draft-ietf-bmwg-mcast-03.txt   draft-ietf-bmwg-mcast-04.txt 
Network Working Group K. Dubray Network Working Group K. Dubray
INTERNET-DRAFT Bay Networks INTERNET-DRAFT IronBridge Networks
Expiration Date: September 1998 March 1998 Expiration Date: January 1999 July 1998
Terminology for IP Multicast Benchmarking Terminology for IP Multicast Benchmarking
<draft-ietf-bmwg-mcast-03.txt> <draft-ietf-bmwg-mcast-04.txt>
Status of this Memo Status of this Memo
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Abstract Abstract
The purpose of this draft is to add terminology specific to the The purpose of this draft is to define terminology specific to the
benchmarking of multicast IP forwarding devices. It builds upon the benchmarking of multicast IP forwarding devices. It builds upon the
tenets set forth in RFC 1242, RFC 1944, and other IETF Benchmarking tenets set forth in RFC 1242, RFC 2285, and other IETF Benchmarking
Methodology Working Group (BMWG) effort and extends them to the Methodology Working Group (BMWG) efforts. This document seeks to
multicast paradigm. extend these efforts to the multicast paradigm.
1. Introduction 1. Introduction
Network forwarding devices are being required to take a single Network forwarding devices are being required to take a single frame
frame and support delivery to a number of destinations having and support delivery to a number of destinations having membership to
membership to a particular group. As such, multicast support may a particular group. As such, multicast support may place a different
place a different burden on the resources of these network burden on the resources of these network forwarding devices than with
forwarding devices than with unicast or broadcast traffic types. unicast or broadcast traffic types.
By clearly identifying benchmarks and related terminology in this Such burdens may not be readily apparent at first glance - the IP
document, it is hoped that detailed methodologies can be generated multicast packet's Class D address may be the only noticeable
in subsequent documents. Taken in tandem, these two efforts difference from an IP unicast packet. However, there are many
endeavor to assist the clinical, empirical, and consistent factors that may impact the treatment of IP multicast packets.
Consider how a device's architecture may impact the handling of a
multicast frame. For example, is the multicast packet subject to the
same processing as its unicast analog? Or is the multicast packet
treated as an exeception and processed on a different data path?
Consider, too, how a shared memory architecture may demonstrate a
different performance profile than an architecture which explicitly
passes each individual packet between the processing entities.
In addition to forwarding device architecture, there are other
factors that may impact a device's or system's multicast related
performance. Protocol requirements may demand that routers and
switches consider destination and source addressing in its multicast
forwarding decisions. Capturing multicast source/destination
addressing information may impact forwarding table size and lengthen
lookups. Topological factors such as the degree of packet
replication, the number of multicast groups being supported by the
system, or the placement of multicast packets in unicast wrappers to
span non-multicast network paths may all potentially affect a
system's multicast related performance. For an overall understanding
of IP multicasting, the reader is directed to [Se98], [Hu95], and
[Mt98].
By clearly identifying IP multicast benchmarks and related
terminology in this document, it is hoped that detailed methodologies
can be generated in subsequent documents. Taken in tandem, these two
efforts endeavor to assist the clinical, empirical, and consistent
characterization of certain aspects of multicast technologies and characterization of certain aspects of multicast technologies and
their individual implementations. their individual implementations. Understanding the operational
profile of multicast forwarding devices may assist the network
designer to better deploy multicast in his or her networking
environment.
[While primarily directed towards intermediate IP multicast This work is primarily directed towards intermediate IP multicast
forwarding devices on LANs, elements of this text may or may not be forwarding devices (e.g., routers or switches) on LANs. Elements of
applicable to other media as well.] this text may or may not be applicable to other media as well.
Moreover, this document focuses on one source to many destinations
profiling. Elements of this document may require extension when
considering multiple source to multiple destination IP multicast
communication.
2. Definition Format 2. Definition Format
This section cites the template suggested by RFC 1242 in the This section cites the template suggested by RFC 1242 in the
specification of a term to be defined. specification of a term to be defined.
Term to be defined. Term to be defined.
Definition: Definition:
The specific definition for the term. The specific definition for the term.
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[Issues:] [Issues:]
List of issues or conditions that effect this term. This List of issues or conditions that effect this term. This
field is optional in this draft. field is optional in this draft.
