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 Strange switch behavior with VPLS connection		  New Topic  Reply to Topic
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anthony
Moderator

USA
2373 Posts
Status: offline
Posted - 01/12/2012 :  10:55:22 AM  Show Profile  Reply with Quote
We have a strange situation. We recently got a new VPLS connection between our two remote offices. Trouble is, when we plug in the connection to our LAN it makes devices that are plugged into our Cisco switches unable to route traffic anymore. They don't "lose" their connection (the link light stays on, and XP still sees the connection as live). They just cannot communicate with anything anymore.

Like I said, we quickly noticed that it was all devices plugged into our Cisco switches (we have 3).

We removed/replaced one from the network to do some testing, and there is definitely something with the Cisco switches.

If we plug a PC into a cheap SMC switch that has our VPLS link on it. We can ping our remote office without an issue.

From PC --> SMC switch --> VPLS --> Remote Office (Ping Good)

However...

From PC --> Cisco switch --> SMC switch --> VPLS --> Remote Office (Ping FAIL)

In that 2nd scenario above, we cannot ping ANY hosts connected to the SMC switch, not just the remote office. (with VPLS in the SMC switch)

However...

If we plug the VPLS into the Cisco switch in that scenario, we can still ping hosts on the SMC, but not the VPLS, or the remote office.

Our config to that cisco switch is below. We don't really see anything that should cause this, but wondered if somebody more versed in Cisco could gaze on it and see if there is.


quote:

3550-SV#show config
Using 1720 out of 393216 bytes
!
version 12.1
no service single-slot-reload-enable
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname 3550-SV
!
enable secret 5 $1$NYvv$J.Yvpdki4G3kvoG2/Yi1g0
enable password ########
!
ip subnet-zero
!
!
spanning-tree extend system-id
!
!
interface FastEthernet0/1
no ip address
!
interface FastEthernet0/2
no ip address
!
interface FastEthernet0/3
no ip address
!
interface FastEthernet0/4
no ip address
!
interface FastEthernet0/5
no ip address
!
interface FastEthernet0/6
no ip address
!
interface FastEthernet0/7
no ip address
!
interface FastEthernet0/8
no ip address
!
interface FastEthernet0/9
no ip address
!
interface FastEthernet0/10
no ip address
!
interface FastEthernet0/11
no ip address
!
interface FastEthernet0/12
no ip address
!
interface FastEthernet0/13
no ip address
!
interface FastEthernet0/14
no ip address
!
interface FastEthernet0/15
no ip address
!
interface FastEthernet0/16
no ip address
!
interface FastEthernet0/17
no ip address
!
interface FastEthernet0/18
no ip address
!
interface FastEthernet0/19
no ip address
!
interface FastEthernet0/20
no ip address
!
interface FastEthernet0/21
no ip address
!
interface FastEthernet0/22
no ip address
!
interface FastEthernet0/23
no ip address
!
interface FastEthernet0/24
no ip address
!
interface GigabitEthernet0/1
no ip address
!
interface GigabitEthernet0/2
no ip address
!
interface Vlan1
ip address 10.0.1.26 255.255.0.0
!
ip classless
ip http server
!
!
snmp-server engineID local 800000090300000C301CB881
snmp-server community public RO
!
line con 0
line vty 0 4
password ############
login
line vty 5 15
password ############
login
!
end

3550-SV#
anthony

There should be only one World's Greatest Dad shirt. And you should have to kill the previous owner to wear it.

anthony
Moderator

USA
2373 Posts
Status: offline
Posted - 01/12/2012 :  4:42:01 PM  Show Profile  Reply with Quote
So nothing huh? Well we decided that since these are 10/100 switches that it's a great time to switch to gigabit. So we ordered replacement ProCurves today.

I'm 99% that nothing in that config would cause that, so it must just be something happening behind the scenes deep down. That's all I can figure at this point...
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wobble_wobble
Honorable But Hopeless Addict

Ireland
4516 Posts
Status: offline
Posted - 01/12/2012 :  8:03:38 PM  Show Profile  Visit wobble_wobble's Homepage  Look at the Skype address for wobble_wobble  Reply with Quote
I've seen this a few times in my old job.

Once you put a managed switch onto it, you get mad outcomes.

STP fixed it once - http://www.cisco.com/en/US/tech/tk389/tk621/technologies_configuration_example09186a008009467c.shtml

Putting bog standard (SMC/ zyxel) switches on either end between the Cisco solved it another time.
Third time the provider had to change the connection.

I bet you can see pings inbound but can't reply, when using wireshark?

Is this a layer 2 or a layer 3 network connection? Using WiMax by any chance?
Joe

After everything that has happened during the month of Jan 07, I do believe that pigs fly backwards!

http://whatismyv6.com/
Edited by - wobble_wobble on 01/12/2012 8:04:36 PM
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