slot time in binary backoff CSMA/CD
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In the binary backoff protocol, hosts will choose a random value between 0 to 2^n - 1 and multiply that number by the time it takes to transmit 512 bits. From wikipedia
Slot time is a concept in computer networking. It is at least twice the
time it takes for an electronic pulse (OSI Layer 1 - Physical) to
travel the length of the maximum theoretical distance between two n
odes. In CSMA/CD networks such as Ethernet, the slot time is an upper
limit on the acquisition of the medium, a limit on the length of a
packet fragment generated by a collision, and the scheduling quantum
for retransmission.[1]
I am not sure i get this fully, from the definition above, it is the time it takes for the signal to reach the furthest node in the link ?
if node A and B collides, and if its their first collision for both nodes, then they choose a random value 0 or 1 and multiply that by 512 bit time. So if node A chooses 0 and node B chooses 1, the slot time guarantees that node A will finish fully transmitting its frame before node B starts to transmit his frame, so that there is no chance of collision even when they have chosen consecutive values ?
networking ethernet collision-detection
asked Nov 24 at 2:34
calveeen
486
add a comment |
up vote
-1
down vote
favorite
In the binary backoff protocol, hosts will choose a random value between 0 to 2^n - 1 and multiply that number by the time it takes to transmit 512 bits. From wikipedia
Slot time is a concept in computer networking. It is at least twice the
time it takes for an electronic pulse (OSI Layer 1 - Physical) to
travel the length of the maximum theoretical distance between two n
odes. In CSMA/CD networks such as Ethernet, the slot time is an upper
limit on the acquisition of the medium, a limit on the length of a
packet fragment generated by a collision, and the scheduling quantum
for retransmission.[1]
I am not sure i get this fully, from the definition above, it is the time it takes for the signal to reach the furthest node in the link ?
if node A and B collides, and if its their first collision for both nodes, then they choose a random value 0 or 1 and multiply that by 512 bit time. So if node A chooses 0 and node B chooses 1, the slot time guarantees that node A will finish fully transmitting its frame before node B starts to transmit his frame, so that there is no chance of collision even when they have chosen consecutive values ?
networking ethernet collision-detection
asked Nov 24 at 2:34
calveeen
486
Is this a homework question from the 1990's? 100BASE-T is almost always switched (thus full duplex, no collisions), and 1000BASE-T doesn't allow hubs at all. The days of collisions on Ethernet mostly died at the end of the 20th century.
– Spiff
Nov 24 at 6:41
No its not a homework question. If ethernet does not use CSMA/CD then where is CSMA/CD being used today ? And why would full duplex mean no collisions ?
– calveeen
Nov 24 at 8:13
Every Ethernet device still knows how to do CSMA/CD even though it is almost never needed anymore due to the ubiquity of switches and the rarity of hubs. Full duplex means no collisions by definition. If you can't both transmit at the same time without a collision, how could that ever be considered full duplex?
– Spiff
Nov 24 at 18:32
add a comment |
up vote
-1
down vote
favorite
up vote
-1
down vote
favorite
In the binary backoff protocol, hosts will choose a random value between 0 to 2^n - 1 and multiply that number by the time it takes to transmit 512 bits. From wikipedia
Slot time is a concept in computer networking. It is at least twice the
time it takes for an electronic pulse (OSI Layer 1 - Physical) to
travel the length of the maximum theoretical distance between two n
odes. In CSMA/CD networks such as Ethernet, the slot time is an upper
limit on the acquisition of the medium, a limit on the length of a
packet fragment generated by a collision, and the scheduling quantum
for retransmission.[1]
I am not sure i get this fully, from the definition above, it is the time it takes for the signal to reach the furthest node in the link ?
if node A and B collides, and if its their first collision for both nodes, then they choose a random value 0 or 1 and multiply that by 512 bit time. So if node A chooses 0 and node B chooses 1, the slot time guarantees that node A will finish fully transmitting its frame before node B starts to transmit his frame, so that there is no chance of collision even when they have chosen consecutive values ?
networking ethernet collision-detection
asked Nov 24 at 2:34
calveeen
486
In the binary backoff protocol, hosts will choose a random value between 0 to 2^n - 1 and multiply that number by the time it takes to transmit 512 bits. From wikipedia
Slot time is a concept in computer networking. It is at least twice the
time it takes for an electronic pulse (OSI Layer 1 - Physical) to
travel the length of the maximum theoretical distance between two n
odes. In CSMA/CD networks such as Ethernet, the slot time is an upper
limit on the acquisition of the medium, a limit on the length of a
packet fragment generated by a collision, and the scheduling quantum
for retransmission.[1]
I am not sure i get this fully, from the definition above, it is the time it takes for the signal to reach the furthest node in the link ?
