As per Relevance of the word terminology, we have this rfc below:
Network Working Group J.
Request for Comments: 3133 C.
Category: Informational ANC, Inc
June 2001
Terminology for Frame Relay
Status of this
This memo provides information for the Internet community. It
not specify an Internet standard of any kind. Distribution of
memo is unlimited
Copyright
Copyright (C) The Internet Society (2001). All Rights Reserved
This memo discusses and defines terms associated with
benchmarking tests and the results of these tests in the context
frame relay switching devices
I.
1.
This document provides terminology for Frame Relay switching devices
It extends terminology already defined for benchmarking
interconnect devices in RFCs 1242, 1944 and 2285. Although some
the definitions in this memo may be applicable to a broader group
network interconnect devices, the primary focus of the terminology
this memo is on Frame Relay Signaling
This memo contains two major sections: Background and Definitions
The background section provides the reader with an overview of
technology and IETF formalisms. The definitions section is
into two sub-sections. The formal definitions sub-section
provided as a courtesy to the reader. The measurement
sub-section contains performance metrics with inherent units
The BMWG produces two major classes of documents:
Terminology documents and Benchmarking Methodology documents.
Terminology documents present the benchmarks and other related terms
The Methodology documents define the procedures required to
the benchmarks cited in the corresponding Terminology documents
Dunn & Martin Informational [Page 1]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
For the purposes of computing several of the metrics, certain
conventions are required. Specifically
1) The notation sum {i=1 to N} A_i denotes: the summation of
instances of the observable A. For example, the set of
{1,2,3,4,5} would yield the result 15.
2) The notation max {I=1 to N} A_i and min {I=1 to N} A_i denotes
the maximum or minimum of the observable A over N instances.
example, given the set of observations {1,2,3,4,5}, max {i=1 to 5} =
5 and min {I=1 to 5} = 1.
The terms defined in this memo will be used in addition to
defined in RFCs 1242, 1944 and 2285. This memo is a product of
Benchmarking Methodology Working Group (BMWG) of the
Engineering Task Force(IETF).
2. Existing
RFC 1242, "Benchmarking Terminology for Network
Devices", should be consulted before attempting to make use of
document. RFC 1944, "Benchmarking Methodology for
Interconnect Devices", contains discussions of a number of
relevant to the benchmarking of switching devices and should also
consulted. RFC 2285, "Benchmarking Terminology for LAN
Devices", contains a number of terms pertaining to
distributions and datagram interarrival. For the sake of clarity
continuity this RFC adopts the template for definitions set out
Section 2 of RFC 1242.
II.
The definitions presented in this section have been divided into
groups. The first group is formal definitions, which are required
the definitions of the performance metrics but are not
strictly metrics. These definitions are subsumed from other
done in other working groups both inside and outside the IETF.
are provided as a courtesy to the reader
Dunn & Martin Informational [Page 2]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
1. Formal
1.1. Definition Format (from RFC1242)
Term to be defined
Definition: The specific definition for the term
Discussion: A brief discussion of the term, its application and
restrictions on measurement procedures
Specification: The working group and document in which the term
specified. Listed in the references
1.2. Frame Relay Related
1.2.1. Access
Definition: Access channel refers to the user access channel
which frame relay data travels. Within a given DS-3, T1 or E
physical line, a channel can be one of the following, depending
how the line is configured. Possible line configurations are
A. Unchannelized: The entire DS-3/T1/E1 line is considered a channel
where
The DS-3 line operates at speeds of 45 Mbps and is a single channel
The T1 line operates at speeds of 1.536 Mbps and is a single
consisting of 24 T1 time slots. The E1 line operates at speeds
1.984 Mbps and is a single channel consisting of 30 DS0 time slots
B. Channelized: The channel is any one of N time slots within a
line, where
The T1 line consists of any one or more channels. Each channel
any one of 24 time slots. The T1 line operates at speeds
multiples of 56/64 Kbps to 1.536 Mbps, with aggregate speed
exceeding 1.536 Mbps. The E1 line consists of one or more channels
Each channel is any one of 31 time slots. The E1 line operates
speeds in multiples of 64 Kbps to 1.984 Mbps, with aggregate
not exceeding 1.984 Mbps
C. Fractional: The T1/E1 channel is one of the following groupings
consecutively or non-consecutively assigned time slots
N DS0 time slots (NX56/64Kbps where N = 1 to 24 DS0 time slots
FT1 channel).
