multiple edge devices exchanging traffic
with a single core device. Depending on traffic patterns, the
edge devices may induce congestion on multiple egress
interfaces on the core device. In contrast, overload [Br91]
deals only with overload on ingress.
Another difference between congestion and overload occurs Packet Loss, not increased Delay, is the metric to indicate
when the SUT comprises multiple elements, in that congestion the condition of Forwarding Congestion. Packet Loss is a
may occur at multiple points. Consider an SUT comprising deterministic indicator of Forwarding Congestion. While
multiple edge devices exchanging traffic with a single core increased delay may be an indicator of Forwarding Congestion,
device. Depending on traffic patterns, the edge devices may it is a non-deterministic indicator of Forwarding Congestion.
induce congestion on multiple egress interfaces on the core External observation of increased delay to indicate
device. In contrast, overload [1] deals only with overload on congestion is in effect external observation of Incipient
ingress. Congestion. [Ra99] states that it is impractical to build a
black-box test to externally observe Incipient Congestion in
a router. For the purpose of "black-box" testing a DUT/SUT,
Packet Loss as the indicator of Forwarding Congestion is
used.
Throughput [1] defines the lower boundary of congestion. Throughput [Br91] defines the lower boundary of Forwarding
Throughput is the maximum offered rate with no congestion. Congestion. Throughput is the maximum offered rate with no
At offered rates above throughput, the DUT/SUT is considered Forwarding Congestion. At offered rates above throughput,
congested. the DUT/SUT is considered congested.
Ingress observations alone are not sufficient to cover all Ingress observations alone are not sufficient to cover all
cases in which congestion may occur. A device with an cases in which Forwarding Congestion may occur. A device with
infinite amount of memory could buffer an infinite amount of an infinite amount of memory could buffer an infinite amount
packets, and eventually forward all of them. However, these of packets, and eventually forward all of them. However,
packets may or may not be forwarded during the test duration. these packets may or may not be forwarded during the test
Even though ingress interfaces accept all packets without duration. Even though ingress interfaces accept all packets
loss, this hypothetical device may still be congested. without loss, this hypothetical device may still be
congested.
The definition presented here explicitly defines congestion Network-layer Traffic Control Mechanisms
as an event observable on egress interfaces. Regardless of
internal architecture, any device that cannot forward packets Forwarding Congestion, indicated by occurrence of packet
on one or more egress interfaces is congested. loss, is one type of congestion for a DUT/SUT. Congestion
Collapse [Na84] is defined as the state in which buffers are
full and all arriving packets must be dropped across the
network. Incipient Congestion [Ra99] is defined as
congestion that produces increased delay without packet loss.
The definition presented here explicitly defines Forwarding
Congestion as an event observable on egress interfaces.
Regardless of internal architecture, any device that cannot
forward packets on one or more egress interfaces is under
Forwarding Congestion.
Measurement units: Measurement units:
none none
See Also: See Also:
Gateway Congestion Control Survey [8] Gateway Congestion Control Survey [Ma91]
3.1.4 Congestion Management 3.1.4 Congestion Management
Definition: Definition:
An implementation of one or more per-hop-behaviors to avoid An implementation of one or more per-hop-behaviors to avoid
or minimize the condition of congestion. or minimize the condition of congestion.
Discussion: Discussion:
Congestion management may seek either to control congestion Congestion management may seek either to control congestion
or avoid it altogether. Such mechanisms classify packets or avoid it altogether. Such mechanisms classify packets
based upon IP Precedence or DSCP settings in a packet's IP based upon IP Precedence or DSCP settings in a packet's IP
header. header.
Network-layer Traffic Control Mechanisms
Congestion avoidance mechanisms seek to prevent congestion Congestion avoidance mechanisms seek to prevent congestion
before it actually occurs. before it actually occurs.
Congestion control mechanisms gives one or flows (with a Congestion control mechanisms gives one or flows (with a
discrete IP Precedence or DSCP value) preferential treatment discrete IP Precedence or DSCP value) preferential treatment
over other classes during periods of congestion. over other classes during periods of congestion.
Measurement units: Measurement units:
n/a n/a
See Also: See Also:
3.1.5 Flow 3.1.5 Flow
Definition: Definition:
A flow is a one or more of packets sharing a common intended A flow is a one or more of packets sharing a common intended
pair of source and destination interfaces. pair of source and destination interfaces.
Network-layer Traffic Control Mechanisms
Discussion: Discussion:
Packets are grouped by the ingress and egress interfaces they Packets are grouped by the ingress and egress interfaces they
use on a given DUT/SUT. use on a given DUT/SUT.
A flow can contain multiple source IP addresses and/or A flow can contain multiple source IP addresses and/or
destination IP addresses. All packets in a flow must enter destination IP addresses. All packets in a flow must enter
on the same ingress interface and exit on the same egress on the same ingress interface and exit on the same egress
interface, and have some common network layer content. interface, and have some common network layer content.
Microflows [3] are a subset of flows. As defined in [3], Microflows [Ni98] are a subset of flows. As defined in
microflows require application-to-application measurement. In [Ni98], microflows require application-to-application
contrast, flows use lower-layer classification criteria. measurement. In contrast, flows use lower-layer
Since this document focuses on network-layer classification classification criteria. Since this document focuses on
criteria, we concentrate here on the use of network-layer network-layer classification criteria, we concentrate here on
identifiers in describing a flow. Flow identifiers also may the use of network-layer identifiers in describing a flow.
reside at the data-link, transport, or application layers of Flow identifiers also may reside at the data-link, transport,
the ISO model. However, identifiers other than those at the or application layers of the ISO model. However, identifiers
network layer are out of scope for this document. other than those at the network layer are out of scope for
this document.
