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Author Topic: How to Check NW Topology?  (Read 3690 times)

jmone

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How to Check NW Topology?
« on: February 02, 2013, 12:59:12 am »

Following on from the thread about Bandwidth Allocation, I added the Dual Port Intel NIC, new main router, new Cable modem but I'm seeing some Odd things:
- Network2.JPG:  Updated Manual Pic of what I "think" the physicall connections looks like
- LAN6.JPG:  This shows what Windows thinks one of the connections are doing and it "looks" right to me and as I would expect
- LAN5.JPG:  This shows what Windows thinks the other connection is doing and as you can see it appears to be doing a round trip through one of my other (secondary) switch. 

I seem to see a drop in download speed over the NW when the second switch is connected which would seem to indicate that extra hops (as shown by Windows) may be real.  Is there any way to see/map what is really happening?

Thanks
Nathan
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InflatableMouse

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Re: How to Check NW Topology?
« Reply #1 on: February 02, 2013, 04:15:10 am »

I need to make sure I understand your situation, so I got a small pile of questions for you :).

- when you say downloading, you mean downloading from the internet or from another one of your pc's/server?
- you're doing the test on the Main PC aka Library Server? Didn't you have 2 pc's with dual NICs?
- this will show from the info I'm asking for below as well, but please explain it in your words: how did you configure the 2nd NICs? Did you team it, does it have an ip in the same subnet range as the other nic, or does it have its own subnet range? Are they hooked up to the same switch? What exactly do you want it to do? I remember the other thread but I'd like to hear you explain it.

I'd also like to see the complete output for 'ipconfig /all', a 'route print' and a 'arp -a' for each pc involved and make it clear which output is from which pc for me please.

Arp -a outputs the list of addresses for each NIC in a pc within broadcast range. This probably wont show your switches as they are unmanaged layer 2 devices, but we'll see what's on there.
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jmone

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Re: How to Check NW Topology?
« Reply #2 on: February 02, 2013, 03:27:18 pm »

I need to make sure I understand your situation, so I got a small pile of questions for you :).

Thanks IM...

- when you say downloading, you mean downloading from the internet or from another one of your pc's/server?  From the INet.  I get 100mbps down 1.6mbps up (from the ISP based Speed Checker) and while I have not able to confrim it my feeling is that I lose around 10% or so when the topology looks more like the complicated one.  Eg this morning both Network Connections look like the more complicated LAN5.JPG
- you're doing the test on the Main PC aka Library Server? Didn't you have 2 pc's with dual NICs?.  I do but I've not physically dont have a second cable plugged into the WHS (my thought was this was it could only ever saturate one link).
- this will show from the info I'm asking for below as well, but please explain it in your words: how did you configure the 2nd NICs?  On the MAIN PC I just plugged them in and tried both the latest INTEL Driver from their Website and that Windows would download (V19.16.10.0 dated 30th Oct 2012).  There are no exposed options to really play with on this Win7 box, only WOL (while on the WHS Box you see a bunch of additionalon options on dedicated Intel Tags in the driver config).
   - Did you team it, does it have an ip in the same subnet range as the other nic, or does it have its own subnet range?  Nothing fancy at all.  They are not teamed (I did try to google this before but could see no way of doing it), so they each have been assigned static IP for the router in the same sub net range as all the other devices in the house.
   - Are they hooked up to the same switch? both runs are to the same switch.

What exactly do you want it to do? I remember the other thread but I'd like to hear you explain it.  The new nic cards seems to be working well as I can now get more that 1gbps from the box (eg the bottle neck as moved to the HDD which is fine).  This means that no one other PC can take all the bandwidth from the box leaving capacity to server a second video stream if needed.  I guess, I'd "like" to have these two links "teamed" rather than two independant links but I just don't know how.  After my upgrade to cable I was having other difficulties when my download from the INet was sometimes being capped at 1.6mbps (NW trafic has always been fine).  As part of solving this issue (it was the ASUS AI Suite II - "Network iControl" causing the issue) I found a bunch of bunch of protcols stuffed on top of the Driver Stack. I've cut it down to:
- Client for Microsoft Networks
- Virual PC Network Filter Driver
- QoS Packet Scheduler
- File and Printer Sharing for Microsoft Networks
- Internet Protocol Version 6 (TCP/IPv6)
- Internet Protocol Version 4 (TCP/IPv4)
- Link-Layer Topology Discovery Mapper I/O Driver
- Link-Layer Topology Discovery Responder
 
and removed:
- Winpk Filter Light Weight Filter
- Realtek Teaming Protocl Driver (NDIS 6.2)
- Realtek Vlan Protocol Driver (NDIS 6.2)
- Realtek NDIS Protocol Driver
- HTC NDIS Protocol Driver
 
- I'd also like to see the complete output for 'ipconfig /all', a 'route print' and a 'arp -a' for each pc involved and make it clear which output is from which pc for me please.  I've attached the reports as run from the MAIN-PC.  I use ipconfig for simple tasks like releasing / renewing IP addrs but that is about it.

Thanks
Nathan  
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jmone

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Re: How to Check NW Topology?
« Reply #3 on: February 02, 2013, 03:38:44 pm »

FYI - Just worked out how to Bridge the two ports in Windows (if that is what teaming is).  The map looks like the complicated on still.... (Got to run for a bit!)
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InflatableMouse

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Re: How to Check NW Topology?
« Reply #4 on: February 02, 2013, 03:45:48 pm »

You can take the file offline if you wish as it contains your public ip and maybe some other sensitive stuff.

