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| Thread ID: 24953 | 2002-09-22 09:49:00 | Network router/hub problem | tbacon_nz (865) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 82111 | 2002-09-25 01:35:00 | If it's a switch (and therefore isolates the hosts from each other) ethereal will see only what is going on with the host it's running on. But you can set it up on a machine which is used very little (for preference)and just wait until the problem happens. (You can probably select what sorts of logging etehreal does --- start with SNMP --- but remember to clear the log file from time to time. Log files can quickly fill a disk if you don't keep an eye on them.) If you can then see what traffic goes between that machine and the "device" in the storm mode, you can probably discover exactly what is going on. I assume you have less polite names for the "device" by now. ;-) |
Graham L (2) | ||
| 82112 | 2002-09-25 02:49:00 | I'll probably go quiet for a while now, while I try to figure out ethereal and then wait for something to happen. Last questions then, (for now anyway ): What actually is the difference between a hub, a switch and a router? - please correct/fill in the gaps below: A hub provides interchange/connection between machines on a single network... A switch does the same but isolates the hosts... (why?) A router does the same plus connects between two or more networks... An what's the diff between managed and unmanaged, and why would I want one or the other? Thanks everyone for your help. :D |
tbacon_nz (865) | ||
| 82113 | 2002-09-25 03:06:00 | A hub ... correct. It's like a telephone party line. A switch: it isolates the different hosts (or rather the connections) so that, say, box1 can talk to box3 andbox 2 can talk to box5 at the same time, at full speed. In a hub, you get "collisions" if box1 and box 2 send packets at the same time. That means that both have to resend their packets (after random delays). The 10 Mbps bandwidth is shared in a hub between all the active "connections". In a switch each connection has the full bandwidth available. A switch is like a PABX without any outside lines. A router connects networks. It take no action if packets are beween hosts on the same network. If it recognises an IP address as being foreign, it will use its other port to "route" it elsewhere. It might have to ask where "elsewhere" is, and when it finds out, it stores that information. A router is quite a powerful computer, running clever software. Some routers include a hub in the same box... usually ADSL units which contain the line interface (modem) router, and a hub ... but the router is a separate functional unit, which does a complicated task. A router+hub is like a PABX with outside lines, and way of accessing a world-wide directory service, which can discover the paths to remote networks. |
Graham L (2) | ||
| 82114 | 2002-09-25 03:47:00 | Sorry to flog this to death, but... So a switch is probably more than I would need for a 3-4 PC peer-to-peer network that is _very_ lightly loaded apart from when doing backups? Just looking at an online catalogue and I see references to a "switched hub" - is that some sort of hybrid, or is it marketing speak for a hub (or a switch!)? And managed/unmanaged? Ta everso, |
tbacon_nz (865) | ||
| 82115 | 2002-09-25 04:01:00 | From experience, I can say a hub is adequate for such a network. Even doing backups, you are unlikely to have traffic on any but the host and client at the time. Mine is also only running at 10 Mb. Its possible the "switched hub" you refer to is a hub with auto speed switching, 10/100Mb. That wouldnt necessarily make it a switch, just a speed sensing hub? On the other hand it sould be a badly described switch. Simply, you can tell by the price, there is no such thing as a free lunch. If you can afford a switch then OK. You dont really need one though. I run 4 pcs, printer and adsl router on a hub and its fine. Its a lightly loaded network, probably just like yours. It takes a while to copy over a full HDD sure, but I back up locally to a second HDD more often. |
godfather (25) | ||
| 82116 | 2002-09-25 04:02:00 | Yep: switched hub = switch . It's more important if you have a heavily loaded system, but becoming the standard . Managed: some (expensive) hubs have management . . . that means that you can (on big networks, usually) get the hub/switch to send information to a monitoring programme run by the system administrator, so she can see slowing down, keep track of who's doing what, get error messages . . . It also allows remote control of the device, even locking out ports so no-one can add an extra computer "illegally", etc . You don't need it . Thinking about it, since you have collisions, you've almost certainly got a plain hub . With a system that size, you'd probably get a small switch for a reasonable price . Rather than tracing the "problem" it's probably easiest to unplug it and put in a new one . Have a look at pricespy (http://www . pricespy . co . nz/) . A quick look (search on "switch") gave the cheapest at $67-50 . "hub" didn't have any . . . maybe they're obsolete . ;-) |
Graham L (2) | ||
| 82117 | 2002-09-25 04:21:00 | Thanks again everyone for all your help. I suspect just replacing the box is the best option, but I think I will still have a go at ethereal, just for my own education. And I finally understand the difference between all the the terms! :D |
tbacon_nz (865) | ||
| 82118 | 2002-09-25 07:24:00 | Running Ethereal is rather easy. You will want to set it up in promiscuous mode (so it will log ALL network traffic on a hub) and it is often best to have it running Update list of packets in real time with automatic scrolling in live capture. I was just looking at the ethereal site and I'm not to sure that it will be that easy to compile it on a Windows machine. Before downloading check out the requirements and see if your machine already has the additional packages. If not, it would be best to see whether these itema are easy to obtain. There seem to be a number of other programs available for windows that may be easier to install. |
Gorela (901) | ||
| 82119 | 2002-09-25 08:53:00 | There is a binary available of ethereal, so I downloaded and installed that, plus another dll WinPcap which it said it needed. Most of the options/help etc were Greek to me, so I will have to rely on 30+ years of IT experience to help me make intelligent guesses about what to do. Of course now I have the tool, the hub will never misbehave again! |
tbacon_nz (865) | ||
| 82120 | 2002-09-26 03:42:00 | Well, if you've dealt with the "standard" RS232 for terminals, Ethernet and TCP/IP will be a doddle for you. If you've used a Decserver, that's an example of something like a managed hub. | Graham L (2) | ||
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