[See Also:] [See Also:]
List of other terms that are relevant to the discussion List of other terms that are relevant to the discussion
of this term. This field is optional in this draft. of this term. This field is optional in this draft.
2.1 Existing Terminology 2.1 Existing Terminology
This document draws on existing terminology defined in other This document draws on existing terminology defined in other BMWG
BMWG work. Examples include, but are not limited to: work. Examples include, but are not limited to:
Throughput (RFC 1242, section 3.17) Throughput (RFC 1242, section 3.17)
Latency (RFC 1242, section 3.8) Latency (RFC 1242, section 3.8)
Constant Load (RFC 1242, section 3.4) Constant Load (RFC 1242, section 3.4)
Frame Loss Rate (RFC 1242, section 3.6) Frame Loss Rate (RFC 1242, section 3.6)
Overhead behavior (RFC 1242, section 3.11) Overhead behavior (RFC 1242, section 3.11)
Forwarding Rates ([4], section 3.6) Forwarding Rates (RFC 2285, section 3.6)
Loads ([4], section 3.5) Loads (RFC 2285, section 3.5)
Devices ([4], section 3.1) Devices (RFC 2285, section 3.1)
3. Table of Defined Terms 3. Table of Defined Terms
3.1 General Nomenclature 3.1 General Nomenclature
3.1.1 Traffic Class. 3.1.1 Traffic Class.
3.1.2 Group Class. 3.1.2 Group Class.
3.1.3 Service Class. 3.1.3 Service Class.
3.2 Forwarding and Throughput 3.2 Forwarding and Throughput
3.2.1 Mixed Class Throughput (MCT). 3.2.1 Mixed Class Throughput (MCT).
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3.4.1 Group Join Delay. 3.4.1 Group Join Delay.
3.4.2 Group Leave Delay. 3.4.2 Group Leave Delay.
3.5 Capacity 3.5 Capacity
3.5.1 Multicast Group Capacity. 3.5.1 Multicast Group Capacity.
3.6 Interaction 3.6 Interaction
3.6.1 Burdened Response 3.6.1 Burdened Response
3.6.2 Forwarding Burdened Multicast Latency 3.6.2 Forwarding Burdened Multicast Latency
3.6.3 Forwarding Burdened Join Delay 3.6.3 Forwarding Burdened Join Delay
3.6.4 Forwarding Burdened Multicast Group Capacity.
3.1 General Nomenclature 3.1 General Nomenclature
This section will present general terminology to be used in This section will present general terminology to be used in
this and other documents. this and other documents.
3.1.1 Traffic Class. 3.1.1 Traffic Class.
Definition: Definition:
An equivalence class of packets comprising one or more data An equivalence class of packets comprising one or more data
streams. streams.
Discussion: Discussion:
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Definition: Definition:
An equivalence class of packets comprising one or more data An equivalence class of packets comprising one or more data
streams. streams.
Discussion: Discussion:
In the scope of this document, Traffic Class will be considered In the scope of this document, Traffic Class will be considered
a logical identifier used to discriminate between a set or sets a logical identifier used to discriminate between a set or sets
of packets offered the DUT. of packets offered the DUT.
For example, one Traffic Class may identify a set of unicast packets For example, one Traffic Class may identify a set of unicast
packets
offered to the DUT. Another Traffic Class may differentiate the offered to the DUT. Another Traffic Class may differentiate the
multicast packets destined to multicast group X. Yet another multicast packets destined to multicast group X. Yet another
Class may distinguish the set of multicast packets destined to Class may distinguish the set of multicast packets destined to
multicast group Y. multicast group Y.
Unless otherwise qualified, the usage of the word "Class" in this Unless otherwise qualified, the usage of the word "Class" in this
document will refer simply to a Traffic Class. document will refer simply to a Traffic Class.
Measurement units: Measurement units:
Not applicable. Not applicable.
3.1.2 Group Class. 3.1.2 Group Class.
Definition: Definition:
A specific type of Traffic Class where the packets comprising the Class
A specific type of Traffic Class where the packets comprising the
Class
are destined to a particular multicast group. are destined to a particular multicast group.
Discussion: Discussion:
Measurement units: Measurement units:
Not applicable. Not applicable.