A flow may contain a single code point/IP precedence value or A flow may contain a single code point/IP precedence value or
may contain multiple values destined for a single egress may contain multiple values destined for a single egress
interface. This is determined by the test methodology. interface. This is determined by the test methodology.
Measurement units: Measurement units:
n/a n/a
See Also: See Also:
Microflow [3] Microflow [Ni98]
Streams Streams
Network-layer Traffic Control Mechanisms
3.2 Measurement Terms 3.2 Measurement Terms
3.2.1 Channel Capacity 3.2.1 Channel Capacity
Definition: Definition:
The maximum forwarding rate [2] at which none of the offered The maximum forwarding rate [Ma98] at which none of the
packets are dropped by the DUT/SUT. offered packets are dropped by the DUT/SUT.
Discussion: Discussion:
Channel capacity measures the packet rate at the egress Channel capacity measures the packet rate at the egress
interface(s) of the DUT/SUT. In contrast, throughput as interface(s) of the DUT/SUT. In contrast, throughput as
defined in RFC 1242 measures the packet rate is based on the defined in RFC 1242 measures the packet rate is based on the
ingress interface(s) of the DUT/SUT. ingress interface(s) of the DUT/SUT.
Ingress-based measurements do not account for congestion of Ingress-based measurements do not account for congestion of
the DUT/SUT. Channel capacity, as an egress measurement, does the DUT/SUT. Channel capacity, as an egress measurement, does
take congestion into account. take congestion into account.
Network-layer Traffic Control Mechanisms
Understanding channel capacity is a necessary precursor to Understanding channel capacity is a necessary precursor to
any measurement involving congestion. Throughput numbers can any measurement involving congestion. Throughput numbers can
be higher than channel capacity because of queueing. be higher than channel capacity because of queueing.
This measurement differs from forwarding rate at maximum This measurement differs from forwarding rate at maximum
offered load (FRMOL) [2] in that it is intolerant of loss. offered load (FRMOL) [Ma98] in that it is intolerant of loss.
Measurement units: Measurement units:
N-octet packets per second N-octet packets per second
See Also: See Also:
Throughput [1] Throughput [Br91]
Forwarding Rate at Maximum Offered Load [2] Forwarding Rate at Maximum Offered Load [Ma98]
3.2.2 Conforming 3.2.2 Conforming
Definition: Definition:
Packets which lie within specific rate, delay, or jitter Packets which lie within specific rate, delay, or jitter
bounds. bounds.
Discussion: Discussion:
A DUT/SUT may be configured to allow a given traffic class to A DUT/SUT may be configured to allow a given traffic class to
consume a given amount of bandwidth, or to fall within consume a given amount of bandwidth, or to fall within
Network-layer Traffic Control Mechanisms
predefined delay or jitter boundaries. All packets that lie predefined delay or jitter boundaries. All packets that lie
within specified bounds are then said to be conforming, within specified bounds are then said to be conforming,
whereas those outside the bounds are nonconforming. whereas those outside the bounds are nonconforming.
Measurement units: Measurement units:
n/a n/a
See Also: See Also:
Expected Vector Expected Vector
Forwarding Vector Forwarding Vector
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Packets that do not lie within specific rate, delay, or Packets that do not lie within specific rate, delay, or
jitter bounds. jitter bounds.
Discussion: Discussion:
A DUT/SUT may be configured to allow a given traffic class to A DUT/SUT may be configured to allow a given traffic class to
consume a given amount of bandwidth, or to fall within consume a given amount of bandwidth, or to fall within
predefined delay or jitter boundaries. All packets that do predefined delay or jitter boundaries. All packets that do
not lie within these bounds are then said to be not lie within these bounds are then said to be
nonconforming. nonconforming.
Network-layer Traffic Control Mechanisms
Measurement units: Measurement units:
n/a n/a
See Also: See Also:
Expected Vector Expected Vector
Forwarding Vector Forwarding Vector
Offered Vector Offered Vector
Conforming Conforming
3.2.4 Delay 3.2.4 Delay
Definition: Definition:
The time interval starting when the last bit of the input IP The time interval starting when the last bit of the input IP
packet reaches the input port of the DUT/SUT and ending when packet reaches the input port of the DUT/SUT and ending when
the last bit of the output IP packet is seen on the output the last bit of the output IP packet is seen on the output
port of the DUT/SUT. port of the DUT/SUT.
Discussion: Discussion:
Delay is measured the same regardless of the type of DUT/SUT. Delay differs from latency [Br91] and one-way delay [Al99] in
Latency [1] require some knowledge of whether the DUT/SUT is several key regards:
a "store and forward" or a "bit forwarding" device. The fact
that a DUT/SUT's technology has a lower delay than another
technology should be visible.
Network-layer Traffic Control Mechanisms 1. Latency [Br91] assumes knowledge of whether the DUT/SUT
uses "store and forward" or "bit forwarding" technology.
Delay is delay, regardless of the technology being measured.
By specifying the metric to be inside the Internet protocol, 2. Delay is a last-in, last-out (LILO) measurement, unlike
the tester is relieved from specifying the start/end for the last-in, first-out method [Br91] or the first-in, last-
every data link layer protocol that IP runs on. This avoids out method [Al99].
determining if the start/end delimiters are included in the
frame. Also heterogeneous data link protocol can be used in The LILO method most closely simulates the way a network-
layer device actually processes an IP datagram. IP datagrams
are not passed up and down the stack unless they are
complete, and processing begins only once the last bit of the
IP datagram has been received.
