Hi All,
Not to ask too silly a question, but what happens when you have dual Ethernet adapters and you hook both of them to your (switching) hub?
You go twice as fast?
Many thanks, -T Tony Ewell, B.S.E.E. Owner, Rent-A-Nerd Computer Services 775-265-5150, 9:00 am to 5:00 pm PST/PDT
On Wed, 6 May 2020 15:02:08 -0700 ToddAndMargo via users wrote:
Not to ask too silly a question, but what happens when you have dual Ethernet adapters and you hook both of them to your (switching) hub?
Mostly you need something that supports "bonding" to go faster. As near as I can tell, 99.9% of all traffic always goes through one ethernet if they are both configured on the same subnet.
On 2020-05-06 15:11, Tom Horsley wrote:
On Wed, 6 May 2020 15:02:08 -0700 ToddAndMargo via users wrote:
Not to ask too silly a question, but what happens when you have dual Ethernet adapters and you hook both of them to your (switching) hub?
Mostly you need something that supports "bonding" to go faster. As near as I can tell, 99.9% of all traffic always goes through one ethernet if they are both configured on the same subnet.
Would I have to bond at both the Lixux side and the switching hub side?
On 5/6/20 3:45 PM, ToddAndMargo via users wrote:
On 2020-05-06 15:11, Tom Horsley wrote:
On Wed, 6 May 2020 15:02:08 -0700 ToddAndMargo via users wrote:
Not to ask too silly a question, but what happens when you have dual Ethernet adapters and you hook both of them to your (switching) hub?
Mostly you need something that supports "bonding" to go faster. As near as I can tell, 99.9% of all traffic always goes through one ethernet if they are both configured on the same subnet.
Would I have to bond at both the Lixux side and the switching hub side?
Yes, the switch has to understand the bonding or you can get very interesting results.
On 2020-05-06 15:55, Samuel Sieb wrote:
Would I have to bond at both the Lixux side and the switching hub side?
Yes, the switch has to understand the bonding or you can get very interesting results.
And I presume the hub have to be twice as fast as your Ethernet cards to take advantage of it.
On 5/6/20 8:13 PM, ToddAndMargo via users wrote:
On 2020-05-06 15:55, Samuel Sieb wrote:
Would I have to bond at both the Lixux side and the switching hub side?
Yes, the switch has to understand the bonding or you can get very interesting results.
And I presume the hub have to be twice as fast as your Ethernet cards to take advantage of it.
Most switches advertise that they can handle full duplex on all ports at once, so it's not the switch bandwidth that's the problem. It's whatever you're connecting to. If you try to download from another computer with only one network card, that's all you'll get. This is more for servers where there are multiple clients trying to get data at the same time or for a computer that is downloading from multiple locations at once on the local network.
If it is a really dumb switch you don't need a bond on the switch. In my experience most simple switches can move the mac address from one port to another so fast that without bonding setup it will act as round-robin on the switch end (if linux is setup round-robin). On the better managed switches it will detect the mac address existing on both ports and complain and/or disable a port. The high volume of complaining will cause the management processor to work hard. On newer software defined switches they will generally have issues trying to move the mac addresses around as on a virtual switch (many switches acting like one) that has to be done in software and won't be able to keep up.
So put the linux machine in round-robin bonding mode, and connect to switch. Do some testing and see how much bandwidth you can get, if you exceed about 130Mbytes/sec on a dual gb link then it is probably working. You should be able to see the amount of data going over each interface with sar -n DEV (install sysstat) and google how to change it sampling rate down to 1minute. Note with nfs and/or disk access being involved you may not be able to sustain anywhere close to that rate. When I have tested my gbit setup I almost never get anywhere close to the rate even when I am trying, so it might be best to install sar and see if you are getting anywhere close to 1gbit now. If you have a switch that supports lacp/802 something then setup both sides of the bond to lacp/802* with layer3+4 routing on the linux end.
On Wed, May 6, 2020 at 5:48 PM ToddAndMargo via users users@lists.fedoraproject.org wrote:
On 2020-05-06 15:11, Tom Horsley wrote:
On Wed, 6 May 2020 15:02:08 -0700 ToddAndMargo via users wrote:
Not to ask too silly a question, but what happens when you have dual Ethernet adapters and you hook both of them to your (switching) hub?