3.1.3 Service Class. 3.1.3 Service Class.
Definition: Definition:
A specific type of Traffic Class where the packets comprising the Class A specific type of Traffic Class where the packets comprising the
Class
require particular treatment or treatments by the network require particular treatment or treatments by the network
forwarding devices along the path to the packets' destination(s). forwarding devices along the path to the packets' destination(s).
Discussion: Discussion:
Measurement units: Measurement units:
Not applicable. Not applicable.
3.2 Forwarding and Throughput. 3.2 Forwarding and Throughput.
This section presents terminology relating to the characterization of This section presents terminology related to the characterization of
the packet forwarding ability of a DUT/SUT in a multicast environment. the packet forwarding ability of a DUT/SUT in a multicast
environment.
Some metrics extend the concept of throughput presented in RFC 1242. Some metrics extend the concept of throughput presented in RFC 1242.
The notion of Forwarding Rate is cited in RFC 2285.
3.2.1 Mixed Class Throughput (MCT). 3.2.1 Mixed Class Throughput (MCT).
Definition: Definition:
The maximum rate at which none of the offered frames, comprised The maximum rate at which none of the offered frames, comprised
from a unicast Class and a multicast Class, to be forwarded are from a unicast Class and a multicast Class, to be forwarded are
dropped by the device across a fixed number of ports. dropped by the device across a fixed number of ports.
Discussion: Discussion:
Often times, throughput is collected on a homogenous traffic Often times, throughput is collected on a homogenous traffic
type - though the packets' destinations may vary, the packets class - the offered load to the DUT is either singularly unicast or
follow the same packet forwarding path through the DUT. singularly multicast. In most networking environments, the traffic
mix is seldom so uniformly distributed.
Based on the RFC 1242 definition for throughput, the Mixed Based on the RFC 1242 definition for throughput, the Mixed
Class Throughput benchmark attempts to characterize the DUT's Class Throughput benchmark attempts to characterize the DUT's
ability to process both unicast and multicast frames in the ability to process both unicast and multicast frames in the
same aggregated traffic stream. same aggregated traffic stream.
Measurement units: Measurement units:
Frames per second Frames per second
Issues: Issues:
Related methodology may have to address the ratio of unicast packets Related methodology may have to address the ratio of unicast
packets
to multicast packets. to multicast packets.
3.2.2 Scaled Group Forwarding Matrix (SGFM). 3.2.2 Scaled Group Forwarding Matrix (SGFM).
Definition: Definition:
A table that demonstrates Forwarding Rate as a function of A table that demonstrates Forwarding Rate as a function of
tested multicast groups for a fixed number of tested tested multicast groups for a fixed number of tested
DUT/SUT ports. DUT/SUT ports.
Discussion: Discussion:
A desirable attribute of many Internet mechanisms is the ability A desirable attribute of many Internet mechanisms is the ability
to "scale." This benchmark seeks to demonstrate the ability to "scale." This benchmark seeks to demonstrate the ability
of a SUT to forward as the number of multicast groups is scaled of a SUT to forward as the number of multicast groups is scaled
upwards. upwards.
Measurement units: Measurement units:
Packets per second, with corresponding tested multicast group Packets per second, with corresponding tested multicast group
and port configurations. and port configurations.
Issues: Issues:
The corresponding methodology (or even the definition itself) may The corresponding methodology may have to reflect the impact
have to reflect the impact that the pairing (source, group) has on that the pairing (source, group) has on many multicast routing
many multicast routing protocols. protocols.
Refers to the concept of Forwarding Rate originally defined in
this document. The definition of Forwarding Rate has been
moved to [4].
3.2.3 Aggregated Multicast Throughput (AMT) 3.2.3 Aggregated Multicast Throughput (AMT)
Definition: Definition:
The maximum rate at which none of the offered frames to be The maximum rate at which none of the offered frames to be
forwarded through N destination interfaces of the same multicast forwarded through N destination interfaces of the same multicast
group are dropped. group are dropped.
Discussion: Discussion:
Another "scaling" type of exercise, designed to identify the Another "scaling" type of exercise, designed to identify the
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and correctly forwarded by the DUT without loss. and correctly forwarded by the DUT without loss.
