Vonage/PAP2/Switch problems

Not so much a problem as a curiosity. I'm hoping someone has seen this before and knows why it happens.

At the office we've got a 7 MBit connection coming in from Nexweb. The incoming connection goes to a 10/100 switch (let's call it switch 1). One port of switch 1 goes to a WiFi router which also provides DHCP service for devices connecting to it wirelessly devices connecting through the rear-panel ethernet switch ports. One of the ethernet ports on the back of the WiFi router goes to another 10/100 switch (let's call this one switch


If the PAP2 is connected to a port on switch 1 all works as expected. If I plug it into a port on switch 2 the ethernet light never lights and the power light keeps flashing in it's one-two pattern that says it's rebooting (or acquiring a signal or whatever the heck it's doing). If I plug it into one of the ethernet ports on the back of the WiFi router, it functions normally.

So the summary is: plugged into a switch one hop from our net connection: works. Plugged into WiFi router two hops away: works. Plugged into switch three hops out: doesn't work.

The solution for now is obvious: plug into switch 1. But I'd like to understand *shy* it doesn't work when plugged into switch 2.

And ideas?

Reply to
Dan M
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Firstly, if you are really using a true "switch", then there is no "hop". Or more precisely, a "switch" will not increase the "metric".

A "hub", on the other hand, DOES increase the "metric", and could lead to the problem you describe.

The other thing to check is the specifications on your "switch #2", and double check the cables you are using. Some siwtches, like the Linksys SD2008, are very advanced and do not care what kind of cables are used. Switches like the SD2008 will automatically adjust operations to compensate for "straight through" and "cross-over" cables. This is very useful because you just use what you have, plug and play - no problem. But older switches usually require that straight through cables are used. Cross-over cables should only be used for things like uplinking to other equipment.

So check your specs and your cables. Make sure that everything is connected properly. Your switch #2 should be connected to the wifi router through the uplink port. If not, you may have to use a cross-over cable and one of the regular ports. Some routers and switches actually had a physical switch on them to change the crossover function. You may have to change the position of the function switch (I had one of these pesky things on a hub once - pain in the neck). If there is an "uplink" port, then use of it usually precludes the use of one of the other ports (often port 1).

Download the manuals, read'em, and check those cables. This is my bet.

Personally, I think the PAP2 is a piece of junk. This was the first VOIP interface that my provider sent to me. It did not work properly AT ALL. It constantly screwed up, and had to be reset. To the point that I had to reset it before I made a call. I had two lines on it. You are supposed to be able to use them both simultaneously, but with the one I had - NO WAY. If one line was in use, the other would not call out or permit a call in. Even then, after calling on one line, you had to unplug the power to reset before you could make a call on the other line! That damn PAP2 almost cost my provider my business!

And I tried EVERYTHING. I am also a network sysadmin, so I know my plumbing. lol. I finally got a switch, and activated a second IP form my ISP - just to show my provider that is was NOT my hardware.

I insisted on getting a different box - so they gave me an RT31P2-NA. This box works just fine. I have noted that sometimes my service does not work as expected. What they told me is that they change config files from time to time, and that sometimes it takes a while for the VOIP box to reload the information. I can - and do - force the situation by powering down the box, letting it sit for 5 min, and then powering up again. I now do this every couple of days, and I have had NO problems with the service since.

VOIP has a LONG way to go, but it still saves me money. :)


Reply to

I'm pretty sure that the cables are all appropriate. I've got a couple dozen PCs also plugged in to switch #2 and they all work fine.

I realize that using switches won't actually increase the real hop count

- that was just my clumsy attempt to quantify how many active devices we were connecting through :)

So the mystery is, PCs connected to switch #2 operate great, but the PAP2 connected to the same switch doesn't. It doesn't even activate the link LED on the front panel. I guess that will remain a mystery for a while.

Thanks for the response!


Reply to
Dan M

What happens if you plug switch 2 into the internet, and plig the PAP2 into switch 2???

You may want to get your voip provider to configure your PAP2 with a static address for your LAN. Then you can enable that address for the DMZ. This might help.

Let us know how it goes.

Reply to

Sounds like you've got things in a bit of a rats nest. Why are you daisy chaining switches this way? Why aren't the Wifi router and "Switch 2" both connected to the incoming 10/100 switch? No sense in layering things more than is necessary.

How many devices do you have on this network? Most low-end Wifi routers are really not up to handling more than a dozen lightly-used computers. Their onboard packet handling really can't keep up. No, it's not merely about having the ports, it's about having enough CPU in the devices to properly handle the load.

So why not leave it there? It's potentially a high-bandwidth device. There's little sense in putting it further 'downstream' from the actual internet connection. You just overload the other switches passing along traffic that doesn't really need to go through them.

Sounds like it's a cabling issue. Probably straight-through versus cross-over.

Flatten the network and don't chain devices any more than necessary. It's probably better to have more ports on the immediate connection, switch 1, and then into that. Instead of into switch 1, then into the wifi router and then to another. Ethernet does have restrictions on how many packet hops are tolerated within a subnet. That may be at issue here but it's more likely a load issue.

-Bill Kearney

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