Core10/100 Conformance Test Report

Fast Ethernet Consortium
MAC Test Suite version 4.3
InterOperability Lab — 121 Technology Drive, Suite 2 — Durham, NH 03824 — (603) 862-0239
July 26, 2004
Mr. Hugh Cao
Actel Corporation, Building 1
2061 Stierlin Court
Mountain View, CA 94043-4655
Mr. Cao:
Enclosed are the results for MAC conformance testing performed on the Actel Platform 8051 Core10/100 MAC
testing board with Actel ProASIC APA600 MAC, and VS31AL PHY. The tests are based on Clause 4 of IEEE
Standard 802.3, 2002 edition. The tests performed are a subset of the MAC Conformance Test Suite available at the
InterOperability Lab’s web site:
ftp://ftp.iol.unh.edu/pub/ethernet/test_suites/mac/mac.pdf
As always, we welcome any comments regarding this Test Suite.
During the testing process, the following issues were uncovered:
Test
Result
4.6.2 – Truncated
The DUT was not observed to properly implement the standard defined collision backoff
Binary Exponential
algorithm.
BackOff test
If you have any questions about the test procedures or results, please contact me via e-mail at mnd3@iol.unh.edu or
by phone at (603) 862-0239.
Sincerely
Marc Deschenes
Ethernet MAC Test Suite
Actel Platform 8051 Co re10/100 MAC testing board
The following table contains possible results and their meanings:
Result
Interpretation
PASS
FAIL
PASS with
Comments
Warning
The DUT was observed to exhibit conformant behavior.
The DUT was observed to exhibit non-compliant behavior.
The DUT was observed to exhibit conformant behavior, however this behavior deviated from
previous compliant results. An additional explanation of the situation is included.
The DUT was observed to exhibit behavior that is not recommended.
Refer to
Comments
From the observations, a valid pass or fail could not be determined. An additional
explanation of the situation is included.
Not Appl icable
Not Available
Not Tested
Borderline
Informative
Ethernet Data Link Layer
The DUT does not support the technology required to perform these tests.
Due to testing station or time limitations, the tests could not be performed, or were performed
in a limited capacity.
Not tested due to time constraint of the test period.
The observed values of the specified parameter are valid at one extreme, and invalid at the
other extreme.
Results are for informative purposes only and are not judged on a pass or fail basis.
2
MAC Test Suite
Ethernet MAC Test Suite
Actel Platform 8051 Co re10/100 MAC testing board
Group 1:
Test #
4.1.1
Test Label
Reception of Frames with FCS Errors
a
b
Result
PASS
PASS
Comments on Test Procedure
Purpose: To verify that the device under test detects frames with FCS errors and reports a frameCheckError.
a.
b.
The DUT shall detect and discard the frame with an invalid value in the FCS field, and, if clause 30 is implemented, log a
FCS error.
The reception of test frames with an invalid FCS field should not affect the reception of valid request frames preceding or
following the Test Frame by a minimum InterFrameGap.
Comments on Test Results
a.
b.
The DUT was observed to properly discard a frame with an invalid CRC. The statistics of the DUT were unavailable during
testing.
The reception of test frames with invalid FCS fields was not observed to affect the reception of the valid request frames.
Test #
Test Label
4.1.2
Reception of Fragments and Runts
a
b
c
Result
PASS
PASS
PASS
Comments on Test Procedure
Purpose: To verify that the device under test discards collision fragments.
a.
b.
c.
The DUT should discard all fragments and runts less than 64 bytes in length.
The DUT should properly discard each of the sequences listed below:
1. 7 octets of preamble
2. 7 octets of preamble and SFD
3. 7 octets of preamble, SFD and the MAC address of the DUT
4. 7 octets of preamble, SFD, the MAC address of the DUT and an arbitrary source address
The reception of fragments or runts should not interfere with the reception of valid MAC frames.
Comments on Test Results
a.
b.
All fragments and runts were discarded by the DUT. The statistics of the DUT were unavailable during testing.
The DUT was observed to behave in the following ways when receiving each of the different test fragments:
1. The DUT discarded the fragment consisting of: 7 octets of preamble.
2. The DUT discarded the fragment consisting of: 7 octets of preamble and SFD.
3. The DUT discarded the fragment consisting of: 7 octets of preamble, SFD and the MAC address of the DUT.
4. The DUT discarded the fragment consisting of: 7 octets of preamble, SFD, the MAC address of the DUT and an arbitrary
source address.
c. The reception of fragments or runts did not interfere with the reception of valid MAC frames.