Further, the LILO method has an additive property, where the
sum of the parts MUST equal the whole. This is a key
difference from [Br91] and [Al99]. For example, the delay
added by two DUTs MUST equal the sum of the delay of the
DUTs. This may or may not be the case with [Br91] and [Al99].
3. Delay measures the IP datagram only, unlike [Br91], which
also includes link layer overhead.
A metric focused exclusively on the Internet protocol
relieves the tester from specifying the start/end for every
link layer protocol that IP runs on. This avoids the need to
determine whether the start/stop delimiters are included. It
also allows the use of heterogeneous link layer protocols in
a test. a test.
The measurement point at the end closely simulates the way an Network-layer Traffic Control Mechanisms
internet datagram is processed. An internet datagram is not
passed up or down the stack unless it is complete.
Completion occurs once the last bit of the IP packet has been
received.
Delay can be run at any offered load. Recommend at or below 4. Delay can be measured at any offered load, whereas latency
the channel capacity for non-congested delay. For congested [Br99] is measured only at the throughput level.
delay, run the offered load above the channel capacity.
For example, non-congested delay may be measured with an
offered load that does not exceed the channel capacity, while
congested delay may involve an offered load that exceeds
channel capacity.
5. Delay SHOULD NOT be used as an absolute indicator of
DUT/SUT Forwarding Congestion. While delay may rise when
offered load nears or exceeds channel capacity, there is no
universal point at which delay can be said to indicate the
presence or absence of Forwarding Congestion.
Measurement units: Measurement units:
Seconds. Seconds.
See Also: See Also:
Latency [1] Latency [Br91]
Latency [Al99]
One-way Delay [Br99]
3.2.5 Jitter 3.2.5 Jitter
Definition: Definition:
The absolute value of the difference between the arrival The absolute value of the difference between the arrival
delay of two consecutive packets belonging to the same delay of two consecutive packets belonging to the same
stream. stream.
Discussion: Discussion:
The delay fluctuation between two consecutive packets in a The delay fluctuation between two consecutive packets in a
stream is reported as the jitter. Jitter can be expressed as stream is reported as the jitter. Jitter can be expressed as
|D(i) - D(i-1)| where D equals the delay and i is the test |D(i) - D(i-1)| where D equals the delay and i is the test
sequence number. The measurement does not include lost sequence number. The measurement does not include lost
packets. packets.
Jitter can be determined by the ipdv [6] (IP Delay Variation) Jitter can be determined by the ipdv [De02] (IP Delay
by taking the absolute value of the ipdv. The two metrics Variation) by taking the absolute value of the ipdv. The two
will produce different mean values. _Mean Jitter_ will metrics will produce different mean values. _Mean Jitter_
produce a positive value, where the _mean ipdv_ is typically will produce a positive value, where the _mean ipdv_ is
zero. typically zero.
Measurement units: Measurement units:
Seconds Seconds
See Also: See Also:
Jitter variation [5] Jitter variation [Ja99]
ipdv [6] ipdv [De02]
interarrival jitter [7] interarrival jitter [Sc96]
Network-layer Traffic Control Mechanisms Network-layer Traffic Control Mechanisms
3.2.6 Undifferentiated Response 3.2.6 Undifferentiated Response
Definition: Definition:
The vector(s) obtained when mechanisms used to support diff- The vector(s) obtained when mechanisms used to support diff-
serv or IP precedence are disabled. serv or IP precedence are disabled.
Discussion: Discussion:
Enabling diff-serv or IP precedence mechanisms may impose Enabling diff-serv or IP precedence mechanisms may impose
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3.3.1 In-sequence Packet 3.3.1 In-sequence Packet
Definition: Definition:
A received packet with the expected Test Sequence number. A received packet with the expected Test Sequence number.
Discussion: Discussion:
In-sequence is done on a stream level. As packets are In-sequence is done on a stream level. As packets are
received on a stream, each packet's Test Sequence number is received on a stream, each packet's Test Sequence number is
compared with the previous packet. Only packets that match compared with the previous packet. Only packets that match
the expected are considered in-sequence. the expected Test Sequence number are considered in-sequence.
Packets that do not match the expected Test Sequence number Packets that do not match the expected Test Sequence number
are counted as _not in-sequence_ or out-of-sequence. Every are counted as _not in-sequence_ or out-of-sequence. Every
packet that is received is either in-sequence or out-of- packet that is received is either in-sequence or out-of-
sequence. Subtracting the in-sequence from the received sequence. Subtracting the in-sequence from the received
packets (for that stream) can derive the out-of-sequence packets (for that stream) can derive the out-of-sequence
count. count.
Two types of events will prevent the in-sequence from Two types of events will prevent the in-sequence from
incrementing: packet loss and reordered packets. incrementing: packet loss and reordered packets.
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Streams are not restricted to a pair of source and Streams are not restricted to a pair of source and
destination interfaces as long as all packets are tracked as destination interfaces as long as all packets are tracked as
a single entity. A mulitcast stream can be forward to a single entity. A mulitcast stream can be forward to
multiple destination interfaces. multiple destination interfaces.
Measurement units: Measurement units:
n/a n/a
See Also: See Also:
Flow Flow
MicroFlow [3] MicroFlow [Ni98]
Test sequence number Test sequence number
3.3.6 Test Sequence number 3.3.6 Test Sequence number
Definition: Definition:
A field in the IP payload portion of the packet that is used A field in the IP payload portion of the packet that is used
to verify the order of the packets on the egress of the to verify the order of the packets on the egress of the
DUT/SUT. DUT/SUT.
