Go Back   AnandTech Forums > Hardware and Technology > Networking

Forums
· Hardware and Technology
· CPUs and Overclocking
· Motherboards
· Video Cards and Graphics
· Memory and Storage
· Power Supplies
· Cases & Cooling
· SFF, Notebooks, Pre-Built/Barebones PCs
· Networking
· Peripherals
· General Hardware
· Highly Technical
· Computer Help
· Home Theater PCs
· Consumer Electronics
· Digital and Video Cameras
· Mobile Devices & Gadgets
· Audio/Video & Home Theater
· Software
· Software for Windows
· All Things Apple
· *nix Software
· Operating Systems
· Programming
· PC Gaming
· Console Gaming
· Distributed Computing
· Security
· Social
· Off Topic
· Politics and News
· Discussion Club
· Love and Relationships
· The Garage
· Health and Fitness
· Merchandise and Shopping
· For Sale/Trade
· Hot Deals with Free Stuff/Contests
· Black Friday 2013
· Forum Issues
· Technical Forum Issues
· Personal Forum Issues
· Suggestion Box
· Moderator Resources
· Moderator Discussions
   

Reply
 
Thread Tools
Old 11-30-2012, 08:22 PM   #1
alfa147x
Lifer
 
alfa147x's Avatar
 
Join Date: Jul 2005
Location: Georgia
Posts: 29,844
Question Networking hub. Does no one sell them anymore?

I remember seeing a lot of discussion a few years ago about switches vs hubs. The reasoning for switches is that they only send devices the data meant for them.

I'm trying to put something between a HP MSM313 and a cisco switch to allow me to hook up one temporary device. The network admin said to go ahead as long as it doesn't cause any issues with their setup.
I'm thinking if I get a hub vs a switch it'll be less interruptive. Thoughts?

The network admin told me we should be able to test a small unmanaged gigabit switch on Monday. Just trying to brainstorm alternative ideas.

Thanks!
__________________
.
alfa147x is offline   Reply With Quote
Old 11-30-2012, 08:43 PM   #2
VirtualLarry
Lifer
 
VirtualLarry's Avatar
 
Join Date: Aug 2001
Posts: 25,079
Default

Do you need to monitor/log/sample the data going over a port, or to just add a spare port somewhere to plug in an additional device? If you just need to add a port, then any old unmanaged switch would work.
__________________
Rig(s) not listed, because I change computers, like some people change their socks.
ATX is for poor people. And 'gamers.' - phucheneh
haswell is bulldozer... - aigomorla
"DON'T BUY INTEL, they will send secret signals down the internet, which
will considerably slow down your computer". - SOFTengCOMPelec
VirtualLarry is offline   Reply With Quote
Old 11-30-2012, 08:56 PM   #3
alfa147x
Lifer
 
alfa147x's Avatar
 
Join Date: Jul 2005
Location: Georgia
Posts: 29,844
Default

Quote:
Originally Posted by VirtualLarry View Post
Do you need to monitor/log/sample the data going over a port, or to just add a spare port somewhere to plug in an additional device? If you just need to add a port, then any old unmanaged switch would work.
No monitoring / log / sampling (Not that I need to do that. But a managed switch would do that. Right? )

That's what I thought. I had a unmanaged gigabit switch in and a few weeks later they started having "backlogging" problems (Not from the network admin. I think the guy is an intern or assistant). So the admin had me remove the switch and wait till monday to see if the issue continues.

Does backlogging due to a switch make any sense? It seems from my short conversations with these guys that they are CATV and Telcom guys.
__________________
.

Last edited by alfa147x; 11-30-2012 at 08:58 PM.
alfa147x is offline   Reply With Quote
Old 12-01-2012, 02:10 AM   #4
theevilsharpie
Platinum Member
 
Join Date: Nov 2009
Location: Southern California
Posts: 2,313
Default

No mainstream networking vendor sells hubs anymore, and there's very few reasons why you'd want one. You may be able to get them from a specialty manufacturer somewhere, but I can't think of any offhand.

I have no idea what "backlogging" is.
theevilsharpie is offline   Reply With Quote
Old 12-01-2012, 07:06 AM   #5
IndyColtsFan
Lifer
 
IndyColtsFan's Avatar
 
Join Date: Sep 2007
Location: Indianapolis
Posts: 28,713
Default

Quote:
Originally Posted by alfa147x View Post
No monitoring / log / sampling (Not that I need to do that. But a managed switch would do that. Right? )
Yes, a managed switch with port mirroring would allow you to monitor traffic on specific ports if that's what you need.

Quote:
That's what I thought. I had a unmanaged gigabit switch in and a few weeks later they started having "backlogging" problems (Not from the network admin. I think the guy is an intern or assistant). So the admin had me remove the switch and wait till monday to see if the issue continues.

