Switch / Router question

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Hartlove

Limp Gawd
Joined
Aug 26, 2003
Messages
349
In my office I have a workstation, a webserver, a test box and a backup server all connected to an unmanaged switch, which is uplinked to my wall jack, which is connected to a switch. I'm not sure if that one is managed or not, but I think it is. My question though:

If I'm moving a few gigs of data between the webserver and the backup server, does the data go straight through my switch from box to box, or does it have to go through the uplink all the way up to a managed switch or a router and then come all the way back down the pipe?

The reason I ask is I have a couple of 100Mb NICs on my desk and I was wondering if setting up a seprate crossover network between the 2 boxes would speed things up any. Right now it takes at least a half hour to copy a 1 gig backup. (Both are 2.2 gig P4's with 512MB ram)
 
The data is going all the way back to the router first so yes, it would be faster if you set up a crossover network between the 2 computers.
 
Hartlove said:
In my office I have a workstation, a webserver, a test box and a backup server all connected to an unmanaged switch, which is uplinked to my wall jack, which is connected to a switch. I'm not sure if that one is managed or not, but I think it is. My question though:

If I'm moving a few gigs of data between the webserver and the backup server, does the data go straight through my switch from box to box, or does it have to go through the uplink all the way up to a managed switch or a router and then come all the way back down the pipe?

The reason I ask is I have a couple of 100Mb NICs on my desk and I was wondering if setting up a seprate crossover network between the 2 boxes would speed things up any. Right now it takes at least a half hour to copy a 1 gig backup. (Both are 2.2 gig P4's with 512MB ram)
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It depends on whether that managed switch hasVLANs configured on it. If it does, then your data will go from your workgroup switch to the managed switch to the router to be routed intervlan and then back down the pipe via a trunked link, unless the managed switch is a layer-3 switch, in which the scenario differs. The layer-3 switch, once it knows how to "route" that data, no longer needs the services of the router. If setting up a crossover network very easy for you to do, it might be more efficient as the source to destination would be the only two units on the network, considering the amount of data you are transferring impacts other users/machines on that workgroup. If the crossover network isn't a viable solution, I'd suggest limiting transfers of that volume to afterhours.

My $0.02.
 
Thanks for the help guys, I think thats what I'm going to do.

Should I anticipate any trouble with running the crossover network in conjunction with the regular network? I'm guessing that as long as I change my drive mappings between the boxes so that they point to each other using the new network instead of the old I'll be OK, right?

Out of curiosity, if I'm on the backup server, and I browse to \\webserver, how do I control which network is being used?
 
If your running a crossover to the machines direclty, they will not be connected to the network so you gain speed but you loose the ability to have them on the network to do stuff. Unless you like swapping cables I suggest limiting your transfers to after hours or upgrading your switches and NIC's to gigabit if your gonna pound on the lines that hard.

Also, are all your machines on the same IP subnet? If so, then your local unmanaged switch will send data to the correct port to the machine using the MAC address Layer 2 level and the switch and router on the other side will sit their and twiddle their thumbs. IF on the other hand your IP's are NOT on the same subnet, then yes, the traffic is being routed to the unmanagead switch ------>managed switched------router and then back again thereby hurting everyone on that network while your transfering those huge files.
 
Or, you could install an additional NIC in each machine, setup the crossover cable and setup a static IP scheme on the same subnet and disable the LAN connection to the main internetwork till you're done transferring the files. Of course, you'll have to map drives manually, but then when you're done you can just re-enable the main LAN connection and disable LAN 2 until you need to transfer files again.
 
Ok, check your IP's of the two machines. Nomar is assuming VLANs and different subnets. If your two machines are on the same subnet then they are talking directly too each other through the first switch. Your traffic never goes past that switch and you are not going to get a speed boost, not a noticeable one anyway. Well, let me correct that. Is the webserver serving a crap load of traffic? Are there other systems other than just yours connected to that switch? If there is a whole crap load of other traffic flowing through that switch, then directly connecting your two systems will speed things up.
 
OK, sorry for the long delay.

My machines are on the same subnet.

The webserver pretty much only serves me; it's just a development box, and all the other machines on that switch are used by only me, so they aren't generating traffice while I'm doing this, unless I'm downloading something.