Discussion: Discussion:
A popular technique in presenting a frame to a device that may A popular technique in presenting a frame to a device that may
not support a protocol feature is to encapsulate, or tunnel, not support a protocol feature is to encapsulate, or tunnel,
the packet containing the unsupported feature in a format that the packet containing the unsupported feature in a format that
is supported by that device. is supported by that device.
More specifically, encapsulation refers to the act of taking a More specifically, encapsulation refers to the act of taking a
frame or part of a frame and embedding it as a payload of another frame or part of a frame and embedding it as a payload of another
frame. This benchmark attempts to characterize the overhead behavior frame. This benchmark attempts to characterize the overhead
behavior
associated with that translational process. associated with that translational process.
Consideration may need to be given with respect to the impact Consideration may need to be given with respect to the impact
of different frame formats on usable bandwidth. of different frame formats on usable bandwidth.
Measurement units: Measurement units:
Frames per second. Frames per second.
3.2.5 Decapsulation Throughput (DT) 3.2.5 Decapsulation Throughput (DT)
Definition: Definition:
The maximum rate at which frames offered a DUT are decapsulated The maximum rate at which frames offered a DUT are decapsulated
and correctly forwarded by the DUT without loss. and correctly forwarded by the DUT without loss.
Discussion: Discussion:
A popular technique in presenting a frame to a device that may A popular technique in presenting a frame to a device that may
not support a protocol feature is to encapsulate, or tunnel, not support a protocol feature is to encapsulate, or tunnel,
the packet containing the unsupported feature in a format that the packet containing the unsupported feature in a format that
is supported by that device. At some point, the frame may be required is supported by that device. At some point, the frame may be
to be returned its orginal format from its encapsulation wrapper for required
to be returned its orginal format from its encapsulation wrapper
for
use by the frame's next destination. use by the frame's next destination.
More specifically, decapsulation refers to the act of taking a More specifically, decapsulation refers to the act of taking a
frame or part of a frame embedded as a payload of another frame and frame or part of a frame embedded as a payload of another frame and
returning it to the payload's appropriate format. This benchmark returning it to the payload's appropriate format. This benchmark
attempts to characterize the overhead behavior associated with that attempts to characterize the overhead behavior associated with that
translational process. translational process.
Consideration may need to be given with respect to the impact Consideration may need to be given with respect to the impact
of different frame formats on usable bandwidth. of different frame formats on usable bandwidth.
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attempts to characterize the overhead behavior associated with that attempts to characterize the overhead behavior associated with that
translational process. translational process.
Consideration may need to be given with respect to the impact Consideration may need to be given with respect to the impact
of different frame formats on usable bandwidth. of different frame formats on usable bandwidth.
Measurement units: Measurement units:
Frames per second. Frames per second.
3.2.6 Re-encapsulation Throughput (RET) 3.2.6 Re-encapsulation Throughput (RET)
Definition: Definition:
The maximum rate at which frames of one encapsulated format offered a DUT The maximum rate at which frames of one encapsulated format offered
are converted to another encapsulated format and correctly forwarded a DUT
are converted to another encapsulated format and correctly
forwarded
by the DUT without loss. by the DUT without loss.
Discussion: Discussion:
A popular technique in presenting a frame to a device that may A popular technique in presenting a frame to a device that may
not support a protocol feature is to encapsulate, or tunnel, not support a protocol feature is to encapsulate, or tunnel,
the packet containing the unsupported feature in a format that the packet containing the unsupported feature in a format that
is supported by that device. At some point, the frame may be required is supported by that device. At some point, the frame may be
to be converted from one encapsulation format to another encapsulation required
to be converted from one encapsulation format to another
encapsulation
format. format.
More specifically, re-encapsulation refers to the act of taking an More specifically, re-encapsulation refers to the act of taking an
encapsulated payload of one format and replacing it with another encapsulated payload of one format and replacing it with another
encapsulated format - all the while preserving the original payload's encapsulated format - all the while preserving the original
payload's
contents. This benchmark attempts to characterize the overhead contents. This benchmark attempts to characterize the overhead
behavior associated with that translational process. behavior associated with that translational process.
Consideration may need to be given with respect to the impact Consideration may need to be given with respect to the impact
of different frame formats on usable bandwidth. of different frame formats on usable bandwidth.