Ethernet Data Link Layer
3
MAC Test Suite
Ethernet MAC Test Suite
Actel Platform 8051 Co re10/100 MAC testing board
Test #
4.1.3
Test Label
Reception of Frames Greater than the Maximum Permitted Frame Size
a
b
c
d
Result
PASS
Not Applicable
PASS
PASS
Comments on Test Procedure
Purpose: To verify that the device under test (DUT) discards frames greater than maxFrameSize.
a.
b.
c.
d.
DUT should discard or truncate though not transmit, untagged frames greater than 1518 bytes in length
DUT should discard or truncate though not transmit, tagged frames greater than 1522 bytes in length
The DUT should discard or truncate and respond to the test frames containing two CRC values. The DUT shall not transmit,
untagged frames greater than 1518 bytes in length. If the DUT accepted these test frames and discarded the test frames of the
same size in part A, then the DUT must truncate and respond to the test frames of the same size with a valid CRC value in
bytes 1515 – 1518 and an invalid CRC in the last 4 bytes of the frame. (Otherwise this would indicate that the DUT
improperly checked the CRC value twice, once before truncation and once after.) The DUT may optionally log the test
frames as frameTooLong errors.
All valid frames preceding and following the test frames should be replied to.
Comments on Test Results
a.
b.
c.
d.
The DUT was observed toreply to untagged frames up to 1518 bytes in length. The DUT was observed to discard untagged
frames greater than 1518 bytes in length.
The DUT was not observed to support VLAN tagging.
The DUT was observed to discard the untagged frames that contained a valid 1518 byte frame.
The reception of the test frames did not interfere with the reception of valid MAC frames.
Test #
Test Label
4.1.4
Frames with Length Errors
a
b
Result
Not Applicable
Not Applicable
Comments on Test Procedure
Purpose: To verify that the device under test (DUT) discards frames with invalid length values.
a.
b.
The DUT should discard all frames with invalid length values.
All valid frames preceding and following the test frames should be replied to.
Comments on Test Results
Note: The properly encapsulated 64-byte 802.3 SNAP frame was not replied to by the DUT. The remaining frame length tests
could not be performed because the DUT did not respond to the 802.3 SNAP frame.
Ethernet Data Link Layer
4
MAC Test Suite
Ethernet MAC Test Suite
Actel Platform 8051 Co re10/100 MAC testing board
Test #
Test Label
4.1.5
Receive Frames with Excess Pad
a
b
Result
Not Applicable
Not Applicable
Comments on Test Procedure
Purpose: To verify that the device under test (DUT) accepts frames with excessive padding.
a.
b.
The DUT should accept each test frame and reply with a frame that does not contain padding.
The reception of test frames should not affect the reception of the valid request frames.
Comments on Test Results
Note: The properly encapsulated 64-byte 802.3 SNAP frame was not replied to by the DUT. The remaining frame length tests
could not be performed because the DUT did not respond to the 802.3 SNAP frame.
Test #
Test Label
a
4.1.6
Jabber Frame Reception and Recovery
b
Result
PASS
PASS REFER
TO
COMMENTS
Comments on Test Procedure
Purpose: To verify that the device under test (DUT) is able to withstand and recover from the reception of worst-case jabber
transmissions.
a.
b.
The DUT should discard jabber frames.
All valid frames preceding and following the test frames should be replied to.
Comments on Test Results
b.
When receciving a jabber frame followed by a valid frame separated by a minimum inter frame gap the DUT was observed to
delay the response to the valid frame until another frame was received by the DUT. When this occurred the DUT was
observed to send a reply to both the frame that was being delayed as well as the new frame.
Ethernet Data Link Layer
5
MAC Test Suite
Ethernet MAC Test Suite
Actel Platform 8051 Co re10/100 MAC testing board
Test #
Test Label
4.1.7
Start of Frame Delimiter Error Reception and Recovery
a
b
c
Result
PASS
PASS
PASS
Comments on Test Procedure
Purpose: To verify that the device under test (DUT) discards frames which do not contain a valid Start of Frame Delimiter (SFD).
a.
b.
c.
The DUT should discard a test frame where the SFD is replaced by another byte of preamble (bit pattern 10101010) in an
otherwise valid frame.
The DUT should discard a test frame where the bit pattern 10011011 replaces the SFD in an otherwise valid frame.
All valid frames preceding and following the test frames should be replied to.