Dunn & Martin Informational [Page 3]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
N E1 time slots (NX64Kbps, where N = 1 to 30 DS0 time slots per E
channel).
Discussion: Access channels specify the physical layer
speed of a DTE or DCE. In the case of a DTE, this may not
to either the CIR or EIR. Specifically, based on the service
agreement in place, the user may not be able to access the
bandwidth of the access channel
Specification:
1.2.2. Access Rate (AR
Definition: The data rate of the user access channel. The speed
the access channel determines how rapidly (maximum rate) the end
can inject data into a frame relay network
Discussion: See Access Channel
Specification:
1.2.3. Backward Explicit Congestion Notification (BECN
Definition: BECN is a bit in the frame relay header. The bit is
by a congested network node in any frame that is traveling in
reverse direction of the congestion
Discussion: When a DTE receives frames with the BECN bit asserted,
should begin congestion avoidance procedures. Since the BECN
are traveling in the opposite direction as the congested traffic,
DTE will be the sender. The frame relay layer may communicate
possibility of congestion to higher layers, which have
congestion avoidance procedures, such as TCP. See Frame Relay Frame
Specification:
1.2.4. Burst Excess(Be
Definition: The maximum amount of uncommitted data (in bits)
excess of Committed Burst Size (Bc) that a frame relay network
attempt to deliver during a Committed Rate Measurement Interval (Tc).
This data (Be) generally is delivered with a lower probability
Bc. The network treats Be data as discard eligible
Discussion: See also Committed burst Size (Bc), Committed
Measurement Interval (Tc) and Discard Eligible (De).
Specification:
Dunn & Martin Informational [Page 4]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
1.2.5. Committed Burst Size (Bc
Definition: The maximum amount of data (in bits) that the
agrees to transfer, under normal conditions, during a time
Tc
Discussion: See also Excess Burst Size (Be) and Committed
Measurement Interval (Tc).
Specification:
1.2.6. Committed Information Rate (CIR
Definition: CIR is the transport speed the frame relay network
maintain between service locations when data is presented
Discussion: CIR specifies the guaranteed data rate between two
relay terminal connected by a frame relay network. Data presented
the network in excess of this data rate and below the
Information Rate (EIR) will be marked as Discard Eligible and may
dropped
Specification:
1.2.7. Committed Rate Measurement Interval (Tc
Definition: The time interval during which the user can send
Bc-committed amount of data and Be excess amount of data.
general, the duration of Tc is proportional to the "burstiness"
the traffic. Tc is computed (from the subscription parameters of
and Bc) as Tc = Bc/CIR. Tc is not a periodic time interval
Instead, it is used only to measure incoming data, during which
acts like a sliding window. Incoming data triggers the Tc interval
which continues until it completes its computed duration
Discussion: See also Committed Information Rate (CIR) and
Burst Size (Bc).
Specification:
1.2.8. Cyclic Redundancy Check (CRC
Definition: A computational means to ensure the accuracy of
transmitted between devices in a frame relay network.
mathematical function is computed, before the frame is transmitted
Dunn & Martin Informational [Page 5]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
at the originating device. Its numerical value is computed based
the content of the frame. This value is compared with a
value of the function at the destination device. See also
Check Sequence (FCS).
Discussion: CRC is not a measurement, but it is possible to
the amount of time to perform a CRC on a string of bits.
measurement will not be addressed in this document
Specification:
1.2.9. Data Communications Equipment (DCE
Definition: Term defined by both frame relay and X.25 committees
that applies to switching equipment and is distinguished from
devices that attach to the network (DTE).