I'm going through it now.
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InflatableMouse

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Re: How to Check NW Topology?
« Reply #5 on: February 02, 2013, 04:21:45 pm »

You can't really team those NIC's because your switches can't handle it. What will happen if it even works at all, is that both NIC's will be used for sending data, but only one will be used for receiving. This is because when you team them, they will get 1 IP address but they will each still have their own unique MAC address. When receiving data, the switch being a layer 2 device won't be ip address aware, but will be looking at MAC addresses exclusively. Since the 2 nics will have their own unique MAC address, only one nic will receive because thats the only thing the switch will know. This won't help you at all as sending on 2 lines to a pc that receives with 1 line is ... quite useless :).

First thing you need to do (or remember for future reference) is remove the default gateway from the 2nd nic. A pc can only ever have 1 default gateway. In your case I don't think it will change anything but its a matter of principle - never use more than 1 default gateway. In more complex environments with multiple NIC's connecting to different subnets, this IS a real issue; one NIC gets the default gateway, other traffic that needs special care will get permanent routes. But because you have only one subnet and no other routes than the one onto your only network, it probably didn't cause any trouble.

If I understand you correctly, you're testing download speed from the internet with and without a 2nd switch hooked up. The Windows network maps are confusing because they tend to split a single device up in 2 devices - is that the case in those screenshots as well?

I think BEHome and the first switch above is actually a single device isn't it? I suspect the same from the other BEHome. Please confirm this.
Why is that HUB appearing when you hook up the extra switch?

I think what you need to do now is to make things easier. One NIC, One switch, Internet. Test that a few times and get a baseline of the speeds you're getting. Put it in a spreadsheet or something. About 10 tests would be good with a few minutes pause each time.

As the Windows maps are confusing, and the names do not match your own map, I don't understand what it really looks like. I'm going to asume your own map is correct. THat means the second switch (the left one) is the one you're connecting and disconnecting; correct? That switch has nothing to do with the route from your pc's to the internet. I'd say its virtually impossible for the 2nd switch to add hops to your internet traffic ... UNLESS something really weird and unexpected is happening and your switches are misbehaving; if that's the case that could have been triggered by multiple default gateways and some packets going out on the other nic and the switch not knowing how to handle them, sending them the wrong way. Your pc would have to resend them until they go out over the interface that does have the correct way to the internet, that could cause the drop in speed you're seeing. But this is all very stretched guesswork and very simple to fix if its happening: simply disconnect the 2nd NIC's (unplug network cable), and unplug the switches from power for a few minutes (don't use a power switch as it may put it in standby and not clear its memory). It will rebuild its ARP tables when you plug it back in. Don't plug in the 2nd nic network cables yet.

What I'd do if I were you is reconfigure the 2nd NIC's with a fixed IP in its own subnet. Pick 192.168.2.10 and 192.168.2.11 with a subnet of 255.255.255.0. Do NOT give it a default gateway :). These NIC's will operate internally only and you can give them their own DNS suffix, like .local. You can send your copy jobs or backups to the new ip address or to hostname.local (with the DNS suffix it should resolve to the 2nd internal only ip address). Then reconnect the wires to the switch and the switches will update their ARP tables for these nics.

I'd say in the situation above, its virtually impossible for network traffic to get confused, lost or slowed down somehow. I think this would be the most preferred configuration, its straightforward and dedicated to the tasks you perform.



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jmone

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Re: How to Check NW Topology?
« Reply #6 on: February 02, 2013, 04:49:00 pm »

OK - It may just be how Windows Network Map works (or does not work) and I'm chasing my tail.  

This is as simple as it gets.  I've removed all switches and AP from the network and have the MAIN PC connected directly to the WNDR3800 (combined Switch, AP, Router) with the only other wired connection being to the Cable Modem (not show).... and

- S1C5.JPG : Looks exactly as you would expect
- S1C6.JPG : Has this complicated map but it is exactly the same as above  

Note: after a while both connection will look like S1C6.JPG

The only difference is that how the Wireless Printer connection is treated between the two.  So in reality the two Switches, Hubs, and BEHome (WAP) is all just internal to the WNDR3800 and "appears" when a Wireless device connects.
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InflatableMouse

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Re: How to Check NW Topology?
« Reply #7 on: February 02, 2013, 04:55:18 pm »

I'll have a look in the morning, my bed is calling me  ;).
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jmone

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Re: How to Check NW Topology?
« Reply #8 on: February 02, 2013, 05:04:19 pm »

Thanks mate
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jmone

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Re: How to Check NW Topology?
« Reply #9 on: February 02, 2013, 05:34:57 pm »

I think I worked it out......

Here is a map that makes sence (Final.JPG)

The difference?  I removed the USB Key I had left in the card reader built into the Epson Printer.  All of these extra switches, hubs etc then disappeard from the network map and the connections now look "correct".

Thanks anyway (it was "fun")

Nathan
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InflatableMouse

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Re: How to Check NW Topology?
« Reply #10 on: February 03, 2013, 02:33:49 am »

I suspect that may be why they removed that map functionality from Windows 8 as I can't find it anymore. :).

So no more download speed anomalies?
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jmone

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Re: How to Check NW Topology?
« Reply #11 on: February 03, 2013, 03:57:00 am »

I think it is all fine.....?!?!?  but will wait and see.  I really started chasing my tail when it was capped to 1.5mbps thanks to the Asus Utility as it was the last thing I was looking for.  I then got all bent out of shape with what Windows was reporting as the path between this PC and the WAN.  I guess there is no way it was going via the printers USB hub and it was just windows having a hissy fit about how it was being mapped out.
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