draft-ietf-bmwg-fr-term-04.txt   draft-ietf-bmwg-fr-term-05.txt 
Network Working Group J. H. Dunn Network Working Group J. H. Dunn
INTERNET-DRAFT C. E. Martin INTERNET-DRAFT C. E. Martin
Expires: February, 2001 ANC, Inc. Expires: February, 2001 ANC, Inc.
July, 2000 October, 2000
Terminology for Frame Relay Benchmarking Terminology for Frame Relay Benchmarking
<draft-ietf-bmwg-fr-term-04.txt> <draft-ietf-bmwg-fr-term-05.txt>
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with all This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026. Internet-Drafts are working provisions of Section 10 of RFC2026. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas, and documents of the Internet Engineering Task Force (IETF), its areas, and
its working groups. Note that other groups may also distribute working its working groups. Note that other groups may also distribute working
documents as Internet-Drafts. documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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Specification: FRF Specification: FRF
1.2.7. Committed Rate Measurement Interval (Tc) 1.2.7. Committed Rate Measurement Interval (Tc)
Definition: The time interval during which the user can send only Bc- Definition: The time interval during which the user can send only Bc-
committed amount of data and Be excess amount of data. In general, the committed amount of data and Be excess amount of data. In general, the
duration of Tc is proportional to the "burstiness" of the traffic. Tc is duration of Tc is proportional to the "burstiness" of the traffic. Tc is
computed (from the subscription parameters of CIR and Bc) as Tc = Bc/CIR. computed (from the subscription parameters of CIR and Bc) as Tc = Bc/CIR.
Tc is not a periodic time interval. Instead, it is used only to measure Tc is not a periodic time interval. Instead, it is used only to measure
incoming data, during which it acts like a sliding window. Incoming data incoming data, during which it acts like a sliding window. Incoming data
triggers the Tc interval, which continues until it completes its commuted triggers the Tc interval, which continues until it completes its computed
duration. duration.
Discussion: See also Committed Information Rate (CIR) and committed Burst Discussion: See also Committed Information Rate (CIR) and committed Burst
Size (Bc). Size (Bc).
Specification: FRF Specification: FRF
1.2.8. Cyclic Redundancy Check (CRC) 1.2.8. Cyclic Redundancy Check (CRC)
Definition: A computational means to ensure the accuracy of frames Definition: A computational means to ensure the accuracy of frames
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2.2. Definitions 2.2. Definitions
2.2.1. Physical Layer- Plesiochronous Data Hierarchy (PDH) 2.2.1. Physical Layer- Plesiochronous Data Hierarchy (PDH)
2.2.1.1. Alarm Indication Signal (AIS) 2.2.1.1. Alarm Indication Signal (AIS)
Definition: An all 1's frame transmitted after the DTE or DCE detects a Definition: An all 1's frame transmitted after the DTE or DCE detects a
defect for 2.5 s +/- 0.5 s. defect for 2.5 s +/- 0.5 s.
Discussion: An AIS will cause loss of information in the PDH frame which Discussion: An AIS will cause loss of information in the PDH frame, which
contains a frame relay frame which may contain IP datagrams. contains a frame relay frame which may contain IP datagrams.
Measurement units: Seconds. Measurement units: Dimensionless.
2.2.1.2. Loss of Frame (LOF) 2.2.1.2. Loss of Frame (LOF)
Definition: An NE transmits an LOF when an OOF condition persists. Definition: An NE transmits an LOF when an OOF condition persists.
Discussion: A LOF will cause loss of information in the PDH frame which Discussion: A LOF will cause loss of information in the PDH frame, which
contains a frame relay frame which may contain IP datagrams. contains a frame relay frame which may contain IP datagrams.
Measurement units: Seconds. Measurement units: Dimensionless.
2.2.1.3. Loss of Signal (LOS) 2.2.1.3. Loss of Signal (LOS)
Definition: Indicates that there are no transitions occurring in the Definition: Indicates that there are no transitions occurring in the
received signal. received signal.
Discussion: A LOS will cause loss of information in the PDH frame which Discussion: A LOS will cause loss of information in the PDH frame which
contains a frame relay frame which may contain IP datagrams. contains a frame relay frame which may contain IP datagrams.
Measurement units: Seconds. Measurement units: Dimensionless.