Does backlogging due to a switch make any sense? It seems from my short conversations with these guys that they are CATV and Telcom guys.
Here is a definition of backlogging:

Quote:
Switches can also generate backpressureto cause transmitting devices to wait long enough for the switch to deal with backlogged traffic. To create backpressure, the switch broadcasts false collision detection signals to cause network interface cards to back off. It is ironic that switches must sometimes mimic the CSMA/CD access methodology that they negate.
So what he is saying is that he thinks your switch was bogging down under high traffic load and was slowing the network segment down.
__________________
MAIN: i7-2600K @ 4.5 Ghz | Asus P8Z68-V Pro | G.Skill 16 GB DDR3-1600 | Seagate 600 series 240 GB SSD (boot) | Samsung Evo 500 GB | 2 TB (data) | MSI Lightning GTX780 | Cosmos S | Dell U2410 and 2001fp | Seasonic Platinum 760 | Windows 8.1 x64 Enterprise

Last edited by IndyColtsFan; 12-01-2012 at 07:08 AM.
IndyColtsFan is online now   Reply With Quote
Old 12-01-2012, 07:43 AM   #6
Tsavo
Platinum Member
 
Tsavo's Avatar
 
Join Date: Sep 2009
Posts: 2,268
Default

Quote:
Originally Posted by theevilsharpie View Post
I have no idea what "backlogging" is.
Assists in forensic backtracing.

__________________
i5-3570K, i5-750. i5-2410M. i3-2100/2120.
Tsavo is offline   Reply With Quote
Old 12-01-2012, 09:24 AM   #7
unokitty
Platinum Member
 
Join Date: Jan 2012
Posts: 2,359
Default

Quote:
Originally Posted by alfa147x View Post
I'm trying to put something between a HP MSM313 and a cisco switch to allow me to hook up one temporary device. The network admin said to go ahead as long as it doesn't cause any issues with their setup.
I'm thinking if I get a hub vs a switch it'll be less interruptive. Thoughts?

Thanks!

Have you considered a network tap?

Uno
unokitty is offline   Reply With Quote
Old 12-01-2012, 11:04 AM   #8
Nothinman
Elite Member
 
Nothinman's Avatar
 
Join Date: Sep 2001
Posts: 30,672
Default

Quote:
Originally Posted by alfa147x View Post
I remember seeing a lot of discussion a few years ago about switches vs hubs. The reasoning for switches is that they only send devices the data meant for them.

I'm trying to put something between a HP MSM313 and a cisco switch to allow me to hook up one temporary device. The network admin said to go ahead as long as it doesn't cause any issues with their setup.
I'm thinking if I get a hub vs a switch it'll be less interruptive. Thoughts?

The network admin told me we should be able to test a small unmanaged gigabit switch on Monday. Just trying to brainstorm alternative ideas.

Thanks!
You'll be interrupting the MSM regardless of the device you choose since you'll have to unplug it for a second. Besides that, the only other issue I can think of right now would be a loop caused by you plugging the new switch back into the network via 2 ports. And that could be bad regardless of whether it's a hub or switch.
__________________
http://www.debian.org
Nothinman is offline   Reply With Quote
Old 12-01-2012, 11:51 AM   #9
theevilsharpie
Platinum Member
 
Join Date: Nov 2009
Location: Southern California
Posts: 2,313
Default

Quote:
Originally Posted by IndyColtsFan View Post
Quote:
Switches can also generate backpressureto cause transmitting devices to wait long enough for the switch to deal with backlogged traffic. To create backpressure, the switch broadcasts false collision detection signals to cause network interface cards to back off. It is ironic that switches must sometimes mimic the CSMA/CD access methodology that they negate.
So what he is saying is that he thinks your switch was bogging down under high traffic load and was slowing the network segment down.
Modern full-duplex Ethernet doesn't use CSMA/CD at all. If a switch interface is at capacity and its buffers are full, it will start dropping frames, or it will send out PAUSE frames if flow control is enabled.
theevilsharpie is offline   Reply With Quote
Old 12-01-2012, 01:30 PM   #10
alfa147x
Lifer
 
alfa147x's Avatar
 
Join Date: Jul 2005
Location: Georgia
Posts: 29,844
Default

The switch I used initially has 128 KB Buffer Memory

These two have more. Would I be work while upgrading to the hp?
144 KB (Rosewill RC-409LX)
512 KB (HP V1810-8G)

Quote:
Originally Posted by Nothinman View Post
You'll be interrupting the MSM regardless of the device you choose since you'll have to unplug it for a second. Besides that, the only other issue I can think of right now would be a loop caused by you plugging the new switch back into the network via 2 ports. And that could be bad regardless of whether it's a hub or switch.
I'm confused. Why is the new switch being connected to the network with two ports vs just one?
__________________
.
alfa147x is offline   Reply With Quote
Old 12-01-2012, 02:22 PM   #11
theevilsharpie
Platinum Member
 