Mostly you need something that supports "bonding" to go faster. As near as I can tell, 99.9% of all traffic always goes through one ethernet if they are both configured on the same subnet.
Would I have to bond at both the Lixux side and the switching hub side? _______________________________________________ users mailing list -- users@lists.fedoraproject.org To unsubscribe send an email to users-leave@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/users@lists.fedoraproject.org
On 5/6/20 3:02 PM, ToddAndMargo via users wrote:
Not to ask too silly a question, but what happens when you have dual Ethernet adapters and you hook both of them to your (switching) hub?
You go twice as fast?
Only if you have a smart switch that does bonding or trunking. Then you can configure a bonded interface across both and it will load balance. Otherwise, you will get a different IP address on each one and one of them will be the default and the other won't be used.
On 2020-05-06 15:14, Samuel Sieb wrote:
On 5/6/20 3:02 PM, ToddAndMargo via users wrote:
Not to ask too silly a question, but what happens when you have dual Ethernet adapters and you hook both of them to your (switching) hub?
You go twice as fast?
Only if you have a smart switch that does bonding or trunking. Then you can configure a bonded interface across both and it will load balance. Otherwise, you will get a different IP address on each one and one of them will be the default and the other won't be used.
Hi Sam,
Perfect explanation. Thank you
-T
On 2020-05-06 6:02 p.m., ToddAndMargo via users wrote:
Hi All,
Not to ask too silly a question, but what happens when you have dual Ethernet adapters and you hook both of them to your (switching) hub?
You go twice as fast?
Many thanks,
Yes and no...
There's seven bonding modes, six of which aggregate bandwidth in various ways (one, mode=1, is focused on reliability). So with those, you'll double your bandwidth.
Of course, this is bandwidth to the switch (point of order, "hub" is an old style that shares bandwidth to all ports, modern switches are per port). If you've got data coming/going from more that one source, you'll potentially benefit, but between two machines, you'll need the other machine to also have enough bandwidth as connections always go at the slowest link.
On 2020-05-06 15:15, Digimer wrote:
On 2020-05-06 6:02 p.m., ToddAndMargo via users wrote:
Hi All,
Not to ask too silly a question, but what happens when you have dual Ethernet adapters and you hook both of them to your (switching) hub?
You go twice as fast?
Many thanks,
Yes and no...
There's seven bonding modes, six of which aggregate bandwidth in various ways (one, mode=1, is focused on reliability). So with those, you'll double your bandwidth.
Of course, this is bandwidth to the switch (point of order, "hub" is an old style that shares bandwidth to all ports, modern switches are per port). If you've got data coming/going from more that one source, you'll potentially benefit, but between two machines, you'll need the other machine to also have enough bandwidth as connections always go at the slowest link.
Thank you. Good explanation.
By the way, both are hubs. "switch" is a short name for a type of hub.
https://en.wikipedia.org/wiki/Network_switch
A network switch (also called switching hub, bridging hub, officially MAC bridge)[1] is networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device.
I use the word "hub" because it is proper English:
https://www.merriam-webster.com/dictionary/hub 1 : the central part of a circular object (such as a wheel or propeller) spokes attached to the hub of the wheel
2a : a center of activity : focal point The island is a major tourist hub.
b : an airport or city through which an airline routes most of its traffic
c : a central device that connects multiple computers on a single network (see network entry 1 sense 3b)
And since not everyone know the difference, I put "Switching" in parenthesis.
"Level 3" would also be short for "level 3 switching hub"
-T
On 5/6/20 3:44 PM, ToddAndMargo via users wrote:
By the way, both are hubs. "switch" is a short name for a type of hub.
I suppose that's correct, but it's terminology that's not used now. If you say "hub" to someone that's too young to have actually used one, they most likely won't know what you're talking about. They're just switches now.
On 2020-05-06 15:58, Samuel Sieb wrote:
On 5/6/20 3:44 PM, ToddAndMargo via users wrote:
By the way, both are hubs. "switch" is a short name for a type of hub.
I suppose that's correct, but it's terminology that's not used now. If you say "hub" to someone that's too young to have actually used one, they most likely won't know what you're talking about. They're just switches now.
True. That is why I put "switch" in there somewhere so they can figure out what I am talking about.
With my customers I always use the word "hub" as that they understand. To them "switch" is what they turn their lights on and off with.
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Digimer -
Roger Heflin -
Samuel Sieb -
ToddAndMargo -
Tom Horsley