Discussion: Also see DTE
Specification:
1.2.10. Data Link Connection Identifier (DLCI
Definition: A unique number assigned to a PVC end point in a
relay network. Identifies a particular PVC endpoint within a user'
access channel in a frame relay network and has local
only to that channel
Discussion: None
Specification:
1.2.11. Data Terminal Equipment (DTE
Definition: Any network equipment terminating a network
and is attached to the network. This is distinguished from
Communications Equipment (DCE), which provides switching
connectivity within the network
Discussion: See also DCE
Specification:
Dunn & Martin Informational [Page 6]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
1.2.12. Discard Eligible (DE
Definition: This is a bit in the frame relay header that provides
two level priority indicator, used to bias discard frames in
event of congestion toward lower priority frames. Similar to the
bit in ATM
Discussion: See Frame Relay Frame
Specification:
1.2.13. Discardable
Definition: Frames identified as being eligible to be dropped in
event of congestion
Discussion: The discard eligible field in the frame relay header
the correct -- and by far the most common -- means of
which frames may be dropped in the event of congestion. However,
is not the only means of identifying which frames may be dropped
There are at least three other cases that apply
In the first case, network devices may prioritize frame relay
by non-DE means. For example, many service providers
traffic on a per-PVC basis. In this instance, any traffic from
given DLCI (data link channel identifier) may be dropped
congestion, regardless of whether DE is set
In the second case, some implementations use upper-layer criteria
such as IP addresses or TCP or UDP port numbers, to
traffic within a single PVC. In this instance, the network
may evaluate discard eligibility based on upper-layer criteria
than the presence or absence of a DE bit
In the third case, the frame is discarded because of an error in
frame. Specifically, frames that are too long or too short,
that are not a multiple of 8 bits in length, frames with an
or unrecognized DLCI, frames with an abort sequence, frames
improper flag delimitation, and frames that fail FCS
Specification:
1.2.14. Discarded
Definition: Those frames dropped by a network device
Dunn & Martin Informational [Page 7]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
Discussion: Discardable and discarded frames are not synonymous
Some implementations may ignore DE bits or other criteria,
though they supposedly use such criteria to determine which frames
drop in the event of congestion
In other cases, a frame with its DE bit set may not be dropped.
example of this is in cases where congestion clears before the
can be evaluated
Specification:
1.2.15. Forward Explicit Congestion Notification (FECN
Definition: FECN is a bit in the frame relay header. The bit is
by a congested network node in any frame that is traveling in
same direction of the congestion
Discussion: When a DTE receives frames with the FECN bit asserted,
should begin congestion avoidance procedures. Since the FECN
are traveling in the same direction as the congested traffic, the
will be the receiver. The frame relay layer may communicate
possibility of congestion to higher layers, which have
congestion avoidance procedures, such as TCP. See Frame Relay Frame
Specification:
1.2.16. Frame Check Sequence (FCS
Definition: The standard 16-bit cyclic redundancy check used for
and frame relay frames. The FCS detects bit errors occurring in
bits of the frame between the opening flag and the FCS, and is
effective in detecting errors in frames no larger than 4096 octets
See also Cyclic Redundancy Check (CRC).
Discussion: FCS is not a measurement, but it is possible to
the amount of time to perform a FCS on a string of bits.
measurement will not be addressed in this document
Specification:
1.2.17. Frame Entry
Definition: Frame enters a network section or end system. The
occurs when the last bit of the closing flag of the frame crosses
boundary
Discussion: None
Dunn & Martin Informational [Page 8]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
Specification: FRF.13
1.2.18. Frame Exit
Definition: Frame exits a network section or end system. The
occurs when the first bit of the address field of the frame
the boundary
Discussion: None
Specification: FRF.13
1.2.19. Frame
Definition: A high-performance interface for packet-
networks; considered more efficient that X.25. Frame
technology can handle "bursty" communications that have
changing bandwidth requirements
Discussion: None
Specification:
1.2.20. Frame Relay
Definition: A logical grouping of information sent as a link-
unit over a transmission medium. Frame relay frames consist of
pair of flags, a header, a user data payload and a Frame
Sequence (FCS). Bit stuffing differentiates user data bytes
flags. By default, the header is two octets, of which 10 bits
the Data Link Connection Identifier (DLCI), 1 bit in each octet
used for address extension (AE), and 1 bit each for Forward
Congestion Notification (FECN), Backward Explicit
Notification (BECN) Command/Response (C/R) and Discard Eligible (DE).