Join Date: Nov 2009
Location: Southern California
Posts: 2,313
Default

You're overthinking this. If you're out of Ethernet ports and need to connect an additional device, just plug in a small switch and plug your devices into it. A 5-port Gigabit Ethernet switch is cheap and you can get them from pretty much any vendor that sells consumer electronics devices.
theevilsharpie is offline   Reply With Quote
Old 12-01-2012, 03:06 PM   #12
alfa147x
Lifer
 
alfa147x's Avatar
 
Join Date: Jul 2005
Location: Georgia
Posts: 29,844
Default

Quote:
Originally Posted by theevilsharpie View Post
You're overthinking this. If you're out of Ethernet ports and need to connect an additional device, just plug in a small switch and plug your devices into it. A 5-port Gigabit Ethernet switch is cheap and you can get them from pretty much any vendor that sells consumer electronics devices.
Right. I have plenty of those. But this is the issue I was trying to solve:

Quote:
Originally Posted by IndyColtsFan View Post
So what he is saying is that he thinks your switch was bogging down under high traffic load and was slowing the network segment down.
Quote:
Originally Posted by theevilsharpie View Post
Modern full-duplex Ethernet doesn't use CSMA/CD at all. If a switch interface is at capacity and its buffers are full, it will start dropping frames, or it will send out PAUSE frames if flow control is enabled.
__________________
.
alfa147x is offline   Reply With Quote
Old 12-01-2012, 03:20 PM   #13
Red Squirrel
Lifer
 
Red Squirrel's Avatar
 
Join Date: May 2003
Location: Canada
Posts: 26,514
Default

Another issue is trying to find a hub that is gigabit, did they ever even make those? You can probably ask them to mirror a port, that should allow you to plug a laptop with wireshark or do whatever it is that requires a hub. If you just want extra ports then a cheap switch is fine.
__________________
~Red Squirrel~
486dx2 @66Mhz turbo, 8MB ram, 512MB HDD, sound blaster 16 + 2x cdrom, Trident 1MB video card @ 640*480, 56k high speed modem.
Red Squirrel is offline   Reply With Quote
Old 12-01-2012, 03:41 PM   #14
alfa147x
Lifer
 
alfa147x's Avatar
 
Join Date: Jul 2005
Location: Georgia
Posts: 29,844
Default

Quote:
Originally Posted by Red Squirrel View Post
Another issue is trying to find a hub that is gigabit, did they ever even make those? You can probably ask them to mirror a port, that should allow you to plug a laptop with wireshark or do whatever it is that requires a hub. If you just want extra ports then a cheap switch is fine.
Apparently the gigabit spec doesn't allow hubs due to latency.
__________________
.
alfa147x is offline   Reply With Quote
Old 12-02-2012, 06:14 PM   #15
Danimal1209
Senior Member
 
Join Date: Nov 2011
Posts: 343
Default

If a switch is causing too much lag, for some reason, then a hub would not help. It would create more traffic since it is such a dumb device.

A hub sends out all frames it receives out every interface. a switch contains a MAC table so it will only send out the proper port, reducing traffic.
Danimal1209 is offline   Reply With Quote
Old 12-02-2012, 10:33 PM   #16
Red Squirrel
Lifer
 
Red Squirrel's Avatar
 
Join Date: May 2003
Location: Canada
Posts: 26,514
Default

Quote:
Originally Posted by alfa147x View Post
Apparently the gigabit spec doesn't allow hubs due to latency.
Makes sense, imagine the collisions when actually pushing gigabit speeds.

It would be jamming more than a rock concert.
__________________
~Red Squirrel~
486dx2 @66Mhz turbo, 8MB ram, 512MB HDD, sound blaster 16 + 2x cdrom, Trident 1MB video card @ 640*480, 56k high speed modem.
Red Squirrel is offline   Reply With Quote
Old 12-03-2012, 10:25 AM   #17
alfa147x
Lifer
 
alfa147x's Avatar
 
Join Date: Jul 2005
Location: Georgia
Posts: 29,844
Default

Just had a voicemail left. It's a no go. He said something about adding a switch causing back feed. Anyone know anything about that?
The only thing I can find is feeding power back back into the grid.

Thanks for the help.

Edit: I'm pretty sure at this point they don't want us hooking stuff up but don't have a good excuse. If someone can verify that "back feed" is bullshit I'll just escalate it to my boss and have him take care of it (if needed have a new drop run)
__________________
.

Last edited by alfa147x; 12-03-2012 at 10:33 AM.
alfa147x is offline   Reply With Quote
Old 12-03-2012, 10:34 AM   #18
alfa147x
Lifer
 
alfa147x's Avatar
 
Join Date: Jul 2005
Location: Georgia
Posts: 29,844
Default

Quote:
Originally Posted by Red Squirrel View Post
Makes sense, imagine the collisions when actually pushing gigabit speeds.