Comments on Test Results
a.
b.
c.
The DUT was observed to discard the test frame.
The DUT was observed to discard the frame with 7 bytes of preamble and 10011011 in place of an SFD.
The reception of the test frames did not interfere with the reception of valid MAC frames.
Test #
4.1.8
Test Label
Frames with Alignment Errors
a
b
c
Result
PASS
PASS
PASS
Comments on Test Procedure
Purpose: To verify that the device under test (DUT) detects and discards frames with alignment errors.
a.
b.
c.
The DUT should truncate the test frame to the nearest octet and accept it.
The DUT should truncate the test frame to the nearest octet, discard it and report an alignmentError.
The reception of valid frames preceding and following the test frames separated by the minimum inter-frame gap should not
be affected.
Comments on Test Results
a. The DUT was observed to accept the test frame.
b. The DUT was observed to discard the test frame. The statistics of the DUT were unavailable during testing.
c. The reception of the test frames did not interfere with the reception of valid MAC frames.
Ethernet Data Link Layer
6
MAC Test Suite
Ethernet MAC Test Suite
Actel Platform 8051 Co re10/100 MAC testing board
Test #
4.1.9
Test Label
Preamble Error Reception and Recovery
a
b
c
d
Result
PASS
PASS
PASS
PASS
Comments on Test Procedure
Purpose: To verify that the device under test (DUT) accepts frames which contain errors with preamble.
a.
b.
c.
d.
The DUT should accept a frame, which has preamble replaced with:
10101010 00000000 00000000 00000000 00000000 00000000 00000000 10101011
The DUT should accept a frame, which has preamble replaced with:
10101010 01111111 11111111 11111111 11111111 11111111 11111111 10101011
The DUT should accept a frame, which has preamble replaced with:
10101010 10101010 10101010 10101010 10101010 10101000 10101111 10101011
All valid frames preceding and following the test frames should be replied to.
Comments on Test Results
a.
b.
c.
d.
The DUT was observed to accept the frame with preamble replaced with above-mentioned sequence.
The DUT was observed to accept the frame with preamble replaced with above-mentioned sequence.
The DUT was observed to accept the frame with preamble replaced with above-mentioned sequence.
The reception of the test frames did not interfere with the reception of valid MAC frames.
Ethernet Data Link Layer
7
MAC Test Suite
Ethernet MAC Test Suite
Actel Platform 8051 Co re10/100 MAC testing board
Group 2:
Test #
Test Label
4.2.1
Transmit proper SFD and preamble
Result
REFER TO
COMMENTS
Comments on Test Procedure
Purpose: To verify that the device under test (DUT) properly encapsulates a frame with preamble and SFD, and that the
combination of the two is 8 bytes.
The DUT should always encapsulate frames with a combined 8 bytes of preamble and SFD.
Comments on Test Results
Note: No preamble or SFD problems were observed while testing the DUT. However this test is designed to test the DUT's
transmit abilities under stressful traffic loads. When testing End Stations they will typically not transmit rapidly enough for us to
determine a Pass/Fail indication.
Test #
Test Label
4.2.2
Transmission of Minimum interFrameGa p
Result
REFER TO
COMMENTS
Comments on Test Procedure
Purpose: To verify that the device under test (DUT) enforces the minimum interFrameGap (IFG) of 96 bit times.
The DUT should not transmit frames separated by less than minimum IFG, even under the most stressful situations.
Comments on Test Results
Note: No inter-frame gap problems were observed while testing the DUT. However this test is designed to test the DUT's
transmit abilities under stressful traffic loads. When testing End Stations they will typically not transmit rapidly enough for us to
determine a Pass/Fail indication.
Test #
Test Label
4.2.3
Transmit proper length within the Length/Type Field
Comments on Test Procedure
Result
Not Applicable
Purpose: To verify that the device under test (DUT) properly calculates the length of the data in the Data/Pad field.
The DUT should transmit 802.3 Ethernet frames with a length value equal to the amount of data in the Data/Pad field. If the
frame is greater than minFrameSize that frame should not contain pad.
Comments on Test Results
Note: The properly encapsulated 64-byte 802.3 SNAP frame was not replied to by the DUT. The remaining frame length tests
could not be performed because the DUT did not respond to the 802.3 SNAP frame.