2.2.1.4. Out of Frame (OOF) 2.2.1.4. Out of Frame (OOF)
Definition: An NE transmits an OOF downstream when it receives framing Definition: An NE transmits an OOF downstream when it receives framing
errors in a specified number of consecutive frame bit positions. errors in a specified number of consecutive frame bit positions.
Discussion: An OOF will cause loss of information in the PDH frame which Discussion: An OOF will cause loss of information in the PDH frame which
contains a frame relay frame which may contain IP datagrams. contains a frame relay frame which may contain IP datagrams.
Measurement units: Seconds. Measurement units: Dimensionless.
2.2.1.5. Remote Alarm Indication (RAI) 2.2.1.5. Remote Alarm Indication (RAI)
Definition: Previously called Yellow Alarm. Transmitted upstream by an NE Definition: Previously called Yellow Alarm. Transmitted upstream by an NE
to indicate that it detected an LOS, LOF, or AIS. to indicate that it detected an LOS, LOF, or AIS.
Discussion: An RAI will cause loss of information in the transmitted PDH Discussion: An RAI will cause loss of information in the transmitted PDH
frame, which may contain a frame relay frame, which, in turn, may contain frame, which may contain a frame relay frame, which, in turn, may contain
IP datagrams. IP datagrams.
Measurement units: Seconds. Measurement units: Dimensionless.
2.2.2. Frame Relay Layer 2.2.2. Frame Relay Layer
2.2.2.1. Data Delivery Ratio (DDR) 2.2.2.1. Data Delivery Ratio (DDR)
Definition: The DDR service level parameter reports the networks Definition: The DDR service level parameter reports the networks
effectiveness in transporting offered data (payload without address field effectiveness in transporting offered data (payload without address field
or FCS) in one direction of a single virtual connection. The DDR is a ratio or FCS) in one direction of a single virtual connection. The DDR is a ratio
of successful payload octets received to attempted payload octets of successful payload octets received to attempted payload octets
transmitted. Attempted payload octets transmitted are referred to as transmitted. Attempted payload octets transmitted are referred to as
DataOffered. Successfully delivered payload octets are referred to as DataOffered. Successfully delivered payload octets are referred to as
DataDelivered. These loads are further differentiated as being within the DataDelivered. These loads are further differentiated as being within the
committed information rate or as burst excess. committed information rate or as burst excess.
Three data relay ratios may be reported: Three data relay ratios may be reported:
Data Delivery Ratio (DDR): Data Delivery Ratio (DDR):
(DataDelivered_c + DataDelivered_e DataDelivered_e+c (DataDelivered_c + DataDelivered_e DataDelivered_e+c
DDR = ------------------------------- = --------------- DDR = --------------------------------- = -----------------
(DataOffered_c + DataOffered_e) DataOffered_e+c (DataOffered_c + DataOffered_e) DataOffered_e+c
Data Delivery Ratio (DDR_c) for load consisting of frames within the Data Delivery Ratio (DDR_c) for load consisting of frames within the committed
committed information rate: information rate:
DataDelivered_c DataDelivered_c
DDR_c = ------------- DDR_c = -------------
DataOffered_c DataOffered_c
Data Delivery Ratio (DDR_e) for load in excess of the committed information Data Delivery Ratio (DDR_e) for load in excess of the committed information
rate: rate:
DataDelivered_e DataDelivered_e
DDR_e = ------------- DDR_e = ---------------
DataOffered_e DataOffered_e
where where
DataDelivered_c: Successfully delivered data payload octets within
committed information rate
DataDelivered_e: Successfully delivered data payload octets in excess of DataDelivered_c: Successfully delivered data payload octets within committed
CIR information rate,
DataDelivereD_e+c: Successfully delivered total data payload octets, DataDelivered_e: Successfully delivered data payload octets in excess of CIR,
including those within committed information rate and those in excess of
CIR
DataOffered_c: Attempted data payload octet transmissions within DataDelivereD_e+c: Successfully delivered total data payload octets, including those within committed information rate and those in excess of CIR,
committed information rate
DataOffered_e: Attempted data payload octet transmissions in excess of DataOffered_c: Attempted data payload octet transmissions within committed
CIR information rate,
DataOffered_e+c: Attempted total data payload octet transmissions, DataOffered_e: Attempted data payload octet transmissions in excess of CIR
including those within committed information rate and those in excess of
CIR
Each direction of a full duplex connection has a discrete set of data and
delivery ratios.