I was hoping to add a second NIC like DVAmon was saying, but I didn't realize that a machine couldn't be on 2 networks at once, even with 2 NICs. If that's the case, I guess this whole thing is a moot point, and I'll just do homework while I wait for the transfers.

So, since the machines are on the same subnet, you're saying that the data never goes past the switch anyways?

A couple of you guys mentioned waiting until after hours to do these transfers. I try to be considerate to my office mates, and on the rare occasion that I'm in the office at regular hours, I do wait until things die down. Sometimes that seems difficult, since it seems almost everything I work on has gigantic files, but I try.

Thanks for the help so far guys, I just like to know how these things work as best as I can.
 
Hartlove said:
OK, sorry for the long delay.

My machines are on the same subnet.

The webserver pretty much only serves me; it's just a development box, and all the other machines on that switch are used by only me, so they aren't generating traffice while I'm doing this, unless I'm downloading something.

I was hoping to add a second NIC like DVAmon was saying, but I didn't realize that a machine couldn't be on 2 networks at once, even with 2 NICs. If that's the case, I guess this whole thing is a moot point, and I'll just do homework while I wait for the transfers.

So, since the machines are on the same subnet, you're saying that the data never goes past the switch anyways?

A couple of you guys mentioned waiting until after hours to do these transfers. I try to be considerate to my office mates, and on the rare occasion that I'm in the office at regular hours, I do wait until things die down. Sometimes that seems difficult, since it seems almost everything I work on has gigantic files, but I try.

Thanks for the help so far guys, I just like to know how these things work as best as I can.
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Correct, being on the same subnet means the data doesn' t have to be routed to the router to a different IP subnet and back and thus it says within your domain where your switch is for local traffic. Unless your doing internet transfering then yes, it goes through both switches to the router and back
 
A machine CAN be on two networks at once - what do you think a router does?

You could add the same NICs in the machine and statically assign it an IP address that is on a different network from your office network (i.e., your office uses 10.0.10.x for their network, you use 192.168.0.x for the NIC) and DO NOT ASSIGN IT A GATEWAY. What your computer MAY NOT have is multiple gateways.

After doing that, you can just connect via crossover and transfer to YOUR LOCAL IP, the 192.168.0.x address. Easy, you stay on the network, and you get a really fast connection between the computers you need.
 
ZeroX said:
A machine CAN be on two networks at once - what do you think a router does?

You could add the same NICs in the machine and statically assign it an IP address that is on a different network from your office network (i.e., your office uses 10.0.10.x for their network, you use 192.168.0.x for the NIC) and DO NOT ASSIGN IT A GATEWAY. What your computer MAY NOT have is multiple gateways.

After doing that, you can just connect via crossover and transfer to YOUR LOCAL IP, the 192.168.0.x address. Easy, you stay on the network, and you get a really fast connection between the computers you need.
Click to expand...

That's what I wanted to hear. Thanks ZeroX.

BTW: Do you live in CP, or just go to school there? I'm a student at UMUC, and most of my classes are on the CP campus.
 
I just graduated from UMD in May. I'm still living in CP right now but will be moving out at the end of the month.
 
IceWind said:
Correct, being on the same subnet means the data doesn' t have to be routed to the router to a different IP subnet and back and thus it says within your domain where your switch is for local traffic. Unless your doing internet transfering then yes, it goes through both switches to the router and back
Click to expand...

Glad you got your answer Hartlove, but I still have issue with what IceWind just said. The switch knows what MAC's are attached to its ports. If you were to disconnect your switch from the rest of the network, you could still communicate between the two systems just fine. The traffic never goes past the first switch unless its bound for a MAC address it doesn't recognize! The only time the traffic would reach the router is if its bound for a MAC that isn't recognized on the current subnet, at which time it heads for the gateway of last resort, or another network, if the router allows it.
 
No, if the switch is a layer 2 switch, and the subnets of the computers on that switch differ, the switch is not intelligent enough to route traffice to computers with different IP subnets. Therefore, it has to ask the router where these computers belong and then forward the information to the appopriate MAC address.

Layer 3 switches are able to route at the IP level and are able to see different IP subnets and can route without the help of a router.
 
Correct, but his machines are on the same subnet.

I went back and reread your post and understand what you are saying now. That last sentence really threw me for a loop until I put the emphasis on it correctly. I think grammatically there shouldn't be a period before your last sentence, as the "unless" continues on from the previous sentence.

We are saying the same thing.
 
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