It would be jamming more than a rock concert.
Lol
__________________
.
alfa147x is offline   Reply With Quote
Old 12-03-2012, 10:39 AM   #19
Spicedaddy
Platinum Member
 
Spicedaddy's Avatar
 
Join Date: Apr 2002
Posts: 2,087
Default

Are they using PoE (power over ethernet) for the MSM313 access point?
Spicedaddy is offline   Reply With Quote
Old 12-03-2012, 10:50 AM   #20
alfa147x
Lifer
 
alfa147x's Avatar
 
Join Date: Jul 2005
Location: Georgia
Posts: 29,844
Default

Quote:
Originally Posted by Spicedaddy View Post
Are they using PoE (power over ethernet) for the MSM313 access point?
Yes. But they have a Dc adapter near by for backup. Also we have a HP JD483B#ABA PoE Injector.

The Dc adapter is Oem.

Would either one cause back feed ?

I feel stupid for to even thinking one of them could cause an issue. Any idea how to verify?
__________________
.

Last edited by alfa147x; 12-03-2012 at 10:59 AM.
alfa147x is offline   Reply With Quote
Old 12-03-2012, 11:36 AM   #21
theevilsharpie
Platinum Member
 
Join Date: Nov 2009
Location: Southern California
Posts: 2,313
Default

Quote:
Originally Posted by alfa147x View Post
Edit: I'm pretty sure at this point they don't want us hooking stuff up but don't have a good excuse. If someone can verify that "back feed" is bullshit I'll just escalate it to my boss and have him take care of it (if needed have a new drop run)
I have no idea what either "backlogging" or "backfeed" are. Either the network admin is blowing smoke up your ass, or he is actually having a problem but isn't expressing it in industry-standard terminology.

Ask for specifics.
theevilsharpie is offline   Reply With Quote
Old 12-04-2012, 09:51 AM   #22
ScottMac
Moderator
Networking
Elite member
 
Join Date: Mar 2001
Posts: 5,471
Default

Quote:
Originally Posted by alfa147x View Post
Apparently the gigabit spec doesn't allow hubs due to latency.
Hubs have virtually no latency; they are repeaters. Latency is added by the store & forward technology commonly used in switches these days. Cut-through switches added only a little latency, but don't really permit the advanced features that a store & forward switch offers.

There are no Gig hubs because technology was well past hubs when gig was introduced.
__________________
Eschew Obfuscation! Espouse Elucidation!

Optimists are never pleasantly surprised.

Nov 4th, 2008: History is made: - Richie Daley becomes the first Mayor in history with his own pet President.
ScottMac is offline   Reply With Quote
Old 12-04-2012, 12:36 PM   #23
mammador
Golden Member
 
mammador's Avatar
 
Join Date: Dec 2010
Posts: 1,839
Default

Hubs are a 1980s technology.

I think now that most networked nodes need a dedicated communications path, hubs went out long ago.

If one has a network of a server, a printer, several desktops, and a couple of cameras, collisions are a no-no. I'm also surprised that CCNA still teaches students about hubs, it's not something most networking professional will apply in an enterprise or even home setting.
__________________
Man is the measure of all things, the key is to find one's own measure.

thumbs up for all people like her
mammador is offline   Reply With Quote
Old 12-04-2012, 04:23 PM   #24
Red Squirrel
Lifer
 
Red Squirrel's Avatar
 
Join Date: May 2003
Location: Canada
Posts: 26,514
Default

Heck CCNA still teaches about thinnet and thicknet lol. It's like A+ and having to know IRQs or details on 486 processors (number of pins etc), I don't get why these tests cover such old concepts that are not really needed to be known off hand in the real world.
__________________
~Red Squirrel~
486dx2 @66Mhz turbo, 8MB ram, 512MB HDD, sound blaster 16 + 2x cdrom, Trident 1MB video card @ 640*480, 56k high speed modem.
Red Squirrel is offline   Reply With Quote
Old 12-04-2012, 04:48 PM   #25
Nothinman
Elite Member
 
Nothinman's Avatar
 
Join Date: Sep 2001
Posts: 30,672
Default

Quote:
Originally Posted by Red Squirrel View Post
Heck CCNA still teaches about thinnet and thicknet lol. It's like A+ and having to know IRQs or details on 486 processors (number of pins etc), I don't get why these tests cover such old concepts that are not really needed to be known off hand in the real world.
Did you take your CCNA recently? Because I don't remember seeing anything in the 640-802 exam specifically about thicknet in the book I have here. Hubs and such are covered because it's the best way to show why switching was introduced and the advantages it provides.
__________________
http://www.debian.org
Nothinman is offline   Reply With Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 01:53 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.