Traffic Question

Answered Question
Dec 9th, 2009

Hello All:

Sorry if this is off topic but I honesty don't know what other forum to seek out help in. I always get great answers/solutions here.

I have been asked to create a "private network" by dual homing 5 or 6 servers that would use this network to transfer large amounts of data while running processes (sql, sas) across the other connection. I honestly don't know how this can be accomplished. Any ideas?

DJ

I have this problem too.
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Correct Answer by Jon Marshall about 6 years 11 months ago

DJ214 wrote:

Some of it will be script driven so I'm thinking as I'm typing that if you mapped a drive to the server via the private IP address, and the script referred to it with that drive letter, that would take care of that. The only problem that would arise is by call servers by name because they're available on both network.


Am I understanding you with regards to the provate network that it bears no GW, however, the servers are still aware of each other through the connection itsself? Is that correct?

Thanks again. Helps to think out loud here and certainly get other input.

DJ

DJ

There is nothing to stop you having another entry in DNS for the server ie. server-backup . Not sure about WINS, been a while since i looked at Windows specific networking.

Am I understanding you with regards to the provate network that it bears no GW, however, the servers are still aware of each other through the connection itsself? Is that correct?

Yes, that's correct. The servers will be able to communicate with each other on their 2nd NICs because they are in the same subnet. You don't need a gateway because if the servers want to talk to any device not on their local subnet(s) they should use their main production NIC and it's default-gateway.

Jon

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Jon Marshall Wed, 12/09/2009 - 07:01

DJ214 wrote:

Hello All:

Sorry if this is off topic but I honesty don't know what other forum to seek out help in. I always get great answers/solutions here.

I have been asked to create a "private network" by dual homing 5 or 6 servers that would use this network to transfer large amounts of data while running processes (sql, sas) across the other connection. I honestly don't know how this can be accomplished. Any ideas?

DJ

DJ

You need to create a separate vlan for this private network. Do not create a L3 SVI for it because there is no need to route.

You then can either -

1) use an existing switch for the vlan

OR

2) if the servers are moving a lot of data it would be a good idea to buy a separate switch purely for this network. That would keep the traffic off the main production network.

I would recommend option 2) if you have the budget.

Jon

DJ214_2 Wed, 12/09/2009 - 07:12

Thanks Jon - that was my intent but I guess the real question is this. If I have 2 NICs in the server 10.0.1.x and 192.168.1.x. How can I tell the server to transfer certain traffic over the 192 IP and other traffic over the 10x IP.  Am I missing something incredibly simple here or is there more to it.

Thanks

DJ

Jon Marshall Wed, 12/09/2009 - 07:17

DJ214 wrote:

Thanks Jon - that was my intent but I guess the real question is this. If I have 2 NICs in the server 10.0.1.x and 192.168.1.x. How can I tell the server to transfer certain traffic over the 192 IP and other traffic over the 10x IP.  Am I missing something incredibly simple here or is there more to it.

Thanks

DJ

DJ

Normally a server that has 2 NICs and wants to use them both would be an issue because you can only have one default-gateway, so for the other networks you have to add specific routes to the server.

However in your case this is not an issue because it is a private network. So the server will keep it's current IP config including the default-gateway so it can carry on with it's normal job. You add a second NIC and address it. Because the server now has a directly connected interface in that subnet it will now be able to send traffic to other servers in the same subnet. If you then wanted to use that second NIC to send traffic to a different subnet then, as i said above, you would have to add an explicit route to the server but because it is a private network the servers will only use that second NIC to talk to each other within that subnet.

Jon

DJ214_2 Wed, 12/09/2009 - 07:23

Thanks - I omitted this information and I think this is where the problem lies. These servers are available to one another on both NICS.SO if server 1 wants to initiate a data transfer from Server 2, how will that happen. If it's in DNS/WINS as Server1 and Server 2, it's going to reach out to either service to see where to send the data to. Am I making sense?

Jon Marshall Wed, 12/09/2009 - 07:30

DJ214 wrote:

Thanks - I omitted this information and I think this is where the problem lies. These servers are available to one another on both NICS.SO if server 1 wants to initiate a data transfer from Server 2, how will that happen. If it's in DNS/WINS as Server1 and Server 2, it's going to reach out to either service to see where to send the data to. Am I making sense?

DJ

Yes you're making sense

Is there special software to transfer the data  ? I would have thought that you could "tell" the server which other servers to copy the data to.

Jon

DJ214_2 Wed, 12/09/2009 - 07:35

Some of it will be script driven so I'm thinking as I'm typing that if you mapped a drive to the server via the private IP address, and the script referred to it with that drive letter, that would take care of that. The only problem that would arise is by call servers by name because they're available on both network.


Am I understanding you with regards to the provate network that it bears no GW, however, the servers are still aware of each other through the connection itsself? Is that correct?

Thanks again. Helps to think out loud here and certainly get other input.

DJ

Correct Answer
Jon Marshall Wed, 12/09/2009 - 07:38

DJ214 wrote:

Some of it will be script driven so I'm thinking as I'm typing that if you mapped a drive to the server via the private IP address, and the script referred to it with that drive letter, that would take care of that. The only problem that would arise is by call servers by name because they're available on both network.


Am I understanding you with regards to the provate network that it bears no GW, however, the servers are still aware of each other through the connection itsself? Is that correct?

Thanks again. Helps to think out loud here and certainly get other input.

DJ

DJ

There is nothing to stop you having another entry in DNS for the server ie. server-backup . Not sure about WINS, been a while since i looked at Windows specific networking.

Am I understanding you with regards to the provate network that it bears no GW, however, the servers are still aware of each other through the connection itsself? Is that correct?

Yes, that's correct. The servers will be able to communicate with each other on their 2nd NICs because they are in the same subnet. You don't need a gateway because if the servers want to talk to any device not on their local subnet(s) they should use their main production NIC and it's default-gateway.

Jon

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