Discussion: Data delivery ratio measurements may not be representative of DataOffered_e+c: Attempted total data payload octet transmissions, including
data delivery effectiveness for a given application. For example, the those within committed information rate and those in excess of CIR
discarding of a small frame containing an acknowledgement message may
result in the retransmission of a large number of data frames. In such an Each direction of a full duplex connection has a discrete set of data delivery
event, a good data delivery ratio would be reported while the user ratios.
experienced poor performance.
Discussion: Data delivery ratio measurements may not be representative of data
delivery effectiveness for a given application. For example, the discarding of
a small frame containing an acknowledgement message may result in the
retransmission of a large number of data frames. In such an event, a good data
delivery ratio would be reported while the user experienced poor performance.
Measurement units: dimensionless. Measurement units: dimensionless.
2.2.2.2. Frame Delivery Ratio (FDR) 2.2.2.2. Frame Delivery Ratio (FDR)
Definition: The FDR service level parameter reports the networks Definition: The FDR service level parameter reports the networks effectiveness
in transporting an offered frame relay load in one direction of a single virtual
connection. The FDR is a ratio of 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 the committed information rate or
effectiveness in transporting an offered frame relay load in one direction as burst excess.
of a single virtual connection. The FDR is a ratio of 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 the committed information rate or as burst excess.
Frame Delivery Ratio (FDR): Frame Delivery Ratio (FDR):
(FramesDelivered_c + FramesDelivered_e) FramesDelivered_e+c (FramesDelivered_c + FramesDelivered_e) FramesDelivered_e+c
FDR = ----------------------------------- = ------------------ FDR = ------------------------------------- = -------------------
(FramesOffered_c + FramesOffered_e) FramesOffered_e+c (FramesOffered_c + FramesOffered_e) FramesOffered_e+c
Frame Delivery Ratio (FDR_c) for load consisting of frames within the Frame Delivery Ratio (FDR_c) for load consisting of frames within the committed
committed information rate: information rate:
FramesDelivered_c FramesDelivered_c
FDR_c = ---------------- FDR_c = -----------------
FramesOffered_c FramesOffered_c
Frame Delivery Ratio (FDR_c) for load in excess of the committed Frame Delivery Ratio (FDR_c) for load in excess of the committed information
information rate: rate:
FramesDelivered_e FramesDelivered_e
FDR_e = ---------------- FDR_e = -----------------
FramesOffered_e FramesOffered_e
where where
FramesDelivered_c: Successfully delivered frames within committed
information rate
FramesDelivered_e: Successfully delivered frames in excess of CIR FramesDelivered_c: Successfully delivered frames within committed information rate,
FramesDelivered_e+c: Successfully delivered total frames, including FramesDelivered_e: Successfully delivered frames in excess of CIR,
those within committed information rate and those in excess of CIR
FramesOffered_c: Attempted frame transmissions within committed FramesDelivered_e+c: Successfully delivered total frames, including those within committed information rate and those in excess of CIR,
information rate
FramesOffered_c: Attempted frame transmissions within committed information rate,
FramesOffered_e: Attempted frame transmissions in excess of CIR FramesOffered_e: Attempted frame transmissions in excess of CIR
FramesOffered_e+c: Attempted total frame transmissions, including those
within committed information rate and those in excess of CIR
An independent set of frame delivery ratios exists for each direction of a and
full duplex connection.
Discussion: Frame delivery ratio measurements may not be representative of FramesOffered_e+c: Attempted total frame transmissions, including those within committed information rate and those in excess of CIR.
frame delivery effectiveness for a given application. For example, the
discarding of a small frame containing an acknowledgement message may An independent set of frame delivery ratios exists for each direction of a full
result in the retransmission of a large number of data frames. In such an duplex connection.
event, a good data delivery ratio would be reported while the user
Discussion: Frame delivery ratio measurements may not be representative of frame
delivery effectiveness for a given application. For example, the discarding of
a small frame containing an acknowledgement message may result in the
retransmission of a large number of data frames. In such an event, a good data
delivery ratio would be reported while the user
Measurement units: dimensionless. Measurement units: dimensionless.
