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would not exceed the requirements of the receiving hardware and collisions would not pose a problem. Usually this detailed information is not easy to obtain and difficult for users to calculate. The standard requires generation of sufficient preamble bits to make sure a frame can be received when operated within specification limits (i.e. applying the 5-4-3 rule).
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According to the original
Ethernet protocol, a signal sent out over the collision domain must reach every part of the network within a specified length of time. The 5-4-3 rule ensures this. Each segment and repeater that a signal goes through adds a small amount of time to the process, so the rule is
162:
This rule divides a collision domain into two types of physical segments: mixing segments, and link segments. User segments can have users' systems connected to them. Link segments (FOIRL, 10BASE-T, 10BASE-FL, or 10BASE-FB) are used to connect the network's repeaters together. The rule mandates that
191:
Various repeaters (hubs) may use slightly different implementations and operate differently. Each repeater would lose more or less bits while locking on, some could lose as many as 5 or 6 bits. You could create a network with more repeaters if you made sure the total number of lost preamble bits
187:
and then locks onto the bitstream. Once locked on, it would then repeat each bit out the other port(s). However, a number of bits would be consumed at the start while the repeater was locking onto the bit stream. As the frame propagated through each repeater the preamble would get shorter and
64:
there should be at most 5 segments tied together with 4 repeaters, with up to 3 mixing segments (10BASE5, 10BASE2, or 10BASE-FP). Link segments can be 10BASE-T, 10BASE-FL or 10BASE-FB. This rule is also designated the
195:
In a lab at DEC they knew how many bits their repeaters would lose and knowing this were able to create an 11 segment, 10 repeater, 3 active segment (11-10-3) network that maintained a round trip delay of less than
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to network equipment or the connections between different pieces of network equipment. These connections generally use dedicated media for transmitting and receiving, simplifying collision detection.
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because each port on a switch constitutes a separate collision domain. With mixed repeated and switched networks, the rule's scope ends at a switched port.
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In addition to the necessity of reliable collision detection, a frame cannot be repeated too many times. A repeater normally listens for the
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shorter. Too many bits lost meant that an end node may not have enough preamble bits to lock on and the entire frame would be missed.
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of the five segments may be mixing segments. This last requirement applies only to 10BASE5, 10BASE2, and 10BASE-FP Ethernet segments.
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802.3-2008 Part 3: Carrier sense multiple access with
Collision Detection (CSMA/CD) Access Method and Physical Layer Specifications
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segment: The medium connection, including connectors, between Medium
Dependent Interfaces (MDIs) in a CSMA/CD local area network.
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Ethernet varieties, a segment would therefore correspond to a single coax cable and any devices tapped into it â a
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84:, allows 2 repeaters on the single network and does not allow any hosts on the connection between repeaters.
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were the only types of
Ethernet networks available. The rules only apply to shared-medium
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and a sufficient number of preamble bits that all end nodes functioned properly.
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13. System considerations for multisegment 10 Mb/s baseband networks
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155:, a network segment corresponds to the individual connection between
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13. System considerations for multisegment 10 Mb/s baseband networks
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definition: an electrical connection between networked devices.
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103:(collisions domains) and FOIRL links. The rules do not apply to
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87:The rules were created when 10BASE5, 10BASE2 and
80:An alternate configuration rule, known as the
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332:, Florida Center for Instructional Technology
224:. IEEE 802.3. 8 December 2012. Archived from
8:
378:
364:
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349:IEEE 802.3-2003 section 7.2.3.2 "Preamble"
44:computer networks covering the number of
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329:An Educator's Guide to School Networks
171:repeaters, or repeater hubs, and only
274:from the original on 6 December 2010.
7:
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255:from the original on 18 August 2010.
247:Helmig, Johannes (28 October 1997).
73:link segments (without senders) and
441:200, 400, 800 and 1600 Gbit/s
25:
128:For the purposes of this rule, a
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769:
768:
286:13.4 Transmission System Model 2
163:there can only be a maximum of
95:Ethernet segments connected by
1:
27:Design guideline for Ethernet
249:"Large Networks: 5-4-3 Rule"
167:segments, connected through
40:, is a design guideline for
18:Ethernet Way versus IEEE Way
825:
313:, IEEE, 26 December 2008,
132:is in accordance with the
52:on shared-medium Ethernet
36:, also referred to as the
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251:. WindowsNetworking.com.
691:SFP/SFP+/QSFP/QSFP+/OSFP
436:40 and 100 Gbit/s
69:rule with there being
431:25 and 50 Gbit/s
421:2.5 and 5 Gbit/s
153:twisted-pair Ethernet
121:designed to minimize
60:. It means that in a
268:"The 5-4-3-2-1 Rule"
179:Preamble consumption
266:Mitchell, Bradley.
116:Collision detection
391:local area network
228:on 5 December 2012
123:transmission times
77:collision domain.
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795:
648:Energy Efficiency
503:Ethernet Alliance
218:"IEEE 802.3-2012
105:switched Ethernet
16:(Redirected from
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462:Autonegotiation
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149:mixing segment
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491:Organizations
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270:. About.com.
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185:0101 preamble
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101:repeater hubs
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59:
58:tree topology
55:
51:
47:
43:
39:
35:
30:
19:
785:
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678:Transceivers
621:Applications
524:Twisted pair
472:Flow control
393:technologies
345:
334:, retrieved
328:
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314:
310:
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230:. Retrieved
226:the original
219:
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198:51.2 Ξs
194:
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151:. On modern
148:
138:
129:
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86:
82:Ethernet way
81:
79:
74:
70:
66:
37:
33:
31:
29:
668:Synchronous
643:Data center
336:4 September
309:"1.4.318",
296:IEEE 802.3
284:IEEE 802.3
232:15 November
157:end station
719:Interfaces
653:Industrial
633:Automotive
612:Long Reach
534:First mile
498:IEEE 802.3
389:family of
204:References
34:5-4-3 rule
607:LattisNet
602:100BaseVG
577:10BASE-FL
572:10BASE-FB
567:10BROAD36
467:EtherType
97:repeaters
67:5-4-3-2-1
54:backbones
46:repeaters
809:Ethernet
803:Category
775:Category
550:Historic
539:10G-EPON
387:Ethernet
272:Archived
253:Archived
50:segments
42:Ethernet
38:IEEE way
787:Commons
638:Carrier
587:10BASE2
582:10BASE5
562:StarLAN
557:CSMA/CD
529:Coaxial
450:General
145:10BASE2
141:10BASE5
130:segment
111:Details
696:XENPAK
482:Jumbos
477:Frames
399:Speeds
751:XGMII
663:Power
658:Metro
628:Audio
597:FOIRL
519:Fiber
512:Media
173:three
89:FOIRL
56:in a
756:XAUI
746:GMII
686:GBIC
338:2010
234:2015
169:four
165:five
143:and
134:IEEE
48:and
32:The
741:MII
736:MDI
731:EAD
726:AUI
710:CFP
705:XFP
592:MAU
99:or
75:one
71:two
805::
700:X2
698:/
379:e
372:t
365:v
236:.
222:"
20:)
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