Discussion: Discussion:
The traffic generator sets the test sequence number value and The traffic generator sets the test sequence number value and
the traffic receiver checks the value upon receipt of the the traffic receiver checks the value upon receipt of the
packet. The traffic generator changes the value on each packet. The traffic generator changes the value on each
Network-layer Traffic Control Mechanisms
packet transmitted based on an algorithm agreed to by the packet transmitted based on an algorithm agreed to by the
traffic receiver. traffic receiver.
Network-layer Traffic Control Mechanisms
The traffic receiver keeps track of the sequence numbers on a The traffic receiver keeps track of the sequence numbers on a
per stream basis. In addition to number of received packets, per stream basis. In addition to number of received packets,
the traffic receiver may also report number of in-sequence the traffic receiver may also report number of in-sequence
packets, number of out-sequence packets, number of duplicate packets, number of out-sequence packets, number of duplicate
packets, and number of reordered packets. packets, and number of reordered packets.
The recommended algorithm to use to change the sequence The recommended algorithm to use to change the sequence
number on sequential packets is an incrementing value. number on sequential packets is an incrementing value.
Measurement units: Measurement units:
skipping to change at page 14, line 4 skipping to change at page 14, line 53
N-octets packets per second N-octets packets per second
See Also: See Also:
Offered Vector Offered Vector
Expected Forwarding Vector Expected Forwarding Vector
Expected Loss Vector Expected Loss Vector
Expected Sequence Vector Expected Sequence Vector
Expected Delay Vector Expected Delay Vector
Expected Jitter Vector Expected Jitter Vector
Forwarding Vector Forwarding Vector
Network-layer Traffic Control Mechanisms
Loss Vector Loss Vector
Network-layer Traffic Control Mechanisms
3.4.2 Offered Vector 3.4.2 Offered Vector
Definition: Definition:
A vector describing the measured rate at which packets having A vector describing the measured rate at which packets having
a specific DSCP or IP precedence value are offered to the a specific DSCP or IP precedence value are offered to the
DUT/SUT. DUT/SUT.
Discussion: Discussion:
Offered loads across the different code-point classes, Offered loads across the different code-point classes,
skipping to change at page 15, line 46 skipping to change at page 16, line 46
Percentage of intended packets that are expected to be Percentage of intended packets that are expected to be
dropped. dropped.
See Also: See Also:
Intended Vector Intended Vector
Offered Vector Offered Vector
Expected Forwarding Vector Expected Forwarding Vector
Expected Sequence Vector Expected Sequence Vector
Expected Delay Vector Expected Delay Vector
Expected Jitter Vector Expected Jitter Vector
One-way Packet Loss Metric [Ka99]
3.2.3.3 Expected Sequence Vector 3.2.3.3 Expected Sequence Vector
Definition: Definition:
Network-layer Traffic Control Mechanisms
A vector describing the expected in-sequence packets having a A vector describing the expected in-sequence packets having a
specific DSCP or IP precedence value. The value is dependent specific DSCP or IP precedence value. The value is dependent
on the set of offered vectors and configuration of the DUT. on the set of offered vectors and configuration of the DUT.
Network-layer Traffic Control Mechanisms
Discussion: Discussion:
The DUT is configured in a certain way in order that service The DUT is configured in a certain way in order that service
differentiation occurs for a particular DSCP or IP precedence differentiation occurs for a particular DSCP or IP precedence
value when a specific traffic mix consisting of multiple value when a specific traffic mix consisting of multiple
DSCPs or IP precedence values are applied. This term attempts DSCPs or IP precedence values are applied. This term attempts
to capture the expected forwarding behavior when subjected to to capture the expected forwarding behavior when subjected to
a certain offered vectors. a certain offered vectors.
The actual algorithm or mechanism the DUT uses to achieve The actual algorithm or mechanism the DUT uses to achieve
service differentiation is not important in describing the service differentiation is not important in describing the
skipping to change at page 16, line 57 skipping to change at page 18, line 5
to capture the expected forwarding behavior when subjected to to capture the expected forwarding behavior when subjected to
a certain offered vectors. a certain offered vectors.
The actual algorithm or mechanism the DUT uses to achieve The actual algorithm or mechanism the DUT uses to achieve
service differentiation is not important in describing the service differentiation is not important in describing the
expected delay vector. expected delay vector.
Measurement units: Measurement units:
Seconds. Seconds.
See Also:
Network-layer Traffic Control Mechanisms Network-layer Traffic Control Mechanisms
See Also:
Intended Vector Intended Vector
Offered Vector Offered Vector
Output Vectors Output Vectors
Expected Loss Vector Expected Loss Vector
Expected Sequence Vector Expected Sequence Vector
Expected Forwarding Vector Expected Forwarding Vector
Expected Jitter Vector Expected Jitter Vector
3.4.3.5 Expected Average Delay Vector 3.4.3.5 Expected Average Delay Vector
skipping to change at page 17, line 55 skipping to change at page 19, line 5
Expected Jitter Vector Expected Jitter Vector
3.4.3.6 Expected Maximum Delay Vector 3.4.3.6 Expected Maximum Delay Vector
Definition: Definition:
A vector describing the expected maximum delay for packets A vector describing the expected maximum delay for packets
having a specific DSCP or IP precedence value. The value is having a specific DSCP or IP precedence value. The value is
dependent on the set of offered vectors and configuration of dependent on the set of offered vectors and configuration of
the DUT. the DUT.
Network-layer Traffic Control Mechanisms
Discussion: Discussion:
The DUT is configured in a certain way in order that service The DUT is configured in a certain way in order that service
differentiation occurs for a particular DSCP or IP precedence differentiation occurs for a particular DSCP or IP precedence
Network-layer Traffic Control Mechanisms
value when a specific traffic mix consisting of multiple value when a specific traffic mix consisting of multiple
DSCPs or IP precedence values are applied. This term attempts DSCPs or IP precedence values are applied. This term attempts
to capture the expected forwarding behavior when subjected to to capture the expected forwarding behavior when subjected to
a certain offered vectors. a certain offered vectors.