Ethernet Data Link Layer
8
MAC Test Suite
Ethernet MAC Test Suite
Actel Platform 8051 Co re10/100 MAC testing board
Test #
4.2.4
Comments on Test Procedure
Test Label
Compute and transmit proper CRC
Result
PASS
Purpose: To verify that the device under test (DUT) correctly calculates the CRC-32 value for the frame being transmitted and
assigns it to the FCS field.
The CRC-32 value transmitted by the DUT should match the value calculated by the testing station.
Comments on Test Results
The CRC calculated by the DUT was verified to be correct by the testing platform.
Test #
4.2.5
Comments on Test Procedure
Test Label
Receive variable preamble
Result
PASS
Purpose: To verify that the device under test (DUT) accepts frames with varied amounts of preamble.
The DUT should accept frames that contain at least 1 byte of preamble followed by an SFD.
Comments on Test Results
The DUT was observed to accept frames with 1 to 64 bytes of preamble and an SFD.
Test #
4.2.6
Test Label
Receive all Frame Sizes
a
b
Result
PASS
PASS
Comments on Test Procedure
Purpose: To verify that the device under test (DUT) accepts all valid sized frames.
a.
b.
The DUT should accept all valid untagged frames from minFrameSize (64 bytes) to maxUntaggedFrameSize (1518 bytes).
If VLAN tagging is supported, the DUT should accept all tagged frames from minFrameSize (64 bytes) to
maxUntaggedFrameSize (1518 bytes). The DUT may optionally accept tagged frames 1519 bytes to maxUntaggedFrameSize
+ qTagPrefixSize (1522 bytes).
Comments on Test Results
a.
b.
The DUT was observed to accept all of the different untagged frame sizes.
The DUT was observed to accept all of the different tagged frame sizes from 64 bytes to 1522 bytes in length.
Ethernet Data Link Layer
9
MAC Test Suite
Ethernet MAC Test Suite
Actel Platform 8051 Co re10/100 MAC testing board
Test #
4.2.7
Comments on Test Procedure
Test Label
Reception of minimum interFrameGap
Result
PASS
Purpose: To verify that device under test (DUT) is capable of receiving frames separated by a minimum interFrameGap
The DUT should accept two frames separated by minimum IFG (96 bit times).
Comments on Test Results
The DUT was observed to accept both frames that were separated by a minimum IFG.
Ethernet Data Link Layer
10
MAC Test Suite
Ethernet MAC Test Suite
Actel Platform 8051 Co re10/100 MAC testing board
Group 3:
Test #
4.3.1
Comments on Test Procedure
Test Label
Does not Defer
Result
PASS
Purpose: To verify that the device under test (DUT) does not defer to carrier sense while in full duplex mode.
The DUT should not defer the transmission of a frame in waiting to a long carrier event while in full duplex mode.
Comments on Test Results
The DUT was not observed to defer while in full duplex mode.
Test #
4.3.2
Comments on Test Procedure
Test Label
No Collisions
Result
PASS
Purpose: To verify that no collisions occur when the device under test (DUT) is in full duplex mode.
The DUT should not detect and enforce a collision when frames are being transmitted and received simultaneously in full duplex
mode.
Comments on Test Results
No collisions or collision fragments were observed while in full duplex mode.
Ethernet Data Link Layer
11
MAC Test Suite
Ethernet MAC Test Suite
Actel Platform 8051 Co re10/100 MAC testing board
Group 4:
Test #
4.4.1
Test Label
Collisions During Preamble and SFD within slotTime
a
b
Result
PASS
PASS
Comments on Test Procedure
Purpose: To verify that the device under test (DUT) properly detects and enforces collisions that occur during the transmission of
preamble and SFD while within slotTime.
a.
b.
The DUT should detect the collision, complete the transmission of preamble and SFD, and transmit a 32-bit jam pattern.
The DUT should attempt to retransmit the frame involved in the collision.
Comments on Test Results
a.
b.
The DUT was observed to detect the collision, complete the transmission of the preamble and SFD and transmit a 32-bit jam
pattern.
The DUT was observed to retransmit the frame.
Test #
4.4.2
Test Label
Collisions in Data within slotTime
a
b
Result
PASS
PASS
Comments on Test Procedure
Purpose: To verify that the device under test (DUT) properly detects and enforces collisions that occur during the transmission of
data while with slotTime.
a.
b.
The DUT should detect the collision, cease transmission of data and transmit a 32-bit jam pattern.
The DUT should attempt to retransmit the frame involved in the collision.
Comments on Test Results
a.
b.
The DUT was observed to detect the collision, cease transmission of data and transmit a 32-bit jam pattern.
