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HP V1910 switch cannot talk to DSL modem (*FIXED! See OP!*)

MichaelD

MichaelD

Lifer
FIXED AS OF 11 OCT

You know how when someone says "This doesn't work...I've tried everything to fix it" and you say "Well, you haven't tried EVERYTHING, else it would be fixed"? Yeah so:

The fix action had nothing to do with the modem; it was all in the switch, literally.

This is a pretty granular switch. There are settings for MDI, Duplexing and Speed for each port. Guess what I hadn't tried yet? I set MDI and Duplexing to Auto and I set the Speed for Port 1, which is what goes to the modem, to 100 Auto, clicked save and *boom* instant blinky lights. ^_^

It was a matter of trial and error (mostly error) to see what combination of settings worked. Funny how it's typically the easiest thing you overlook...hey at least I tried a different patch cable as my first fix action.

I'm posting through my fine new switch as we speak (type). Now to configure LACP for my editing box (Intel dual copper gigabit PCI-E card). Standby for my next post on "What am I doing wrong with LACP?" LOL! Thanks again for the help. :thumbsup:



____________________________________________________________
I have AT&T Uverse at home and a 3Wire-brand DSL modem/switch. The modem does DHCP for my whole network. My house is hard wired for gigabit ethernet.

Up until now my configuration has physically looked like this:

Modem---cheapo GigE switch next to modem to consolidate hard wired wall plates from house---CAT5E thru house to my office/wall plate---cheapo GigE switch---any number of devices plugged in

I had 4 diff PCs and a printer plugged into the cheapo switch and they talked and grabbed IPs from the modem just fine. Not a single issue.

I bought a (NIB) HP 1910-16G Switch (JE005A) (rebranded 3Com 2920 SFP-Plus) It is a Layer 2 switch and while a lot of it's operation is above my head, I do know enough to normally navigate issues like this. Here's the link to the spec page.

http://h17007.www1.hp.com/us/en/products/switches/HP_1910_Switch_Series/index.aspx#JE005A

Using my "diagram" above for reference, I simply replaced the cheapo GigE switch in my office with the HP and plugged everything into it. NOTHING else in my network/house has changed. Used the same straight Cat5e patch cable to connect the new switch to my wall plate. None of my PCs can grab an IP, I can't surf the net and there is NO LINK LIGHT on the switch to indicate a physical connection to the modem. OK, fine, the modem and switch aren't talking. Here's what I have tried and nothing works.

Tried diff patch cable
Configured static IP for switch on the switch, in same subnet as modem (this works fine for my NAS)
Configured switch to get a DHCP addy from modem.
Configured switch to get a DHCP addy from modem AND set same DHCP reservation for switch in modem. Modem "sees" that the addy is for the switch and even sees it's MAC addy, but NO LINK light on the switch and still doesn't pass traffic (not sure how this is possible)
Tried every single MDI setting on the switch
Tried connecting the modem to diff ports on the switch
Reset switch to factory config (several times) and retried everything above
Tried changing the Duplexing on the modem (Auto/100Full Duplex/half duplex)
Tried just about every combination of the above
/facepalm

The switch's web interface correctly sees all the devices/port speeds plugged into it except the modem.

Can someone point me in the right direction? At this point I'm out of things to try. Thanks very much!
 
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It sounds like you just bought this switch, so have you tried a very basic test (e.g., PC1 and PC2 plugged into switch and communicating) to verify that the switch works properly?
 
I've had the switch awhile...been in the box while I tried to find time to set it up. Since all boxes but my NAS run DHCP off the modem, I haven't been able to test PC-to-PC b/c then I'd have to reconfigure them all w/static IPs. The switch correctly sees "Box A on Port 1" connected at 1000MB and "Printer B on Port 2 at 100MB". Hadn't thought to actually put static IPs on everything and test. I DID use the switch's internal ping command to ping the boxes attached to it and all pings were successful.
 
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theevilsharpie said:
Are the Ethernet interfaces on the 3Wire router set to autonegotiate, or are they explicitly set to a particular link speed?
Click to expand...

Yes, they are (on autonegotiate). Options are: Auto Detect/100BaseTX-Full Duplex/100BaseTX-Auto/same for 10Base. Are you thinking I should try 100Base-Full Duplex?
 
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Just tried all of them with negative results. 🙁 I'll have to re-engage tomorrow with a fresh head; gotta hit the hay. Thank you for your help, theevilsharpie.
 
Any other ideas, folks? I'm at work now, but will be hitting this problem again when I get home later on. This one's really got me puzzled. Even though I've verified that I can ping devices from the switch, tonight I'll hook up two PCs, configure static IPs on them and make sure I can ping each one from the other PC. I'm sure this will be OK though.

Why does a dumb, $25 Layer 1 switch see my modem just fine, but this smart, $300 Layer 2 switch does not? Got to be a setting on the switch vs. a problem with the switch. Rationale is that from the switch's mgmt interface, I can ping all devices attached to it (PCs and printers) but can't ping/see the modem. Thanks much.
 
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First... Layer 2 (your dumb $25) and maybe Layer 2 or 3 ($300 switch) Ie your layers are wrong. Do you mean "managed" vs "unmanaged" etc

Anyway have you tried connecting the DSL modem through the older layer 2 switch? If so do all the led's light up? Have you tried a new patch cable? On the managed switch, you might try disabling or enabling auto crossover (MDI MDI-X) leave speed set to auto. I have seen the 2 wire modems coming with cross over cables in the past (to attach them right to the computer as they are 100BaseT.) If the managed switch has auto MDI-X set to disabled, it may not link up.
 
I don't have a premade xover cable...I can make one tonight and test it out. I figured my trying every single MDI setting on the switch and modem was good enough. 🙁 If the issue was the straight vs. xover cable, why does the dumb device work fine?

What I have NOT tried yet is changing the link speed on on modem (change from Auto to 100FullDuplex) AND changing the MDI setting on the switch at the same time. There may be hope yet.

I'm not an OSI Model guru...but the new switch is most definitely a Managed Device. The older, cheap switch is just a dumb box. No ip, no managent port or web interface, etc I will build a xover cable tonight and give that a shot. Everything works great with the dumb device. Correct link speed, great throughput, etc.

I guess tonight I'll reset the switch to factory configuration (again) and start over. Thanks for the help.
 
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