The actual algorithm or mechanism the DUT uses to achieve The actual algorithm or mechanism the DUT uses to achieve
service differentiation is not important in describing the service differentiation is not important in describing the
expected maximum delay vector. expected maximum delay vector.
Measurement units: Measurement units:
skipping to change at page 18, line 50 skipping to change at page 20, line 5
to capture the expected forwarding behavior when subjected to to capture the expected forwarding behavior when subjected to
a certain offered vectors. a certain offered vectors.
The actual algorithm or mechanism the DUT uses to achieve The actual algorithm or mechanism the DUT uses to achieve
service differentiation is not important in describing the service differentiation is not important in describing the
expected minimum delay vector. expected minimum delay vector.
Measurement units: Measurement units:
Seconds. Seconds.
Network-layer Traffic Control Mechanisms
See Also: See Also:
Intended Vector Intended Vector
Offered Vector Offered Vector
Output Vectors Output Vectors
Expected Loss Vector Expected Loss Vector
Expected Sequence Vector Expected Sequence Vector
Expected Forwarding Vector Expected Forwarding Vector
Network-layer Traffic Control Mechanisms
Expected Jitter Vector Expected Jitter Vector
3.2.3.8 Expected Instantaneous Jitter Vector 3.2.3.8 Expected Instantaneous Jitter Vector
Definition: Definition:
A vector describing the expected jitter between two A vector describing the expected jitter between two
consecutive packets' arrival times having a specific DSCP or consecutive packets' arrival times having a specific DSCP or
IP precedence value. The value is dependent on the set of IP precedence value. The value is dependent on the set of
offered vectors and configuration of the DUT. offered vectors and configuration of the DUT.
skipping to change at page 19, line 42 skipping to change at page 21, line 4
Seconds Seconds
See Also: See Also:
Delay Delay
Jitter Jitter
Offered Vector Offered Vector
Output Vectors Output Vectors
Expected Average Jitter Vector Expected Average Jitter Vector
Expected Peak-to-peak Jitter Vector Expected Peak-to-peak Jitter Vector
Stream Stream
Network-layer Traffic Control Mechanisms
3.2.3.9 Expected Average Jitter Vector 3.2.3.9 Expected Average Jitter Vector
Definition: Definition:
A vector describing the expected jitter in packet arrival A vector describing the expected jitter in packet arrival
times for packets having specific DSCP or IP precedence times for packets having specific DSCP or IP precedence
value. The value is dependent on the set of offered vectors value. The value is dependent on the set of offered vectors
and configuration of the DUT. and configuration of the DUT.
Discussion: Discussion:
Average Jitter Vector is the average of all the Instantaneous Average Jitter Vector is the average of all the Instantaneous
Jitter Vectors measured during the test duration for the same Jitter Vectors measured during the test duration for the same
DSCP or IP precedence value. DSCP or IP precedence value.
Network-layer Traffic Control Mechanisms
Measurement units: Measurement units:
Seconds Seconds
See Also: See Also:
Intended Vector Intended Vector
Offered Vector Offered Vector
Output Vectors Output Vectors
Expected Instantaneous Jitter Vector Expected Instantaneous Jitter Vector
Expected Peak-to-peak Jitter Vector Expected Peak-to-peak Jitter Vector
skipping to change at page 20, line 44 skipping to change at page 22, line 4
Measurement units: Measurement units:
Seconds Seconds
See Also: See Also:
Intended Vector Intended Vector
Offered Vector Offered Vector
Output Vectors Output Vectors
Expected Instantaneous Jitter Vector Expected Instantaneous Jitter Vector
Expected Average Jitter Vector Expected Average Jitter Vector
Network-layer Traffic Control Mechanisms
3.4.4 Output Vectors 3.4.4 Output Vectors
3.4.4.1 Forwarding Vector 3.4.4.1 Forwarding Vector
Network-layer Traffic Control Mechanisms
Definition: Definition:
The number of packets per second for all packets containing a The number of packets per second for all packets containing a
specific DSCP or IP precedence value that a device can be specific DSCP or IP precedence value that a device can be
observed to successfully forward to the correct destination observed to successfully forward to the correct destination
interface in response to an offered vector. interface in response to an offered vector.
Discussion: Discussion:
Forwarding Vector is expressed as pair of numbers. Both the Forwarding Vector is expressed as pair of numbers. Both the
specific DSCP (or IP precedence) value AND the packets per specific DSCP (or IP precedence) value AND the packets per
skipping to change at page 21, line 51 skipping to change at page 23, line 5
The percentage of packets containing specific DSCP or IP The percentage of packets containing specific DSCP or IP
precedence value that a DUT/SUT did not transmit to the precedence value that a DUT/SUT did not transmit to the
correct destination interface in response to an offered correct destination interface in response to an offered
vector. vector.
Discussion: Discussion:
Loss Vector is expressed as pair of numbers. Both the Loss Vector is expressed as pair of numbers. Both the
specific DSCP (or IP precedence) value AND the percentage specific DSCP (or IP precedence) value AND the percentage
value combine to make a vector. value combine to make a vector.