2.2.2.3. Frame Discard Ratio (FDR) 2.2.2.3. Frame Discard Ratio (FDR)
Definition: The number of received frames that are discarded because of a Definition: The number of received frames that are discarded because of a frame
frame error divided by the total number of received frames in one direction error divided by the total number of transmitted frames in one direction of a
of a single virtual connection. Frame errors are defined as follows: single virtual connection. Frame errors are defined as follows:
1) frames that are too long or too short, 1) frames that are too long or too short,
2) frames that are not a multiple of 8 bits in length, 2) frames that are not a multiple of 8 bits in length,
3) frames with an invalid or unrecognized DLCI, 3) frames with an invalid or unrecognized DLCI,
4) frames with an abort sequence, 4) frames with an abort sequence,
5) frames with improper flag delimitation, 5) frames with improper flag delimitation,
6) frames that fail FCS. 6) frames that fail FCS.
The formal definition of frame discard ratio is as follows: The formal definition of frame discard ratio is as follows:
FDR = sum {i=1 to N} fr_i sum {i=1 to N} fr_i
------------------- FDR = -------------------
sum {i=1 to N} ft_i, sum {i=1 to N} ft_i,
where where
fr_i is the number of successfully delivered frames for a particular DLCI at
second i, fr_i is the number of successfully delivered frames for a particular DLCI at second i
and and
ft_i is the total number of attempted frame transmissions within the committed ft_i is the total number of attempted frame transmissions within the committed plus extended information rate for a particular DLCI at second i.
information rate for a particular DLCI at second i.
Discussion: Frame discards can adversely effect applications running on IP over Discussion: Frame discards can adversely effect applications running on IP over
FR. In general, frame discards will negatively impact TCP throughput; however, FR. In general, frame discards will negatively impact TCP throughput; however,
in the case of frame discard due to frame error, frame discard will improve 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 performance by dropping errored frames. As a result, these frames will not
adversely effect the forwarding of retransmitted frames. adversely effect the forwarding of retransmitted frames
Measurement units: dimensionless. Measurement units: dimensionless.
2.2.2.4. Frame Error Ratio (FER) 2.2.2.4. Frame Error Ratio (FER)
Definition: The number of received frames that contain an error in the frame Definition: The number of received frames that contain an error in the frame
payload divided by the total number of received frames in one direction of a payload divided by the total number of transmitted frames in one direction of a
single virtual connection. single virtual connection.
The formal definition of frame error ratio is as follows: The formal definition of frame error ratio is as follows:
FDR = sum {i=1 to N} fe_i sum {i=1 to N} fe_i
------------------- FER = -------------------
sum {i=1 to N} ft_i, sum {i=1 to N} ft_i,
where where
fe_i is the number of frames containing a payload error for a particular DLCI at
second i, fe_i is the number of frames containing a payload error for a particular DLCI at second i
and and
ft_i is the total number of attempted frame transmissions within the committed ft_i is the total number of attempted frame transmissions within the committed plus the extended information rate for a particular DLCI at second i. This statistic includes those frames which have an error in the Frame Check Sequence (FCS). Frame errors in the absence of FCS errors can be detected by sending frames containing a known pattern; however, this indicates an equipment defect.
information rate for a particular DLCI at second i.
Discussion: The delivery of frames containing errors will adversely effect Discussion: The delivery of frames containing errors will adversely effect
applications running on IP over FR. Typically, these errors are caused by applications running on IP over FR. Typically, these errors are caused by
transmission errors and flagged as failed FCS frames; however, when Frame Relay transmission errors and flagged as failed FCS frames; however, when Frame Relay
to ATM Network interworking is used, an error may be injected in the frame to ATM Network interworking is used, an error may be injected in the frame
payload which, in turn, is encapsulated into an AAL5 PDU (see RFC 2761 for a payload which, in turn, is encapsulated into an AAL5 PDU (see RFC 2761 for a
discussion of AAL5 related metrics). discussion of AAL5 related metrics).
Measurement units: dimensionless. Measurement units: dimensionless.