if node A and B collides, and if its their first collision for both nodes, then they choose a random value 0 or 1 and multiply that by 512 bit time. So if node A chooses 0 and node B chooses 1, the slot time guarantees that node A will finish fully transmitting its frame before node B starts to transmit his frame, so that there is no chance of collision even when they have chosen consecutive values ?
networking ethernet collision-detection
networking ethernet collision-detection
asked Nov 24 at 2:34
calveeen
486
asked Nov 24 at 2:34
calveeen
486
asked Nov 24 at 2:34
calveeen
486
asked Nov 24 at 2:34
calveeen
486
asked Nov 24 at 2:34
calveeen
486
486
Is this a homework question from the 1990's? 100BASE-T is almost always switched (thus full duplex, no collisions), and 1000BASE-T doesn't allow hubs at all. The days of collisions on Ethernet mostly died at the end of the 20th century.
– Spiff
Nov 24 at 6:41
No its not a homework question. If ethernet does not use CSMA/CD then where is CSMA/CD being used today ? And why would full duplex mean no collisions ?
– calveeen
Nov 24 at 8:13
Every Ethernet device still knows how to do CSMA/CD even though it is almost never needed anymore due to the ubiquity of switches and the rarity of hubs. Full duplex means no collisions by definition. If you can't both transmit at the same time without a collision, how could that ever be considered full duplex?
– Spiff
Nov 24 at 18:32
add a comment |
Is this a homework question from the 1990's? 100BASE-T is almost always switched (thus full duplex, no collisions), and 1000BASE-T doesn't allow hubs at all. The days of collisions on Ethernet mostly died at the end of the 20th century.
– Spiff
Nov 24 at 6:41
No its not a homework question. If ethernet does not use CSMA/CD then where is CSMA/CD being used today ? And why would full duplex mean no collisions ?
– calveeen
Nov 24 at 8:13
Every Ethernet device still knows how to do CSMA/CD even though it is almost never needed anymore due to the ubiquity of switches and the rarity of hubs. Full duplex means no collisions by definition. If you can't both transmit at the same time without a collision, how could that ever be considered full duplex?
– Spiff
Nov 24 at 18:32
Is this a homework question from the 1990's? 100BASE-T is almost always switched (thus full duplex, no collisions), and 1000BASE-T doesn't allow hubs at all. The days of collisions on Ethernet mostly died at the end of the 20th century.
– Spiff
Nov 24 at 6:41
Is this a homework question from the 1990's? 100BASE-T is almost always switched (thus full duplex, no collisions), and 1000BASE-T doesn't allow hubs at all. The days of collisions on Ethernet mostly died at the end of the 20th century.
– Spiff
Nov 24 at 6:41
No its not a homework question. If ethernet does not use CSMA/CD then where is CSMA/CD being used today ? And why would full duplex mean no collisions ?
– calveeen
Nov 24 at 8:13
No its not a homework question. If ethernet does not use CSMA/CD then where is CSMA/CD being used today ? And why would full duplex mean no collisions ?
– calveeen
Nov 24 at 8:13
Every Ethernet device still knows how to do CSMA/CD even though it is almost never needed anymore due to the ubiquity of switches and the rarity of hubs. Full duplex means no collisions by definition. If you can't both transmit at the same time without a collision, how could that ever be considered full duplex?
– Spiff
Nov 24 at 18:32
Every Ethernet device still knows how to do CSMA/CD even though it is almost never needed anymore due to the ubiquity of switches and the rarity of hubs. Full duplex means no collisions by definition. If you can't both transmit at the same time without a collision, how could that ever be considered full duplex?
– Spiff
Nov 24 at 18:32
add a comment |
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Is this a homework question from the 1990's? 100BASE-T is almost always switched (thus full duplex, no collisions), and 1000BASE-T doesn't allow hubs at all. The days of collisions on Ethernet mostly died at the end of the 20th century.
– Spiff
Nov 24 at 6:41
No its not a homework question. If ethernet does not use CSMA/CD then where is CSMA/CD being used today ? And why would full duplex mean no collisions ?
– calveeen
Nov 24 at 8:13
Every Ethernet device still knows how to do CSMA/CD even though it is almost never needed anymore due to the ubiquity of switches and the rarity of hubs. Full duplex means no collisions by definition. If you can't both transmit at the same time without a collision, how could that ever be considered full duplex?
– Spiff
Nov 24 at 18:32