Network-layer Traffic Control Mechanisms
The Loss Vector represents percentage based on a specific The Loss Vector represents percentage based on a specific
DSCP or IP precedence value. It is not necessarily based on DSCP or IP precedence value. It is not necessarily based on
a stream or flow. The Loss Vector may be expressed as per a stream or flow. The Loss Vector may be expressed as per
port of the DUT/SUT. However, it must be consistent with the port of the DUT/SUT. However, it must be consistent with the
Expected Loss Vector Expected Loss Vector
Network-layer Traffic Control Mechanisms
Loss Vector is a per-hop measurement. The DUT/SUT may change Loss Vector is a per-hop measurement. The DUT/SUT may change
the specific DSCP or IP precedence value for a multiple-hop the specific DSCP or IP precedence value for a multiple-hop
measurement. measurement.
Measurement Units: Measurement Units:
Percentage of offered packets that are not forwarded. Percentage of offered packets that are not forwarded.
See Also: See Also:
Intended Vector Intended Vector
Offered Vector Offered Vector
Expected Vectors Expected Vectors
Forwarding Vector Forwarding Vector
Sequence Vector Sequence Vector
Delay Vectors Delay Vectors
One-way Packet Loss Metric [Ka99]
3.4.4.3 Sequence Vector 3.4.4.3 Sequence Vector
Definition: Definition:
The number of packets per second for all packets containing a The number of packets per second for all packets containing a
specific DSCP or IP precedence value that a device can be specific DSCP or IP precedence value that a device can be
observed to transmit in sequence to the correct destination observed to transmit in sequence to the correct destination
interface in response to an offered vector. interface in response to an offered vector.
Discussion: Discussion:
skipping to change at page 22, line 49 skipping to change at page 24, line 5
Sequence Vector is a per-hop measurement. The DUT/SUT may Sequence Vector is a per-hop measurement. The DUT/SUT may
change the specific DSCP or IP precedence value for a change the specific DSCP or IP precedence value for a
multiple-hop measurement. multiple-hop measurement.
Measurement Units: Measurement Units:
N-octet packets per second N-octet packets per second
Issues: Issues:
Network-layer Traffic Control Mechanisms
See Also: See Also:
In-sequence Packet In-sequence Packet
Intended Vector Intended Vector
Offered Vector Offered Vector
Expected Vectors Expected Vectors
Loss Vector Loss Vector
Forwarding Vector Forwarding Vector
Network-layer Traffic Control Mechanisms
Delay Vectors Delay Vectors
3.4.4.4 Instantaneous Delay Vector 3.4.4.4 Instantaneous Delay Vector
Definition: Definition:
The delay for a packet containing specific DSCP or IP The delay for a packet containing specific DSCP or IP
precedence value that a device can be observed to precedence value that a device can be observed to
successfully transmit to the correct destination interface in successfully transmit to the correct destination interface in
response to an offered vector. response to an offered vector.
skipping to change at page 23, line 51 skipping to change at page 25, line 4
Seconds Seconds
See Also: See Also:
Delay Delay
Intended Vector Intended Vector
Offered Vector Offered Vector
Expected Delay Vectors Expected Delay Vectors
Average Delay Vector Average Delay Vector
Maximum Delay Vector Maximum Delay Vector
Minimum Delay Vector Minimum Delay Vector
Network-layer Traffic Control Mechanisms
3.4.4.5 Average Delay Vector 3.4.4.5 Average Delay Vector
Definition: Definition:
Network-layer Traffic Control Mechanisms
The average delay for packets containing specific DSCP or IP The average delay for packets containing specific DSCP or IP
precedence value that a device can be observed to precedence value that a device can be observed to
successfully transmit to the correct destination interface in successfully transmit to the correct destination interface in
response to an offered vector. response to an offered vector.
Discussion: Discussion:
Average Delay vector is expressed as pair of numbers. Both Average Delay vector is expressed as pair of numbers. Both
the specific DSCP (or IP precedence) value AND delay value the specific DSCP (or IP precedence) value AND delay value
combine to make a vector. combine to make a vector.
skipping to change at page 24, line 46 skipping to change at page 26, line 4
Seconds Seconds
See Also: See Also:
Delay Delay
Intended Vector Intended Vector
Offered Vector Offered Vector
Expected Delay Vectors Expected Delay Vectors
Instantaneous Delay Vector Instantaneous Delay Vector
Maximum Delay Vector Maximum Delay Vector
Minimum Delay Vector Minimum Delay Vector
Network-layer Traffic Control Mechanisms
3.4.4.6 Maximum Delay Vector 3.4.4.6 Maximum Delay Vector
Definition: Definition:
The maximum delay from all packets containing specific DSCP The maximum delay from all packets containing specific DSCP
or IP precedence value that a device can be observed to or IP precedence value that a device can be observed to
successfully transmit to the correct destination interface in successfully transmit to the correct destination interface in
response to an offered vector. response to an offered vector.
Discussion: Discussion:
Network-layer Traffic Control Mechanisms
Maximum Delay vector is expressed as pair of numbers. Both Maximum Delay vector is expressed as pair of numbers. Both
the specific DSCP (or IP precedence) value AND delay value the specific DSCP (or IP precedence) value AND delay value
combine to make a vector. combine to make a vector.
The Maximum Delay Vector represents delay on its specific The Maximum Delay Vector represents delay on its specific
DSCP or IP precedence value. It is not necessarily based on DSCP or IP precedence value. It is not necessarily based on
a stream or flow. The Maximum Delay vector may be expressed a stream or flow. The Maximum Delay vector may be expressed
as per port of the DUT/SUT. However, it must be consistent as per port of the DUT/SUT. However, it must be consistent
with the Expected Delay vector. with the Expected Delay vector.
skipping to change at page 25, line 50 skipping to change at page 27, line 5
The minimum delay from all packets containing specific DSCP The minimum delay from all packets containing specific DSCP
or IP precedence value that a device can be observed to or IP precedence value that a device can be observed to
successfully transmit to the correct destination interface in successfully transmit to the correct destination interface in
response to an offered vector. response to an offered vector.