The EA bit is set to one in the final octet containing the DLCI.
header may span 2, 3 or 4 octets
Dunn & Martin Informational [Page 9]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
Bit 7 6 5 4 3 2 1 0
|---|---|---|---|---|---|---|---|
| FLAG |
|-------------------------------|
| Upper 6 bits of DLCI |C/R|AE |
|-------------------------------|
| DLCI |FE |BE |DE |AE |
| |CN |CN | | |
|-------------------------------|
| User Data up to |
| 1600 Octets |
|-------------------------------|
| First Octet of FCS |
|-------------------------------|
| Second Octet of FCS |
|-------------------------------|
| FLAG |
|-------------------------------|
Discussion: Frame Relay headers spanning 3 or 4 octets will not
discussed in this document. Note, the measurements described
in this document are based on 2 octet headers. If longer headers
used, the metric values must take into account the
overhead. See BECN, DE, DLCI and FECN
Specification:
1.2.21. Excess Information Rate (EIR
Definition: See Burst Excess
Discussion: None
Specification:
1.2.22. Network Interworking (FRF.5)
Definition: FRF.5 defines a protocol mapping called
Interworking
Frame Relay and Asynchronous Transfer Mode (ATM). Protocol
occurs when the network performs conversions in such a way
within a common layer service, the protocol information of
protocol is extracted and mapped on protocol information of
protocol. This means that each communication terminal
different protocols. The common layer service provided in
Dunn & Martin Informational [Page 10]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
interworking scenario is defined by the functions, which are
to the two protocols. Specifically, the ATM terminal must
configured to interoperate with the Frame Relay network and
versa
Discussion: None
Specification: FRF.5
1.2.23. Port
Definition: See Access
Discussion: None
Specification:
1.2.24. Service Interworking (FRF.8)
Definition: FRF.8 defines a protocol encapsulation called
Interworking. Protocol encapsulation occurs when the conversions
the network or in the terminals are such that the protocols used
provide one service make use of the layer service provided by
protocol. This means that at the interworking point, the
protocols are stacked. When encapsulation is performed by
terminal, this scenario is also called interworking by port access
Specifically, the ATM service user performs no Frame
specific functions, and Frame Relaying service user performs no
service specific functions
Discussion: None
Specification: FRF.8
1.2.25. Service Availability
Definition: The service availability parameters report
operational readiness of individual frame relay virtual connections
Service availability is affected by service outages
Discussion: Service availability parameters provide metrics
assessment of frame relay network health and are used to
compliance with service level agreements. See Services Outages
Specification: FRF.13
Dunn & Martin Informational [Page 11]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
1.2.26. Service
Definition: Any event that interrupts the transport of frame
traffic. Two types of outages are differentiated
1) Fault outages: Outages resulting from faults in the network
thus tracked by the service availability parameters,
2) Excluded outages: Outages resulting from faults beyond the
of the network as well as scheduled maintenance
Discussion: Service availability can be defined on a per-VC
and/or on a per-port basis. Frame relay port-based
availability parameters are not addressed in this document.
Service Availability Parameters
Specification: FRF.13
2. Performance
2.1. Definition Format (from RFC1242)
Metric to be defined
Definition: The specific definition for the metric
Discussion: A brief discussion of the metric, its application
any restrictions on measurement procedures
Measurement units: Intrinsic units used to quantify this metric
This includes subsidiary units, e.g., microseconds are acceptable
the intrinsic unit is seconds
2.2.