Measurement units: Measurement units:
Frames per second. Frames per second.
3.3 Forwarding Latency. 3.3 Forwarding Latency.
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Discussion: Discussion:
This benchmark is based on the RFC 1242 definition of latency. This benchmark is based on the RFC 1242 definition of latency.
While it is useful to collect latency between a pair of source While it is useful to collect latency between a pair of source
and destination multicast ports, it may be insightful to collect and destination multicast ports, it may be insightful to collect
the same type of measurements across a range of ports supporting the same type of measurements across a range of ports supporting
that Group Class. that Group Class.
A variety of statistical exercises can be applied to the set of A variety of statistical exercises can be applied to the set of
latencies measurements. latencies measurements.
Dubray, K. Expires September 1998 [Page 7]^L
Measurement units: Measurement units:
Time units with enough precision to reflect measurement. Time units with enough precision to reflect a latency measurement.
3.3.2 Min/Max Multicast Latency. 3.3.2 Min/Max Multicast Latency.
Definition: Definition:
The difference between the maximum latency measurement and the The difference between the maximum latency measurement and the
minimum latency measurement from the set of latencies produced by minimum latency measurement from the set of latencies produced by
the Multicast Latency benchmark. the Multicast Latency benchmark.
Discussion: Discussion:
This statistic may yield some insight into how a particular This statistic may yield some insight into how a particular
implementation handles its multicast traffic. This may be useful implementation handles its multicast traffic. This may be useful
to users of multicast synchronization types of applications. to users of multicast synchronization types of applications.
Measurement units: Measurement units:
Time units with enough precision to reflect measurement. Time units with enough precision to reflect latency measurement.
3.4 Overhead 3.4 Overhead
This section presents terminology relating to the characterization of This section presents terminology relating to the characterization of
the overhead delays associated with explicit operations found in the overhead delays associated with explicit operations found in
multicast environments. multicast environments.
3.4.1 Group Join Delay. 3.4.1 Group Join Delay.
Definition: Definition:
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the number or type of multicast-related protocols configured the number or type of multicast-related protocols configured
on the system under test. Other factors are physical topology and on the system under test. Other factors are physical topology and
"tree" configuration. "tree" configuration.
Because of the number of variables that could impact this metric, Because of the number of variables that could impact this metric,
the metric may be a better characterization tool for a device or the metric may be a better characterization tool for a device or
system rather than a basis for comparisons with other devices. system rather than a basis for comparisons with other devices.
A consideration for the related methodology: possible need to A consideration for the related methodology: possible need to
differentiate a specifically-forwarded multicast frame from those differentiate a specifically-forwarded multicast frame from those
sprayed by protocols implementing a flooding tactic to solicit prune sprayed by protocols implementing a flooding tactic to solicit
prune
feedback. feedback.
Measurement units: Measurement units:
Microseconds. Microseconds.
3.4.2 Group Leave Delay. 3.4.2 Group Leave Delay.
Definition: Definition:
The time duration it takes a DUT/SUT to cease forwarding multicast The time duration it takes a DUT/SUT to cease forwarding multicast
packets after a corresponding IGMP "Leave Group" message has been packets after a corresponding IGMP "Leave Group" message has been
successfully offered to the DUT/SUT. successfully offered to the DUT/SUT.
Discussion: Discussion:
While it is important to understand how quickly a system can While it is important to understand how quickly a system can
process multicast frames; it may be beneficial to understand process multicast frames; it may be beneficial to understand
how quickly that same system can stop the process as well. how quickly that same system can stop the process as well.
Because of the number of variables that could impact this metric,
the metric may be a better characterization tool for a device or
system rather than a basis for comparisons with other devices.
Measurement units: Measurement units:
Microseconds. Microseconds.
Issues: Methodology may need to consider protocol-specific timeout Issues: Methodology may need to consider protocol-specific timeout
values. values.
3.5 Capacity 3.5 Capacity
This section offers terms relating to the identification of multicast This section offers terms relating to the identification of multicast
group limits of a DUT/SUT. group limits of a DUT/SUT.
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The maximum number of multicast groups a SUT/DUT can support The maximum number of multicast groups a SUT/DUT can support
while maintaining the ability to forward multicast frames while maintaining the ability to forward multicast frames
to all multicast groups registered to that SUT/DUT. to all multicast groups registered to that SUT/DUT.