Discussion: Discussion:
Delay vector is expressed as pair of numbers. Both the Delay vector is expressed as pair of numbers. Both the
specific DSCP (or IP precedence) value AND delay value specific DSCP (or IP precedence) value AND delay value
combine to make a vector. combine to make a vector.
Network-layer Traffic Control Mechanisms
The Minimum Delay Vector represents delay on its specific The Minimum Delay Vector represents delay on its specific
DSCP or IP precedence value. It is not necessarily based on DSCP or IP precedence value. It is not necessarily based on
a stream or flow. The Minimum Delay vector may be expressed a stream or flow. The Minimum Delay vector may be expressed
as per port of the DUT/SUT. However, it must be consistent as per port of the DUT/SUT. However, it must be consistent
with the Expected Delay vector. with the Expected Delay vector.
Minimum Delay Vector is based upon the minimum Instantaneous Minimum Delay Vector is based upon the minimum Instantaneous
Delay Vector of all packets in a Forwarding Vector. Delay Vector of all packets in a Forwarding Vector.
Network-layer Traffic Control Mechanisms
Minimum Delay Vector is a per-hop measurement. The DUT/SUT Minimum Delay Vector is a per-hop measurement. The DUT/SUT
may change the specific DSCP or IP precedence value for a may change the specific DSCP or IP precedence value for a
multiple-hop measurement. multiple-hop measurement.
Minimum Delay vector can be obtained at any offered load. Minimum Delay vector can be obtained at any offered load.
Recommend at or below the channel capacity in the absence of Recommend at or below the channel capacity in the absence of
congestion. For congested delay, run the offered load above congestion. For congested delay, run the offered load above
the channel capacity. the channel capacity.
Measurement Units: Measurement Units:
skipping to change at page 26, line 46 skipping to change at page 28, line 5
Discussion: Discussion:
Instantaneous Jitter is the absolute value of the difference Instantaneous Jitter is the absolute value of the difference
between the delay measurement of two packets belonging to the between the delay measurement of two packets belonging to the
same stream. same stream.
Jitter vector is expressed as pair of numbers. Both the Jitter vector is expressed as pair of numbers. Both the
specific DSCP (or IP precedence) value AND jitter value specific DSCP (or IP precedence) value AND jitter value
combine to make a vector. combine to make a vector.
Network-layer Traffic Control Mechanisms
The delay fluctuation between two consecutive packets in a The delay fluctuation between two consecutive packets in a
stream is reported as the "Instantaneous Jitter". stream is reported as the "Instantaneous Jitter".
Instantaneous Jitter Vector can be expressed as |D(i) - D(i- Instantaneous Jitter Vector can be expressed as |D(i) - D(i-
1)| where D equals the delay and i is the test sequence 1)| where D equals the delay and i is the test sequence
number. Packets lost are not counted in the measurement. number. Packets lost are not counted in the measurement.
Instantaneous Jitter Vector is a per-hop measurement. The Instantaneous Jitter Vector is a per-hop measurement. The
DUT/SUT may change the specific DSCP or IP precedence value DUT/SUT may change the specific DSCP or IP precedence value
for a multiple-hop measurement. for a multiple-hop measurement.
Network-layer Traffic Control Mechanisms
Forwarding Vector may contain several Instantaneous Jitter Forwarding Vector may contain several Instantaneous Jitter
Vectors. For n packets received in a Forwarding Vector, Vectors. For n packets received in a Forwarding Vector,
there are exactly (n-1) Instantaneous Jitter Vectors. there are exactly (n-1) Instantaneous Jitter Vectors.
Measurement units: Measurement units:
Seconds Seconds
See Also: See Also:
Delay Delay
Jitter Jitter
skipping to change at page 27, line 46 skipping to change at page 29, line 4
Average Jitter vector is expressed as pair of numbers. Both Average Jitter vector is expressed as pair of numbers. Both
the specific DSCP (or IP precedence) value AND jitter value the specific DSCP (or IP precedence) value AND jitter value
combine to make a vector. combine to make a vector.
Average Jitter vector is a per-hop measurement. The DUT/SUT Average Jitter vector is a per-hop measurement. The DUT/SUT
may change the specific DSCP or IP precedence value for a may change the specific DSCP or IP precedence value for a
multiple-hop measurement. multiple-hop measurement.
Measurement units: Measurement units:
Seconds Seconds
Network-layer Traffic Control Mechanisms
See Also: See Also:
Jitter Jitter
Forwarding Vector Forwarding Vector
Stream Stream
Expected Vectors Expected Vectors
Instantaneous Jitter Vector Instantaneous Jitter Vector
Peak-to-peak Jitter Vector Peak-to-peak Jitter Vector
3.4.4.10 Peak-to-peak Jitter Vector 3.4.4.10 Peak-to-peak Jitter Vector
Network-layer Traffic Control Mechanisms
Definition: Definition:
The maximum possible variation in the delay for packets The maximum possible variation in the delay for packets
containing specific DSCP or IP precedence value that a device containing specific DSCP or IP precedence value that a device
can be observed to successfully transmit to the correct can be observed to successfully transmit to the correct
destination interface in response to an offered vector. destination interface in response to an offered vector.