2.2.1. Physical Layer-Plesiochronous Data Hierarchy (PDH
2.2.1.1. Alarm Indication Signal (AIS
Definition: An all 1's frame transmitted after the DTE or DCE
a defect for 2.5 s +/- 0.5 s
Discussion: An AIS will cause loss of information in the PDH frame
which contains a frame relay frame which may contain IP datagrams
Measurement units: Dimensionless
Dunn & Martin Informational [Page 12]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
2.2.1.2. Loss of Frame (LOF
Definition: An NE transmits an LOF when an OOF condition persists
Discussion: A LOF will cause loss of information in the PDH frame
which contains a frame relay frame which may contain IP datagrams
Measurement units: Dimensionless
2.2.1.3. Loss of Signal (LOS
Definition: Indicates that there are no transitions occurring in
received signal
Discussion: A LOS will cause loss of information in the PDH
which contains a frame relay frame which may contain IP datagrams
Measurement units: Dimensionless
2.2.1.4. Out of Frame (OOF
Definition: An NE transmits an OOF downstream when it
framing errors in a specified number of consecutive frame
positions
Discussion: An OOF will cause loss of information in the PDH
which contains a frame relay frame which may contain IP datagrams
Measurement units: Dimensionless
2.2.1.5. Remote Alarm Indication (RAI
Definition: Previously called Yellow Alarm. Transmitted upstream
an NE to indicate that it detected an LOS, LOF, or AIS
Discussion: An RAI will cause loss of information in the
PDH frame, which may contain a frame relay frame, which, in turn,
contain IP datagrams
Measurement units: Dimensionless
2.2.2. Frame Relay
2.2.2.1. Data Delivery Ratio (DDR
Definition: The DDR service level parameter reports the
effectiveness in transporting offered data (payload without
field or FCS) in one direction of a single virtual connection.
Dunn & Martin Informational [Page 13]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
DDR is a ratio of successful payload octets received to
payload octets transmitted. Attempted payload octets transmitted
referred to as DataOffered. Successfully delivered payload
are referred to as DataDelivered. These loads are
differentiated as being within the committed information rate or
burst excess
Three data relay ratios may be reported
Data Delivery Ratio (DDR):
(DataDelivered_c + DataDelivered_e DataDelivered_e+
DDR = --------------------------------- = -----------------
(DataOffered_c + DataOffered_e) DataOffered_e+
Data Delivery Ratio (DDR_c) for load consisting of frames within
committed information rate
DataDelivered_
DDR_c = -------------
DataOffered_
Data Delivery Ratio (DDR_e) for load in excess of the
information rate
DataDelivered_
DDR_e = ---------------
DataOffered_
DataDelivered_c: Successfully delivered data payload octets
committed information rate
DataDelivered_e: Successfully delivered data payload octets in
of CIR
DataDelivereD_e+c: Successfully delivered total data payload octets
including those within committed information rate and those in
of CIR
DataOffered_c: Attempted data payload octet transmissions
committed information rate
DataOffered_e: Attempted data payload octet transmissions in
of
Dunn & Martin Informational [Page 14]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
DataOffered_e+c: Attempted total data payload octet transmissions
including those within committed information rate and those in
of
Each direction of a full duplex connection has a discrete set of
delivery ratios
Discussion: Data delivery ratio measurements may not
representative of data delivery effectiveness for a
application. For example, the discarding of a small frame
an acknowledgement message may result in the retransmission of
large number of data frames. In such an event, a good data
ratio would be reported while the user experienced poor performance
Measurement units: dimensionless
2.2.2.2. Frame Delivery Ratio (FDR
Definition: The FDR service level parameter reports the
effectiveness in transporting an offered frame relay load in
direction of a single virtual connection. The FDR is a ratio
successful frame receptions to attempted frame transmissions
Attempted frame transmissions are referred to as Frames Offered
Successfully delivered frames are referred to as Frames Delivered
