Hub / Switch daisy chaining limitation
What is the number of daisy chaining limitation for hubs and for switches? Please include a supporting link as well.
Thank you
Thank you
I always thought the limit was 4...I'll see if I can find some links that verify one way or the other...
Check out the "5-4-3" Rule...
http://www.optronics.gr/Tutorials/ethernet.htm
I remember learning about this in a networking class way back...for some reason 4 repeaters was stuck in my head.
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According to the IEEE 802.3 specifications, a network using repeaters between communicating stations (PCs) is subject to the "5-4-3" rule of repeater placement on the network:
5 segments - connected on the network
4 repeaters
3 segments - of the 5 segments can have stations connected. The other two segments must be inter-repeater link segments with no stations connected.
http://www.optronics.gr/Tutorials/ethernet.htm
I remember learning about this in a networking class way back...for some reason 4 repeaters was stuck in my head.
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According to the IEEE 802.3 specifications, a network using repeaters between communicating stations (PCs) is subject to the "5-4-3" rule of repeater placement on the network:
5 segments - connected on the network
4 repeaters
3 segments - of the 5 segments can have stations connected. The other two segments must be inter-repeater link segments with no stations connected.
Carefully read the packaging also. I had purchsed several switches that had "Desktop" on them (3com desktop switches 10/100) that only allowed a total of 4 mac address per port, was a real pain troubleshooting why the distant switch only 3 people could log on at one time, heheh
Also, I believe the 543 rule only applies to 10base-T and not 100BASE-TX ??
"A switched Ethernet network should be exempt from the 5-4-3 rule because each switch has a buffer to temporarily store data and all nodes can access a switched Ethernet LAN simultaneously"
With the price so low, I would use nothing except switches unless their was a very specific reason to use a hub. For example to monitor incoming traffic I have a hub setup just inside my router, before my firewall, and my monitoring device is also connected to the hub so it can watch traffic flow by.
Also, I believe the 543 rule only applies to 10base-T and not 100BASE-TX ??
"A switched Ethernet network should be exempt from the 5-4-3 rule because each switch has a buffer to temporarily store data and all nodes can access a switched Ethernet LAN simultaneously"
With the price so low, I would use nothing except switches unless their was a very specific reason to use a hub. For example to monitor incoming traffic I have a hub setup just inside my router, before my firewall, and my monitoring device is also connected to the hub so it can watch traffic flow by.
Daisy chain one connected to another is no recommended if you can avoid it. If you must have several switches/hubs to have a 1-2 central switches and have all the connections come back to these.
-= Felix =-
-= Felix =-
Mazaraat, it's funny...that's a contradiction...the quote you pulled refers to a "switched network", yet the rule applies to a switched network, hence the "4 - switch" part of the rule.
I don't know for sure, but I think it's just "good practice" to follow the 5-4-3 rule. Depending on your specific hardware use, this rule may be bent in favor of more or less switches depending on the quality of the hardware. You are likely not going to be able to uplink 5 $30 switches and get the same kind of single at the other end than with 5 $2000 switches. I think the rule is in place because for *most* networks, this will enable a reliable data transfer.
I don't know for sure, but I think it's just "good practice" to follow the 5-4-3 rule. Depending on your specific hardware use, this rule may be bent in favor of more or less switches depending on the quality of the hardware. You are likely not going to be able to uplink 5 $30 switches and get the same kind of single at the other end than with 5 $2000 switches. I think the rule is in place because for *most* networks, this will enable a reliable data transfer.
The 5-4-3 rule applies to a single collision domain. Switches start a new collision domain on each port, so the 5-4-3 rule does not apply to ethernet. There are no bonus points for following the 5-4-3 rule when switching.
-Eric
-Eric
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On this CCNA website I found that this might be some useful information:
"The IEEE 802.3u specification for 100BaseTX networks allows a maximum of two repeater (hub) networks and a total network diameter of approximately 200 meters. A link segment, which is defined as a point-to-point connection between two Medium Independent Interface (MII) devices, can be up to 100 meters."
http://netcert.tripod.com/ccna/internetworking/enetworking.html
"The IEEE 802.3u specification for 100BaseTX networks allows a maximum of two repeater (hub) networks and a total network diameter of approximately 200 meters. A link segment, which is defined as a point-to-point connection between two Medium Independent Interface (MII) devices, can be up to 100 meters."
http://netcert.tripod.com/ccna/internetworking/enetworking.html
Yes. This is correct. I was a little lazy in putting out the exact spec.
This essentially says the same thing. If you have a stackable hub system,
a packet goes into one unit, passes the inter-repeater link, and goes out
from another unit, it essentially passes through two hubs. The spec actually tries
to keep the user link segment to consistent 100 meters. The little more
than 200 meters includes the short inter-repeater link cable.
From user's point of view, you see a stackable hub and think it is a
single hub. You can only have every user segment 100 meters, but you
can not link to any other hub with just a link cable. Every other
network device linked to this hub has to be bridges.
This essentially says the same thing. If you have a stackable hub system,
a packet goes into one unit, passes the inter-repeater link, and goes out
from another unit, it essentially passes through two hubs. The spec actually tries
to keep the user link segment to consistent 100 meters. The little more
than 200 meters includes the short inter-repeater link cable.
From user's point of view, you see a stackable hub and think it is a
single hub. You can only have every user segment 100 meters, but you
can not link to any other hub with just a link cable. Every other
network device linked to this hub has to be bridges.
The post on 10/19 was the accepted answer. Am I missing something?
(sorry, I'm in training right now else I'd have more time to provide detailed links!).
THREE is the limit. Daisy chain any more than that, and you end up with packet loss.