The DUT was observed to retransmit the frame.
Ethernet Data Link Layer
12
MAC Test Suite
Ethernet MAC Test Suite
Actel Platform 8051 Co re10/100 MAC testing board
Test #
Test Label
4.4.3
Collisions in Data Outside of slotTime while Not Bursting
A
B
Result
PASS
Informative
Comments on Test Procedure
Purpose: To verify that the device under test (DUT) properly detects and enforces collisions that occur during the transmission of
data outside of slotTime while not in burst mode.
a.
b.
The DUT should detect the late collision, cease transmission of data and transmit a 32-bit jam pattern.
The DUT may or may not attempt to retransmit a frame involved in a late collision.
Comments on Test Results
a.
b.
The DUT was observed to detect the collision, cease transmission of data and transmit a 32-bit jam pattern.
The DUT was not observed to retransmit the frame.
Ethernet Data Link Layer
13
MAC Test Suite
Ethernet MAC Test Suite
Actel Platform 8051 Co re10/100 MAC testing board
Group 5:
Test #
4.5.1
Comments on Test Procedure
Test Label
Defer to Carrier Sense while Frame Waiting
Result
PASS
Purpose: To verify that the device under test (DUT) defers to carrier sense when it has a frame waiting to be transmitted.
While in half duplex, the DUT should delay the transmission of a frame in waiting until the completion of a long carrier event
Comments on Test Results
The DUT was observed to properly defer to carrier events.
Test #
4.5.2
Comments on Test Procedure
Test Label
Deference after Collision
Result
PASS
Purpose: To verify that the device under tes t (DUT) continues to observe the deference process when it is attempting to retransmit
after a collision.
After a collision has occurred, in half duplex, the DUT should delay any retransmission attempts until carrier sense is no longer
asserted.
Comments on Test Results
The DUT was observed to properly defer to carrier events.
Test #
4.5.3
Comments on Test Procedure
Test Label
InterFrame Spacing
Result
PASS
Purpose: To verify that the device under test (DUT) observes the 2/3 rule for interFrameSpacing.
While in half duplex, the DUT should cause a collision to occur if carrier sense is assert during interFrameSpacingPart2, which
should be at least the last third of IFS but may be as large as IFS (96 bit times). By observing when the DUT starts causing
collisions it is possible to determine the size of interFrameSpacing parts 1 and 2. The interFrameSpacingPart1 of the DUT should
not be greater than 2/3 of IFS (64 bit times).
Comments on Test Results
The value of interFrameSpacingPart1 was observed to be 56 ± 4 bit times.
Ethernet Data Link Layer
14
MAC Test Suite
Ethernet MAC Test Suite
Actel Platform 8051 Co re10/100 MAC testing board
Group 6:
Test #
4.6.1
Comments on Test Procedure
Test Label
Retransmission Attempt Limit
Result
PASS
Purpose: To verify that the device under test (DUT) allows a maximum of 15 attempts for retransmission after a collision.
After a collision has occurred the DUT should attempt to retransmit the frame involved in the collision. Should multiple
collisions occur during the attempted transmission of a frame, the DUT should continue to attempt to retransmit the frame until
the number of attempts equals attemptLimit (16). The DUT should, therefore, not attempt to transmit a frame more than 16 times
(initial attempt + 15 retransmission attempts). The collision fragments should be properly formed.
Comments on Test Results
Upon multiple collisions with a frame being transmitted from the DUT, the testing station captured a total of 16 collision
fragments. The collision fragments were properly formed.
Test #
Test Label
4.6.2
Truncated Binary Exponential BackOff Test
a
b
Result
PASS
FAIL
Comments on Test Procedure
Purpose: To verify that the device under test (DUT) correctly calculates the time to wait before attempting retransmission of a
frame.
a.
b.
The combined average backOff time for each backOff attempt should not be more aggressive than the expected average for
that attempt.
The variable ‘r’ should be a uniformly distributed random number in the range of [0, 2k – 1] where k=min(n,10).
Comments on Test Results
a.
b.
The average backoff for the retransmission attempts was not observed to be significantly more aggressive than the allowable
range to over a 99% Confidence level.
According to the histogram data we can say with over a 99% Confidence level that the backoff times chosen were not
uniformly distributed over the standard specified backoff ranges, specifically retry attempt 12. For further information please
refer to the enclosed histograms. If you would like a copy of the gathered data please let us know.