These loads may be further differentiated as being within
committed information rate or as burst excess
Frame Delivery Ratio (FDR):
Frame Delivery Ratio (FDR):
(FramesDelivered_c + FramesDelivered_e) FramesDelivered_e+
FDR = ------------------------------------- = -------------------
(FramesOffered_c + FramesOffered_e) FramesOffered_e+
Frame Delivery Ratio (FDR_c) for load consisting of frames within
committed information rate
FramesDelivered_
FDR_c = -----------------
FramesOffered_
Frame Delivery Ratio (FDR_c) for load in excess of the
information rate
FramesDelivered_
FDR_e = -----------------
FramesOffered_
Dunn & Martin Informational [Page 15]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
FramesDelivered_c: Successfully delivered frames within
information rate
FramesDelivered_e: Successfully delivered frames in excess of CIR
FramesDelivered_e+c: Successfully delivered total frames,
those within committed information rate and those in excess of CIR
FramesOffered_c: Attempted frame transmissions within
information rate
FramesOffered_e: Attempted frame transmissions in excess of
FramesOffered_e+c: Attempted total frame transmissions,
those within committed information rate and those in excess of CIR
An independent set of frame delivery ratios exists for each
of a full duplex connection
Discussion: Frame delivery ratio measurements may not
representative of frame delivery effectiveness for a
application. For example, the discarding of a small frame
an acknowledgement message may result in the retransmission of
large number of data frames. In such an event, a good data
ratio would be reported while the
Measurement units: dimensionless
2.2.2.3. Frame Discard Ratio (FDR
Definition: The number of received frames that are discarded
of a frame error divided by the total number of transmitted frames
one direction of a single virtual connection. Frame errors
defined as follows
1) frames that are too long or too short
2) frames that are not a multiple of 8 bits in length
3) frames with an invalid or unrecognized DLCI
4) frames with an abort sequence
5) frames with improper flag delimitation
6) frames that fail FCS
Dunn & Martin Informational [Page 16]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
The formal definition of frame discard ratio is as follows
sum {i=1 to N} fr_
FDR = -------------------
sum {i=1 to N} ft_i
fr_i is the number of successfully delivered frames for a
DLCI at second
ft_i is the total number of attempted frame transmissions within
committed plus extended information rate for a particular DLCI
second i
Discussion: Frame discards can adversely effect applications
on IP over FR. In general, frame discards will negatively impact
throughput; however, in the case of frame discard due to frame error
frame discard will improve performance by dropping errored frames
As a result, these frames will not adversely effect the forwarding
retransmitted
Measurement units: dimensionless
2.2.2.4. Frame Error Ratio (FER
Definition: The number of received frames that contain an error
the frame payload divided by the total number of transmitted
in one direction of a single virtual connection
The formal definition of frame error ratio is as follows
sum {i=1 to N} fe_
FER = -------------------
sum {i=1 to N} ft_i
fe_i is the number of frames containing a payload error for
particular DLCI at second
ft_i is the total number of attempted frame transmissions within
committed plus the extended information rate for a particular DLCI
second i. This statistic includes those frames which have an
Dunn & Martin Informational [Page 17]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
in the Frame Check Sequence (FCS). Frame errors in the absence
FCS errors can be detected by sending frames containing a
pattern; however, this indicates an equipment defect
Discussion: The delivery of frames containing errors will
effect applications running on IP over FR. Typically, these
are caused by transmission errors and flagged as failed FCS frames
however, when Frame Relay to ATM Network interworking is used,
error may be injected in the frame payload which, in turn,
encapsulated into an AAL5 PDU (see RFC 2761 for a discussion of AAL
related metrics).