2.2.2.5. Frame Excess Ratio (FXR) 2.2.2.5. Frame Excess Ratio (FXR)
Definition: The number of frames received by the network and treated as excess Definition: The number of frames received by the network and treated as excess
traffic divided by the total number of received frames in one direction of a traffic divided by the total number of transmitted frames in one direction of a
single virtual connection. Frames which are sent to the network with DE set to single virtual connection. Frames which are sent to the network with DE set to
zero are treated as excess when more than Bc bits are submitted to the network zero are treated as excess when more than Bc bits are submitted to the network
during the Committed Information Rate Measurement Interval (Tc). Excess traffic during the Committed Information Rate Measurement Interval (Tc). Excess traffic
may or may not be discarded at the ingress if more than Bc + Be bits are may or may not be discarded at the ingress if more than Bc + Be bits are
submitted to the network during Tc. Traffic discarded at the ingress is not submitted to the network during Tc. Traffic discarded at the ingress is not
recorded in this measurement. Frames which are sent to the network with DE set recorded in this measurement. Frames which are sent to the network with DE set
to one are also treated as excess traffic. to one are also treated as excess traffic.
The formal definition of frame excess ratio is as follows: The formal definition of frame excess ratio is as follows:
FXR = sum {i=1 to N} fc_i sum {i=1 to N} fc_i
1 - ------------------- FXR = 1 - -------------------
sum {i=1 to N} ft_i, sum {i=1 to N} ft_i,
where where
fc_i is the total number of frames which were submitted within the traffic fc_i is the total number of frames which were submitted within the traffic
contract for a particular DLCI at second i contract for a particular DLCI at second i
and and
ft_i is the total number of attempted frame transmissions for a particular DLCI ft_i is the total number of attempted frame transmissions for a particular DLCI at second i.
at second i.
Discussion: Frame discards can adversely effect applications running on IP over Discussion: Frame discards can adversely effect applications running on IP over
FR. Specifically, frame discards will negatively impact TCP throughput. FR. Specifically, frame discards will negatively impact TCP throughput.
Measurement units: dimensionless. Measurement units: dimensionless.
2.2.2.6. Frame Loss Ratio (FLR) 2.2.2.6. Frame Loss Ratio (FLR)
Definition: The FLR is a ratio of successful frame receptions to attempted frame Definition: The FLR is a ratio of successful frame receptions to attempted frame
transmissions at the committed information rate, in one direction of a single transmissions at the committed information rate, in one direction of a single
virtual connection. Attempted frame transmissions are referred to as Frames virtual connection. Attempted frame transmissions are referred to as Frames
Offered. Successfully delivered frames are referred to as Frames Delivered. Offered. Successfully delivered frames are referred to as Frames Delivered.
The formal definition of frame loss ratio is as follows: The formal definition of frame loss ratio is as follows:
FramesDelivered_c FramesDelivered_c
FLR = 1- ----------------- FLR = 1- -----------------
FramesOffered_c FramesOffered_c,
where where
FramesDelivered_c is the successfully delivered frames within committed FramesDelivered_c is the successfully delivered frames within committed
information rate for a given DLCI, information rate for a given DLCI
and and
FramesOffered_c is the attempted frame transmissions within committed FramesOffered_c is the attempted frame transmissions within committed
information rate for a given DLCI information rate for a given DLCI
An independent set of frame delivery ratios exists for each direction of a full An independent set of frame delivery ratios exists for each direction of a full
duplex connection. duplex connection.
Discussion: Frame delivery loss measurements may not be representative of frame Discussion: Frame delivery loss measurements may not be representative of frame
delivery effectiveness for a given application. For example, the loss of a delivery effectiveness for a given application. For example, the loss of a
small frame containing an acknowledgement message may result in the small frame containing an acknowledgement message may result in the
retransmission of a large number of data frames. In such an event, a good data retransmission of a large number of data frames. In such an event, a good data
delivery ratio would be reported while the user delivery ratio would be reported while the user
Measurement units: dimensionless. Measurement units: dimensionless.
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direction of a single virtual connection. Frames which are sent to the network direction of a single virtual connection. Frames which are sent to the network
with DE set to zero are treated as excess when more than Bc bits are submitted with DE set to zero are treated as excess when more than Bc bits are submitted
to the network during the Committed Information Rate Measurement Interval (Tc). to the network during the Committed Information Rate Measurement Interval (Tc).
Excess traffic may or may not be discarded at the ingress if more than Bc + Be Excess traffic may or may not be discarded at the ingress if more than Bc + Be
bits are submitted to the network during Tc. Traffic discarded at the ingress bits are submitted to the network during Tc. Traffic discarded at the ingress
is recorded in this measurement. Frames which are sent to the network with DE is recorded in this measurement. Frames which are sent to the network with DE
set to one are also treated as excess traffic. set to one are also treated as excess traffic.