Discussion: Discussion:
Measurement units: Measurement units:
Multicast groups. Multicast groups.
Issues: Issues:
The related methodology may have to consider the impact of multicast The related methodology may have to consider the impact of
multicast
sources per group on the ability of a SUT/DUT to "scale up" the sources per group on the ability of a SUT/DUT to "scale up" the
number of supportable multicast groups. number of supportable multicast groups.
3.6 Interaction 3.6 Interaction
Network forwarding devices are generally required to provide more Network forwarding devices are generally required to provide more
functionality than than the forwarding of traffic. Moreover, network functionality than than the forwarding of traffic. Moreover, network
forwarding devices may be asked to provide those functions in a variety of forwarding devices may be asked to provide those functions in a
environments. This section offers terms to assist in the charaterization variety of
of DUT/SUT behavior in consideration of potentially interacting factors. environments. This section offers terms to assist in the
charaterization
of DUT/SUT behavior in consideration of potentially interacting
factors.
3.6.1 Burdened Response. 3.6.1 Burdened Response.
Definition: Definition:
A measured response collected from a DUT/SUT in light of A measured response collected from a DUT/SUT in light of
interacting, or potentially interacting, distinct stimulii. interacting, or potentially interacting, distinct stimulii.
Discussion: Discussion:
Many metrics provide a one dimensional view into an operating Many metrics provide a one dimensional view into an operating
characteristic of a tested system. For example, the forwarding rate characteristic of a tested system. For example, the forwarding
rate
metric may yield information about the packet processing ability metric may yield information about the packet processing ability
of a device. Collecting that same metric in view of another of a device. Collecting that same metric in view of another
control variable can oftentimes be very insightful. Taking that same control variable can oftentimes be very insightful. Taking that
forwarding rate measurement, for instance, while the device's address same
forwarding rate measurement, for instance, while the device's
address
table is injected with an additional 50,000 entries may yield a table is injected with an additional 50,000 entries may yield a
different perspective. different perspective.
Measurement units: Measurement units:
While burdened response is not a specific metric, metrics of this A burdened response is a type of metric. Metrics of this
this type must follow guidelines when reporting results. this type must follow guidelines when reporting results.
The metric's principal result MUST be reported in conjunction with the The metric's principal result MUST be reported in conjunction with
the
contributing factors. contributing factors.
For example, in reporting a Forwarding Burdened Latency, the For example, in reporting a Forwarding Burdened Latency, the
latency measurement should be reported with respect to latency measurement should be reported with respect to
corresponding Offered Load and Forwarding Rates. corresponding Offered Load and Forwarding Rates.
Issues: Issues:
A Burdened response may be very illuminating when trying to A Burdened response may be very illuminating when trying to
characterize a single device or system. Extreme care must characterize a single device or system. Extreme care must
be exercised when attempting to use that characterization as be exercised when attempting to use that characterization as
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of such an interfering factor would be configuration mismatch of of such an interfering factor would be configuration mismatch of
a timer impacting a response process. a timer impacting a response process.
3.6.2 Forwarding Burdened Multicast Latency. 3.6.2 Forwarding Burdened Multicast Latency.
Definition: Definition:
A multicast latency taken from a DUT/SUT in the presence of A multicast latency taken from a DUT/SUT in the presence of
a traffic forwarding requirement. a traffic forwarding requirement.
Discussion: Discussion:
This burdened response metric builds on the Multicast Latency definition This burdened response metric builds on the Multicast Latency
definition
offered in section 3.3.1. It mandates that the DUT be subjected to offered in section 3.3.1. It mandates that the DUT be subjected to
an additional measure of traffic not required by the non-burdened an additional measure of traffic not required by the non-burdened
metric. metric.
It attempts to provide a means to evaluate how traffic load may or This metric attempts to provide a means by which to evaluate
may not impact a device's or system's packet processing delay. how traffic load may or may not impact a device's or system's
packet processing delay.
Measurement units: Measurement units:
Time units with enough precision to reflect the latencies measurements. Time units with enough precision to reflect the latencies
measurements.