Discussion: Discussion:
Peak-to-peak Jitter Vector is the maximum delay minus the Peak-to-peak Jitter Vector is the maximum delay minus the
minimum delay of the packets (in a vector) forwarded by the minimum delay of the packets (in a vector) forwarded by the
skipping to change at page 29, line 18 skipping to change at page 30, line 18
Documents of this type do not directly affect the security of Documents of this type do not directly affect the security of
the Internet or of corporate networks as long as benchmarking the Internet or of corporate networks as long as benchmarking
is not performed on devices or systems connected to is not performed on devices or systems connected to
production networks. production networks.
Packets with unintended and/or unauthorized DSCP or IP Packets with unintended and/or unauthorized DSCP or IP
precedence values may present security issues. Determining precedence values may present security issues. Determining
the security consequences of such packets is out of scope for the security consequences of such packets is out of scope for
this document. this document.
5. References 5. Normative References
[1] Bradner, S., Editor, "Benchmarking Terminology for [Br91] Bradner, S., Editor, "Benchmarking Terminology for
Network Interconnection Devices", RFC 1242, July 1991. Network Interconnection Devices", RFC 1242, July 1991.
[2] Mandeville, R., "Benchmarking Terminology for LAN [Ma98] Mandeville, R., "Benchmarking Terminology for LAN
Switching Devices", RFC 2285, February 1998. Switching Devices", RFC 2285, February 1998.
[3] K. Nichols, S. Blake, F. Baker, D. Black,"Definition of [Ni98] K. Nichols, S. Blake, F. Baker, D. Black,"Definition of
the Differentiated Services Field (DS Field) in the IPv4 the Differentiated Services Field (DS Field) in the IPv4
and IPv6 Headers", RFC 2474, December 1998. and IPv6 Headers", RFC 2474, December 1998.
[4] S. Blake, D. Black, M. Carlson, E. Davies, Z. Wang, W. Network-layer Traffic Control Mechanisms
Weiss, "An Architecture for Differentiated Services", RFC
2475, December 1998.
[5] V. Jacobson, K. Nichols, K. Poduri, _An Expedited 6. Informative References
[Al99] Almes, G., Kalidindi, S., Zekauskas, M., _A One-way Delay
Metric for IPPM_, RFC 2679, September 1999
[Bl98] S. Blake, D. Black, M. Carlson, E. Davies, Z. Wang, W.
Weiss, "An Architecture for Differentiated Services",
RFC 2475, December 1998.
[Br99] Bradner, S., McQuaid, J. _Benchmarking Methodology for
Network Interconnect Devices_, RFC 2544, March 1999
[De02] C. Demichelis, P. Chimento, _IP Packet Delay Variation
Metric for IPPM_, RFC 3393, November 2002
[Ja99] V. Jacobson, K. Nichols, K. Poduri, _An Expedited
Forwarding PHB_, RFC 2598, June 1999 Forwarding PHB_, RFC 2598, June 1999
[6] C. Demichelis, P. Chimento, _IP Packet Delay Variation [Ka99] Almes, G., Kalidindi, S., Zekauskas, M., _A One-way
Metric for IPPM_, draft-ietf-ippm-ipdv-10.txt Packet Loss Metric for IPPM_, RFC 2680, September 1999
[7] H. Schulzrinne, GMD Fokus, S. Casner, R. Frederick, [Ma91] A. Mankin, K. Ramakrishnan, _Gateway Congestion Control
Survey_, RFC 1254, August 1991
[Na84] Nagle, John, "Congestion Control in IP/TCP
Internetworks", RFC 896, January 1984.
[Ra99] Ramakrishnan, K. and Floyd, S., "A Proposal to add
Explicit Congestion Notification (ECN) to IP", RFC 2481,
January 1999.
[Sc96] H. Schulzrinne, GMD Fokus, S. Casner, R. Frederick,
V. Jacobson, _RTP: A Transport Protocol for Real-Time V. Jacobson, _RTP: A Transport Protocol for Real-Time
Applications_, RFC 1889, January 1996 Applications_, RFC 1889, January 1996
[8] A. Mankin, K. Ramakrishnan, _Gateway Congestion Control
Survey_, RFC 1254, August 1991
Network-layer Traffic Control Mechanisms Network-layer Traffic Control Mechanisms
6. Authors' Address 7. Authors' Address
Jerry Perser Jerry Perser
Spirent Communications Spirent Communications
26750 Agoura Road 26750 Agoura Road
Calabasas, CA 91302 Calabasas, CA 91302
USA USA
Phone: + 1 818 676 2300 Phone: + 1 818 676 2300
EMail: jerry.perser@spirentcom.com EMail: jerry.perser@spirentcom.com
skipping to change at page 31, line 6 skipping to change at page 33, line 6
Scott Poretsky Scott Poretsky
Avici Systems Avici Systems
101 Billerica Ave_Building #6 101 Billerica Ave_Building #6
N. Billerica, MA 01862 N. Billerica, MA 01862
USA USA
Phone: + 1 978 964 2287 Phone: + 1 978 964 2287
EMail: sporetsky@avici.com EMail: sporetsky@avici.com
Network-layer Traffic Control Mechanisms Network-layer Traffic Control Mechanisms
7. Full Copyright Statement 8. Full Copyright Statement
Copyright (C) The Internet Society (1998). All Rights Copyright (C) The Internet Society (1998). All Rights
Reserved. Reserved.
This document and translations of it may be copied and This document and translations of it may be copied and
furnished to others, and derivative works that comment on or furnished to others, and derivative works that comment on or
otherwise explain it or assist in its implementation may be otherwise explain it or assist in its implementation may be
prepared, copied, published and distributed, in whole or in prepared, copied, published and distributed, in whole or in
part, without restriction of any kind, provided that the part, without restriction of any kind, provided that the
above copyright notice and this paragraph are included on all above copyright notice and this paragraph are included on all
 End of changes. 

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