Measurement units: dimensionless
2.2.2.5. Frame Excess Ratio (FXR
Definition: The number of frames received by the network and
as excess traffic divided by the total number of transmitted
in one direction of a single virtual connection. Frames which
sent to the network with DE set to zero are treated as excess
more than Bc bits are submitted to the network during the
Information Rate Measurement Interval (Tc). Excess traffic may
may not be discarded at the ingress if more than Bc + Be bits
submitted to the network during Tc. Traffic discarded at the
is not recorded in this measurement. Frames which are sent to
network with DE set to one are also treated as excess traffic
The formal definition of frame excess ratio is as follows
sum {i=1 to N} fc_
FXR = 1 - -------------------
sum {i=1 to N} ft_i
fc_i is the total number of frames which were submitted within
traffic contract for a particular DLCI at second
ft_i is the total number of attempted frame transmissions for
particular DLCI at second i
Discussion: Frame discards can adversely effect applications
on IP over FR. Specifically, frame discards will negatively
TCP throughput
Measurement units: dimensionless
Dunn & Martin Informational [Page 18]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
2.2.2.6. Frame Loss Ratio (FLR
Definition: The FLR is a ratio of successful frame receptions
attempted frame transmissions at the committed information rate,
one direction of a single virtual connection. Attempted
transmissions are referred to as Frames Offered.
delivered frames are referred to as Frames Delivered
The formal definition of frame loss ratio is as follows
FramesDelivered_
FLR = 1- -----------------
FramesOffered_c
FramesDelivered_c is the successfully delivered frames
committed information rate for a given
FramesOffered_c is the attempted frame transmissions within
information rate for a given
An independent set of frame delivery ratios exists for each
of a full duplex connection
Discussion: Frame delivery loss measurements may not
representative of frame delivery effectiveness for a
application. For example, the loss of a small frame containing
acknowledgement message may result in the retransmission of a
number of data frames. In such an event, a good data delivery
would be reported while the
Measurement units: dimensionless
2.2.2.7. Frame Policing Ratio (FPR
Definition: The number of frames received by the network and
as excess traffic and dropped divided by the total number of
frames, in one direction of a single virtual connection.
which are sent to the network with DE set to zero are treated
excess when more than Bc bits are submitted to the network during
Committed Information Rate Measurement Interval (Tc). Excess
may or may not be discarded at the ingress if more than Bc + Be
are submitted to the network during Tc. Traffic discarded at
ingress is recorded in this measurement. Frames which are sent
the network with DE set to one are also treated as excess traffic
Dunn & Martin Informational [Page 19]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
The formal definition of frame excess ratio is as follows
sum {i=1 to N} fr_
FPR = 1- -------------------
sum {i=1 to N} ft_i
fr_i is the successfully delivered frames for a particular DLCI
second
ft_i is the total number of attempted frame transmissions for
particular
at second i
Discussion: Frame discards can adversely effect applications
on IP over FR. Specifically, frame discards will negatively
TCP throughput
2.2.2.8. Frame Transfer Delay (FTD
Definition: The time required to transport frame relay data
measurement point 1 to measurement point 2. The frame transfer
is the difference in seconds between the time a frame
measurement point 1 and the time the same frame enters
point 2, in one direction of a single virtual connection. The
definition of frame transfer delay is as follows
FTD = 1/N * sum {i=1 to N} t2_i - t1_i
t1_i is the time in seconds when the ith frame leaves
point 1 (i.e., frame exit event),
t2 is the time in seconds when the ith frame arrives at
point 2 (i.e., frame entry event
N is the number of frames received during a measurement interval T
FTD is computed for a specific DLCI and a specified
period of T seconds. The computation does not include frames
are transmitted during the measurement period but not received
Dunn & Martin Informational [Page 20]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
Discussion: While frame transfer delay is usually computed as
average and, thus, can effect neither IP nor TCP performance
applications such as voice over IP may be adversely effected
excessive FTD
Measurement units: seconds
2.2.2.9. Frame Transfer Delay Variation (FTDV
Definition: The variation in the time required to transport
relay data from measurement point 1 to measurement point 2.
frame transfer delay variation is the difference in seconds
maximum frame transfer delay and the minimum frame transfer delay,
one direction of a single virtual connection. The formal
of frame transfer delay is as follows
FTDV = max {i=1 to N} FTD_i - min {i=1 to N} FTD_i
FTD and N are defined as above
Discussion: Large values of FTDV can adversely effect TCP round
time calculation and, thus, TCP throughput
Measurement units: seconds
3. Security
As this document is solely for providing terminology and
neither a protocol nor an implementation, there are no
considerations associated with this document
4.
