Solved

2 NICs, 2 subnets, 2 paths: can I do this?

Posted on 2004-08-09
5
295 Views
Last Modified: 2010-04-11
I have two machines, each with 2 NICs, connected to the same two subnets (192.168.1. & 192.168.2.). I was thinking of setting up my host tables like this:

On machineA:
192.168.1.11 machineA
192.168.1.12 machineB   # machineA looks for machineB on subnet 1

On machineB:
192.168.2.11 machineA
192.168.1.12 machineB   # machineB looks for machineA on subnet 2

to spread the traffic between these machines over the two subnets.  Am I setting myself up for trouble doing this?  Will it work?

I doubt it matters, but I'm running Linux (FC1).
0
Comment
Question by:jwolter
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
5 Comments
 
LVL 27

Expert Comment

by:pseudocyber
ID: 11756619
I don't think this will work - you want traffic to travel in a circle?!?!?  

You might be able to get funky with host files, but if A initiates a conversation to B over subnet1, B will learn A's physical address and rember it (ARP cache) and use it to repy to A over subnet1, not subnet 2.

Are these machines only going to talk to each other?  So you won't have any default gateway?  Or would you put it on one subnet on one and vice versa?

I assume you're doing this as a learning experiment - if you're trying to load balance your connections and improve throughput, it won't work.
0
 
LVL 3

Expert Comment

by:fatlad
ID: 11756811
You maybe able to configure some sort of FastEtherChannel link, whereby they will share a virtual MAC and then load balance traffic, never seen it done back to back and it is not possible with two different subnets!
0
 
LVL 4

Assisted Solution

by:Kooroo
Kooroo earned 25 total points
ID: 11756815
Do you mean:

On machineA:
192.168.2.11 machineA <----I changed this line
192.168.1.12 machineB   # machineA looks for machineB on subnet 1

On machineB:
192.168.2.11 machineA
192.168.1.12 machineB   # machineB looks for machineA on subnet 2

I'm not sure what you're trying to accomplish here, but it looks to me like you want to reduce the load on the switches?

It looks to me like you're trying for:
Machine A makes requests to Machine B via 192.168.1 subnet
Machine B makes requests to Machine A via the 192.168.2 subnet

Of course, this is done after a name resolution, so lower level apps which don't use hostnames would use the routing table instead.

You might have to tweak your routing tables, but it should work. The problem is, there's really no point to it beyond you having an overloaded switch. And, let's face it, if 2 workstations are generating too much traffic for your swtich, it's time to buy a new switch.
0
 
LVL 11

Accepted Solution

by:
PennGwyn earned 25 total points
ID: 11768982
> It looks to me like you're trying for:
> Machine A makes requests to Machine B via 192.168.1 subnet
> Machine B makes requests to Machine A via the 192.168.2 subnet

That's it exactly.  And responses will go back over the same leg as the original request.  In effect, he's got a full channel for connections initiated by A, and one for connections initiated by B.

It's crude, but it will work just fine.  Each NIC will have its own MAC address, so neither machine will "know" that both the partners it's talking to are the same machine.
0
 
LVL 1

Author Comment

by:jwolter
ID: 11813172
Since people were wondering what I'm trying to do here, I've actually got a whole cluster of machines, and I happen to have two switches and two NIC's on each machine.  So I thought it might be a cheap way to spread some of the load out.  Thanks for the comments everyone.

John
0

Featured Post

Connect further...control easier

With the ATEN CE624, you can now enjoy a high-quality visual experience powered by HDBaseT technology and the convenience of a single Cat6 cable to transmit uncompressed video with zero latency and multi-streaming for dual-view applications where remote access is required.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Telepresence on backup 3 58
Can’t disable NAT protocol in Windows Server 2012 3 87
Alot of sessions on a PC is generated 3 85
Certifications 8 40
Short answer to this question: there is no effective WiFi manager in iOS devices as seen in Windows WiFi or Macbook OSx WiFi management, but this article will try and provide some amicable solutions to better suite your needs.
Let’s list some of the technologies that enable smooth teleworking. 
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're looking for how to monitor bandwidth using netflow or packet s…

733 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question