[NTLUG:Discuss] what is the problem?

Tue Jul 30 18:06:34 CDT 2002

This could be a number of issues including line inductance causing the nway negotiation to have some issues negotiating a proper connection resulting in something that could look like massive collisions on that segment.  One way to test this would be to try the two hubs together going from a regular port on switch a to the uplink on switch b using a straight through cable sans the receptacles and see if the link light is steady.

-----Original Message-----
From: discuss-admin at ntlug.org [mailto:discuss-admin at ntlug.org]On Behalf
Of m m
Sent: Tuesday, July 30, 2002 9:34 AM
To: discuss at ntlug.org
Subject: Re: [NTLUG:Discuss] what is the problem?

Thanks for you all.

Here is more detail:
switch A is SMC (8 ports), switch B is Trendware (4 ports).
This time I just try switch A anb B. (leave switch C alone)
Switch A connect to router and other PCs, all works fine.
If I use Switch B connect to router and other PCs, all works fine, too.
the connection diagram:
router
  |
  |        cable A   cable B   cable C
[switch A]---------O---------O---------[X]
                   ^         ^
                   |         wall receptacle
                 inline receptacle

cable A and B is custom made straight-thru cable,  use BLOG color scheme.
cable A connect to switch A regular port:
1. use cable c (straight-thru) connect to [x] (x=PC), works fine. the PC can 
through the internet.
2. use cable c (straight-thru ) connect to [x] (x=switch B, uplink port), 
the light is blinking, indicates collusion.
3. use cable c (straight-thru ) connect to [x] (x=switch B, regular port), 
no lights on switch B is on, it doesn't work.
4. use cable c (crossover) connect to [x] (x=switch B, uplink port), the 
light is on, it seems all connected, but the PC connected to this switch (B) 
cannot go through the internet. PCs connect to this switch talks. but not 
talk to PCs on switch A.
5. use cable c (crossover) connect to [x] (x=switch B, regular port),
no lights on switch B is on, it doesn't work.
I don't think connect switch A (uplink port) to any port of switch B is a 
correct way to do connection. (through I tried, all failed)

thanks.

>From: "Chris J Albertson" <alb at chrisalbertson.com>
>Reply-To: discuss at ntlug.org
>To: <discuss at ntlug.org>
>Subject: Re: [NTLUG:Discuss] what is the problem?
>Date: Mon, 29 Jul 2002 12:12:03 -0400 (EDT)
>
>You've done a lot of the debugging I would have done to this point.
>When connecting switches, it's either regular port to uplink via
>straight-thru cable... or regular port to regular port via cross-over
>cable.
>Since You're doing the regular port on switch A to uplink on B, you have a
>straight-thru. If it works when you just replace switch B with a PC, then
>I'd say switch A and the straight-thru cable work fine.
>Now, if you get the same results with switch C uplink port, I would have
>to say that you've got something wrong with the uplink configuration of
>switches B and C. I doubt switch A has anything to do with this, nor do I
>think it's the cable.
>One thing I would do for sure is remove all devices from all the switches.
>If these are truly switches as you say, then you have some software
>configuration to start looking at. You may have some virtual LAN setups or
>such going on. I dunno.
>Another thing to try is to get switches B and C talking. If you can get
>those switches to connect, then start adding devices to them. You may
>find, as mentioned by someone else, that your cable modem is hurting you.
>
>In my experience with getting switches and hubs to talk on the same
>subnet, bad uplink connections usually identify themselves with no link
>light at all. This is the puzzling part.
>
>Good luck!
>
>Chris
>
>
>Kelledin said:
> > Your cable modem should be connected directly to a router, not
> > sitting on a switch.  Having it sitting on your network like
> > just another networked PC may work, it may not.  Even if it
> > seems to work, it may force certain limitations.  If PCs on
> > Switch A are able to reach PCs on Switch B (and vice versa), but
> > not all of them can use the cable modem, this is likely to be
> > your problem.  Your solution in this case would be to set up a
> > router (preferably Linux on an old 486 with two Ethernet cards).
> >
> > If PCs on Switch A are _not_ able to reach PCs on Switch B, then
> > you need to check a few things:
> >
> > 1) See if disconnecting the cable modem allows the two switches
> > to work properly together.
> > 2) See if the uplink port being used requires a crossover
> > connection (versus the more standard straight-through).  Some
> > 10baseT and Fast Ethernet switches require this; copper Gigabit
> > switches should not.
> > 3) Make sure the uplink port being used is actually set to work
> > as an uplink port.  Most switches have a setting that can force
> > the uplink port to work just like any other port.
> >
> > On Monday 29 July 2002 01:33 pm, m m wrote:
> >> Hi All:
> >>
> >> I have a problem on internet connection, please help.
> >>
> >> switch A connect to cable modem, switch A is about 100-150
> >> feet aparts for PCs and switch B. the connection cable are two
> >> cat5 with inline receptacle. I can connect from network switch
> >> A to any of my PCs, it works. I use the same wire to connect
> >> to network switche A (regular) to Switch B (uplink), it does
> >> not work. the switch A light is on (indicate good), the switch
> >> B uplink light is blinking (indicates collusion) I use the
> >> same wire to connect to network switche A (uplink) to Switch C
> >> (regular), it does not work either. the switch A, the switch B
> >> lights are blinking (indicates collusion)
> >>
> >> any one have a clue?
> >>
> >> thanks.
> >>
> >>
> >> ______________________________________________________________
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> >> _______________________________________________
> >> http://www.ntlug.org/mailman/listinfo/discuss
> >
> > --
> > Kelledin
> > "If a server crashes in a server farm and no one pings it, does
> > it still cost four figures to fix?"
> >
> > _______________________________________________
> > http://www.ntlug.org/mailman/listinfo/discuss
>
>
>
>
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