Latency measurements MUST be reported with the corresponding sustained Latency measurements MUST be reported with the corresponding
sustained
Forwarding Rate and associated Offered Load. Forwarding Rate and associated Offered Load.
3.6.3 Forwarding Burdened Group Join Delay. 3.6.3 Forwarding Burdened Group Join Delay.
Definition: Definition:
A multicast Group Join Delay taken from a DUT/SUT in the presence of A multicast Group Join Delay taken from a DUT/SUT in the presence
of
a traffic forwarding requirement. a traffic forwarding requirement.
Discussion: Discussion:
This burdened response metric builds on the Group Join Delay definition This burdened response metric builds on the Group Join Delay
definition
offered in section 3.4.1. It mandates that the DUT be subjected to offered in section 3.4.1. It mandates that the DUT be subjected to
an additional measure of traffic not required by the non-burdened an additional measure of traffic not required by the non-burdened
metric. metric.
Many factors can contribute to different results, such as Many factors can contribute to different results, such as
the number or type of multicast-related protocols configured the number or type of multicast-related protocols configured
on the system under test. Other factors are physical topology and on the system under test. Other factors could be physical topology
"tree" configuration. or the logical multicast "tree" configuration.
Because of the number of variables that could impact this metric, Because of the number of variables that could impact this metric,
the metric may be a better characterization tool for a device or the metric may be a better characterization tool for a device or
system rather than a basis for comparisons with other devices. system rather than a basis for comparisons with other devices.
Measurement units: Measurement units:
Time units with enough precision to reflect the delay measurements. Time units with enough precision to reflect the delay measurements.
Delay measurements MUST be reported with the corresponding sustained Delay measurements MUST be reported with the corresponding
sustained
Forwarding Rate and associated Offered Load. Forwarding Rate and associated Offered Load.
4. Security Considerations 4. Security Considerations
Security issues are not addressed in this memo. This document addresses metrics and terminology relating to the
performance benchmarking of IP Multicast forwarding devices.
The information contained in this document does not impact the
security of the Internet.
5. References Methodologies regarding the collection of the metrics described
within this document may need to cite security considerations.
This document does not address methodological issues.
[1] Bradner, S. Benchmarking Terminology for Network 5. Acknowledgments
The IETF BMWG participants have made several comments and suggestions
regarding this work. Particular thanks goes to Scott Bradner, Brad
Cain, Eric Crawley, Bob Mandeville, David Newman, Shuching Sheih,
Dave Thaler, Chuck Winter, Zhaohui Zhang, and John Galgay for their
insightful review and assistance.
6. References
[Br91] Bradner, S. Benchmarking Terminology for Network
Interconnection Devices. RFC 1242. July, 1991. Interconnection Devices. RFC 1242. July, 1991.
[2] Bradner, S., McQuaid, J. Benchmarking Methodology for Network [Br96] Bradner, S., McQuaid, J. Benchmarking Methodology for Network
Interconnect Devices. RFC 1944. May, 1996. Interconnect Devices. RFC 1944. May, 1996.
[3] Craig, R. Terminology for Cell/Call Benchmarking. <draft-ietf- [Hu95] Huitema, C. "Routing in the Internet." Prentice-Hall, 1995.
bmwg-call-01.txt> March, 1997.
[4] Mandeville, R. Benchmarking Terminology for LAN Switching Devices. [Se98] Semeria, C. and Maufer, T. "Introduction to IP Multicast
Routing." http://www.3com.com/nsc/501303.html 3Com Corp., 1998.
[Ma98] Mandeville, R. Benchmarking Terminology for LAN Switching
Devices.
RFC 2285. February, 1998. RFC 2285. February, 1998.
5. Author's Address [Mt98] Maufer, T. "Deploying IP Multicast in the Enterprise."
Prentice-
Hall, 1998.
7. Author's Address
Kevin Dubray Kevin Dubray
Bay Networks, Inc. IronBridge Networks
600 Technology Park Drive 55 Hayden Avenue
M/S BL60-301 Lexington, MA 02421
Billerica, MA 01981 USA
(978) 916-3862
kdubray@baynetworks.com
or direct discussion to the Benchmarking Methodology Working Group: Phone: 781 402 8018
bmwg@harvard.edu EMail: kdubray@ironbridgenetworks.com
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