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Beg VLAN /sw question...

Unanswered Question
Oct 26th, 2007
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This is what I am trying to do:

Switch 1 ----> Crossover ----> Switch 2

Switch 1 has an IP of say

I put Port 10 into VLAN 60 and connect it w/crossover to port 10 of Sw2.

For switch 2 I give it an IP of

I put port 10 into VLAN 60 and connect it w/crossover to port 10 of Sw1.

I know that Sw1 and Sw2 are not in the same subnet.

Since they are in the same VLAN shouldnt I be able to ping each other?

I obviously can not and the SW2 led is amber. SW1 led is green.

Thank you.

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uubozou11 Fri, 10/26/2007 - 15:19
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Oh yeah, I have verified that they are in the VL database also.

uubozou11 Fri, 10/26/2007 - 15:27
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To add...they already are a part of a diff admin VLAN and both are 2924s.

Kevin Dorrell Fri, 10/26/2007 - 19:28
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  • Green, 3000 points or more

Just for information, when you gave the switches their IP addresses, you did so on a VLAN 60 interface? What mask did you use?

But that does not really matter. What does matter is that they are on different subnets. Therefore, normally they would want to communicate through a router. Did you have an ip default-gateway configured on either switch?

Now, if you take a router with ip routing disabled, and you configure no ip default-gateway, then it will ARP for everything, even stuff off its own subnet. So I think two routers configured in that way would talk to each other OK, but I have not tested it.

What is interesting in your case is the amber LED. Since the situation is symetrical, why should the two sides be showing different LEDs? That normally means that SW2 has errdisabled its port. Have a look at show int on SW2.

Also, do you have spanning-tree portfast on both sides? If not, do not judge whether it is working until you have waited at least 30 seconds for the Spanning-Tree to put the port in forwarding.

Kevin Dorrell


uubozou11 Sun, 10/28/2007 - 09:54
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I will check the spanning tree portfast Monday when I get in. These are production switches and items on other ports work, but just can not the switches to talk to each other...but knowing my greeness here, I know its going to be something simple, I hope :)

uubozou11 Mon, 10/29/2007 - 09:04
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The port is not in err disabled status, the sh int looks likes nothing is connected (down/down). I do not have spanning-tree portfast on any of the respective ports in question. I tried a new cable this moring, no good, one side of sw is green (up/up) the other switch the cable is plugged into is amber (down/down).

Hi, you need routing to ping between subnets, are your switches miltilayer? if so you should check your RSM config, if not check the default gateway on your switch with the amber light. You are correct they are on the same vlan but not in the same subnet, you could try changing the ip to the same subnet as a test, it could answer some question for you about the config.


joshproano Sun, 11/04/2007 - 19:30
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In regards to SW2 and its amber port LED.. Here are a few things to check.

1. Verify VLAN60 exists in the VLAN databse. "sh vlan" should show VLAN60 in the table.

2. Verify there is no spanning-tree bpdu-guard on the uplink port.

3. Check your crossover cable pinouts.

In regards to your question of layer 3 traffic.. assuming you can get a link up between the two switches... and assuming your using somewhere between /8 through /30 subnetting, the answer is not without a router. Even though they are sitting in the same vlan (Layer2) they are different networks (Layer 3).

For the routing piece if you had lets say...



ip routing

vlan 60

name Test

int vlan 60

ip address

ip address secondary


vlan 60

name Test

int vlan 60

ip address

ip default-gateway

pings would be possible between 10Net and the 192Net

There are other ways to do this and other potential answers to the ping question. But in the example traffic would be able to cross network boundaries.

uubozou11 Tue, 11/06/2007 - 15:53
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Documentation told me I was at one site, when in reality I was configuring a switch at a totally different site. Sigh....


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