Internet Engineering Task
The IETF takes no position regarding the validity or scope of
intellectual property or other rights that might be claimed
pertain to the implementation or use of the technology
in this document or the extent to which any license under
rights might or might not be available; neither does it
that it has made any effort to identify any such rights
Information on the IETFs procedures with respect to rights
standards-track and standards-related documentation can be
in BCP-11. Copies of claims of rights made available
publication and any assurances of licenses to be made available
or the result of an attempt made to obtain a general license
Dunn & Martin Informational [Page 21]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
permission for the use of such proprietary rights by
or users of this specification can be obtained from the
Secretariat
The IETF invites any interested party to bring to its
any copyrights, patents or patent applications, or
proprietary rights, which may cover technology that may
required to practice this standard. Please address
information to the IETF Executive Director
Frame Relay
Copyright Frame Relay Forum 1998. All Rights Reserved
References FRF, FRF.5, FRF.8 and FRF.13 and translations of
may be copied and furnished to others, and works that comment
or otherwise explain it or assist in their implementation may
prepared, copied, published and distributed, in whole or in part
without restriction of any kind, provided that the above
notice and this paragraph are included on all such copies
derivative works. However, these documents themselves may not
modified in any way, such as by removing the copyright notice
references to the Frame Relay Forum, except as needed for
purpose of developing Frame Relay standards (in which case
procedures for copyrights defined by the Frame Relay Forum must
followed), or as required to translate it into languages
than English
Dunn & Martin Informational [Page 22]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
5.
[DN] Private communication from David Newman, Network Test, Inc
[FRF] Frame Relay Forum Glossary, http://www.frforum.com, 1999.
[FRF.5] Frame Relay Forum, Frame Relay/ATM PVC Network
Implementation Agreement, December 1994.
[FRF.8] Frame Relay Forum, Frame Relay/ATM PVC Service
Implementation Agreement, April 1995.
[FRF.13] Frame Relay Forum, Service Level Definitions
Agreement, August 1998.
[FRMIB] Rehbehn, K and D. Fowler, "Definitions of Managed
for Frame Relay Service", RFC 2954, October 2000.
6. Editors'
Jeffrey
Advanced Network Consultants, Inc
4214 Crest
Ellicott City, MD 21043
Phone: +1 (410) 750-1700
EMail: Jeffrey.Dunn@worldnet.att.
Cynthia
Advanced Network Consultants, Inc
4214 Crest
Ellicott City, MD 21043
Phone: +1 (410) 750-1700
EMail: Cynthia.E.Martin@worldnet.att.
Dunn & Martin Informational [Page 23]
RFC 3133 Terminology for Frame Relay Benchmarking June 2001
Full Copyright
Copyright (C) The Internet Society (2001). All Rights Reserved
This document and translations of it may be copied and furnished
others, and derivative works that comment on or otherwise explain
or assist in its implementation may be prepared, copied,
and distributed, in whole or in part, without restriction of
kind, provided that the above copyright notice and this paragraph
included on all such copies and derivative works. However,
document itself may not be modified in any way, such as by
the copyright notice or references to the Internet Society or
Internet organizations, except as needed for the purpose
developing Internet standards in which case the procedures
copyrights defined in the Internet Standards process must
followed, or as required to translate it into languages other
English
The limited permissions granted above are perpetual and will not
revoked by the Internet Society or its successors or assigns
This document and the information contained herein is provided on
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED,
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
Funding for the RFC Editor function is currently provided by
Internet Society
Dunn & Martin Informational [Page 24]
if you see any problems within the linking, don't worry be happy,
this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.
RFC documents can be found at I.E.T.F.
Relevance System Copyright © 2002 Spectrum WorldResearch
other technical nosh by ServerMasters Corporation
collaboration of BobX