Ethernet Data Link Layer
15
MAC Test Suite
Histogram of the Backoff of the First Retransmission Attempt
18000
16000
14000
Occurrences
12000
10000
8000
6000
4000
2000
0
0
1
Backoff in Slot Times
Histogram of the Backoff of the Second Retransmission Attempt
9000
8000
7000
Occurrences
6000
5000
4000
3000
2000
1000
0
0
1
2
Backoff in Slot Times
3
Histogram of the Backoff of the Third Retransmission Attempt
4500
4000
3500
Occurrences
3000
2500
2000
1500
1000
500
0
0
1
2
3
4
Backoff in Slot Times
5
6
7
Histogram of the Backoff of the Fourth Retransmission Attempt
2500
Occurrences
2000
1500
1000
500
0
0
1
2
3
4
5
6
7
8
Backoff in Slot Times
9
10
11
12
13
14
15
Histogram of the Backoff of the Fifth Retransmission Attempt
1200
1000
Occurrences
800
600
400
200
0
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Backoff in Slot Times
Histogram of the Backoff of the Sixth Retransmission Attempt
600
500
300
200
100
Backoff in Slot Times
62
60
58
56
54
52
50
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
0
Occurrences
400
Histogram of the Backoff of the Seventh Retransmission Attempt
350
300
200
150
100
50
Backoff in Slot Times
124
120
116
112
108
104
100
96
92
88
84
80
76
72
68
64
60
56
52
48
44
40
36
32
28
24
20
16
12
8
4
0
0
Occurrences
250
Histogram of the Backoff of the Eighth Retransmission Attempt
180
160
140
100
80
60
40
20
Backoff in Slot Times
248
240
232
224
216
208
200
192
184
176
168
160
152
144
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
16
8
0
0
Occurrences
120
Backoff in Slot Times
510
495
480
465
450
435
420
405
390
375
360
345
330
315
300
285
270
255
240
225
210
195
180
165
150
135
120
105
90
75
60
45
30
15
0
Number of Occurrences
Histogram of the Backoff of the Ninth Retransmission Attempt
120
100
80
60
40
20
0
Backoff in Slot Times
1015
986
957
928
899
870
841
812
783
754
725
696
667
638
609
580
551
522
493
464
435
406
377
348
319
290
261
232
203
174
145
116
87
58
29
0
Number of Occurrences
Histogram of the Backoff of the 10th Retransmission Attempt
70
60
50
40
30
20
10
0
Backoff in Slot Times
1015
986
957
928
899
870
841
812
783
754
725
696
667
638
609
580
551
522
493
464
435
406
377
348
319
290
261
232
203
174
145
116
87
58
29
0
Number of Occurrences
Histogram of the Backoff of the 11th Retransmission Attempt
70
60
50
40
30
20
10
0
Backoff in Slot Times
1015
986
957
928
899
870
841
812
783
754
725
696
667
638
609
580
551
522
493
464
435
406
377
348
319
290
261
232
203
174
145
116
87
58
29
0
Number of Occurrences
Histogram of the Backoff of the 12th Retransmission Attempt
60
50
40
30
20
10
0
Backoff in Slot Times
1015
986
957
928
899
870
841
812
783
754
725
696
667
638
609
580
551
522
493
464
435
406
377
348
319
290
261
232
203
174
145
116
87
58
29
0
Number of Occurrences
Histogram of the Backoff of the 13th Retransmission Attempt
90
80
70
60
50
40
30
20
10
0
Backoff in Slot Times
1015
986
957
928
899
870
841
812
783
754
725
696
667
638
609
580
551
522
493
464
435
406
377
348
319
290
261
232
203
174
145
116
87
58
29
0
Number of Occurrences
Histogram of the Backoff of the 14th Retransmission Attempt
80
70
60
50
40
30
20
10
0
Backoff in Slot Times
1015
986
957
928
899
870
841
812
783
754
725
696
667
638
609
580
551
522
493
464
435
406
377
348
319
290
261
232
203
174
145
116
87
58
29
0
Number of Occurrences
Histogram of the Backoff of the 15th Retransmission Attempt
60
50
40
30
20
10
0
Histogram of the Backoff of the Combined 10th-15th Retransmission Attempts
400
350
300
200
150
100
50
Backoff in Slot Times
1015
986
957
928
899
870
841
812
783
754
725
696
667
638
609
580
551
522
493
464
435
406
377
348
319
290
261
232
203
174
145
116
87
58
29
0
0
Occurrences
250