The formal definition of frame excess ratio is as follows: The formal definition of frame excess ratio is as follows:
FPR = sum {i=1 to N} fr_i sum {i=1 to N} fr_i
1- ------------------- FPR = 1- -------------------
sum {i=1 to N} ft_i, sum {i=1 to N} ft_i,
where where
fr_i is the successfully delivered frames for a particular DLCI at second i,
fr_i is the successfully delivered frames for a particular DLCI at second i
and and
ft_i is the total number of attempted frame transmissions for a particular DLCI ft_i is the total number of attempted frame transmissions for a particular DLCI
at second i. at second i.
Discussion: Frame discards can adversely effect applications running on IP over Discussion: Frame discards can adversely effect applications running on IP over
FR. Specifically, frame discards will negatively impact TCP throughput. FR. Specifically, frame discards will negatively impact TCP throughput.
2.2.2.8. Frame Transfer Delay (FTD) 2.2.2.8. Frame Transfer Delay (FTD)
Definition: The time required to transport frame relay data from measurement Definition: The time required to transport frame relay data from measurement
point 1 to measurement point 2. The frame transfer delay is the difference in point 1 to measurement point 2. The frame transfer delay is the difference in
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Definition: The time required to transport frame relay data from measurement Definition: The time required to transport frame relay data from measurement
point 1 to measurement point 2. The frame transfer delay is the difference in point 1 to measurement point 2. The frame transfer delay is the difference in
seconds between the time a frame exits measurement point 1 and the time the same seconds between the time a frame exits measurement point 1 and the time the same
frame enters measurement point 2, in one direction of a single virtual frame enters measurement point 2, in one direction of a single virtual
connection. The formal definition of frame transfer delay is as follows: connection. The formal definition of frame transfer delay is as follows:
FTD = 1/N * sum {i=1 to N} t2_i - t1_i, FTD = 1/N * sum {i=1 to N} t2_i - t1_i,
where where
t1 is the time in seconds when a frame left measurement point 1 (i.e., frame
exit event),
t2 is the time in seconds when a frame arrived at measurement point 2 (i.e., t1_i is the time in seconds when the ith frame leaves measurement point 1 (i.e., frame exit event),
frame entry event). FTD is computed for a specific DLCI and a specified
integration period of N seconds t2 is the time in seconds when the ith frame arrives at measurement point 2 (i.e., frame entry event)
and
N is the number of frames received during a measurement interval T.
FTD is computed for a specific DLCI and a specified integration period of T seconds. The computation does not include frames which are transmitted during the measurement period but not received.
Discussion: While frame transfer delay is usually computed as an average Discussion: While frame transfer delay is usually computed as an average
and, thus, can effect neither IP nor TCP performance, applications such as and, thus, can effect neither IP nor TCP performance, applications such as
voice over IP may be adversely effected by excessive FTD. voice over IP may be adversely effected by excessive FTD.
Measurement units: seconds. Measurement units: seconds.
2.2.2.9. Frame Transfer Delay Variation (FTDV) 2.2.2.9. Frame Transfer Delay Variation (FTDV)
Definition: The variation in the time required to transport frame relay data Definition: The variation in the time required to transport frame relay data
from measurement point 1 to measurement point 2. The frame transfer delay from measurement point 1 to measurement point 2. The frame transfer delay
variation is the difference in seconds between maximum frame transfer delay and variation is the difference in seconds between maximum frame transfer delay and
the minimum frame transfer delay, in one direction of a single virtual the minimum frame transfer delay, in one direction of a single virtual
connection. The formal definition of frame transfer delay is as follows connection. The formal definition of frame transfer delay is as follows:
FTDV = max {i=1 to N} FTD_i - min {i=1 to N} FTD_i. FTDV = max {i=1 to N} FTD_i - min {i=1 to N} FTD_i.
where where
FTD is defined as above.
FTD and N are defined as above.
Discussion: Large values of FTDV can adversely effect TCP round trip time Discussion: Large values of FTDV can adversely effect TCP round trip time
calculation and, thus, TCP throughput. calculation and, thus, TCP throughput.
Measurement units: seconds. Measurement units: seconds.
3. Security Considerations. 3. Security Considerations.
As this document is solely for providing terminology and describes As this document is solely for providing terminology and describes
neither a protocol nor an implementation, there are no security neither a protocol nor an implementation, there are no security
considerations associated with this document. considerations associated with this document.
 End of changes. 

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