Cat 3750 G question

Answered Question
Mar 8th, 2010

Hello Pros-

We have recently taken on a 3rd party service to monitor our Cisco infrastructure. On Friday 3 alerts were generated related to switches in one of our stacks Not Responding/Device Down -- I'm not sure if they meant ports or the switch itself. My issue is with the below response from one of my team members regarding these alerts:

"...these were on individual ports going down and up. This could be a result of someone disconnecting a laptop from a conference room, Service Desk resetting a phone, Help Desk moving a phone/computer, etc."

Is that statment valid? Does a port on a switch go down when you connect a device to the other end? I find it hard to believe that a NOC would be monitoring for these events if such routine activities can trigger these alerts. I'm grateful for any clarification which can be provided as I obviously have much to learn.

Thanks,

Kelly

I have this problem too.
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Correct Answer by Jon Marshall about 6 years 9 months ago

Kelly

A port will go from up to  down if a device that was connected to the switch is disconnected and it will go from down to up if a device is connected to it. So it could well be a user in a conference room for example attaching a laptop and then taking it with them when their meeting was finished.

Jon

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francisco_1 Mon, 03/08/2010 - 09:05

Under certain circumstances, interoperability issues between Cisco switches and various NICs can result in continuous or intermittent link up/down situations. These link up/down situations are usually a result of power management features or jitter tolerance issues associated with the NIC.

  • For link up/down situations for CatOS, these messages appear and are normal for link up/down situations:

    PAGP-5-PORTTOSPT: Port [dec]/[dec] joined bridge port [dec]/[chars]
    PAGP-5-PORTFROMSPT: Port [dec]/[dec] left bridge port [dec]/[chars]

    This is an example:

    %PAGP-5-PORTFROMSTP:Port 3/3 left bridge port 3/3
    %PAGP-5-PORTTOSTP:Port 3/3 joined bridge port 3/3
  • For Cisco IOS Software-based switches, these messages appear for link up/down situations:

    %LINK-3-UPDOWN: Interface interface, changed state to up 
    %LINK-3-UPDOWN: Interface interface, changed state to down

    This is an example:

    %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to up 
    %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to down

In order to resolve these issues, troubleshoot with these techniques:

  • Disable Windows 2000 and Windows Millennium Edition (ME) power management functions.

    Windows 2000 and Windows ME employ a power management capability that can disable the NIC. When the NIC is disabled for power management, it drops the link to the switch. If there is a concern about the link going up/down on NICs with the Windows 2000 or Windows ME operating systems, disable the power management feature as a first step in order to troubleshoot link up/down situations.

  • Disable the NIC power management functionality. Many NICs support their own power management capability.

    When you troubleshoot link up/down issues, disable this feature. For information on how to disable power management, refer to the NIC documentation.

  • Adjust switch jitter tolerance.

    Hope that helps

see this http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00800a7af0.shtml#maintain

Correct Answer
Jon Marshall Mon, 03/08/2010 - 09:08

Kelly

A port will go from up to  down if a device that was connected to the switch is disconnected and it will go from down to up if a device is connected to it. So it could well be a user in a conference room for example attaching a laptop and then taking it with them when their meeting was finished.

Jon

Reza Sharifi Mon, 03/08/2010 - 09:13

Googi1974 wrote:

Hello Pros-

We have recently taken on a 3rd party service to monitor our Cisco infrastructure. On Friday 3 alerts were generated related to switches in one of our stacks Not Responding/Device Down -- I'm not sure if they meant ports or the switch itself. My issue is with the below response from one of my team members regarding these alerts:

"...these were on individual ports going down and up. This could be a result of someone disconnecting a laptop from a conference room, Service Desk resetting a phone, Help Desk moving a phone/computer, etc."

Is that statment valid? Does a port on a switch go down when you connect a device to the other end? I find it hard to believe that a NOC would be monitoring for these events if such routine activities can trigger these alerts. I'm grateful for any clarification which can be provided as I obviously have much to learn.

Thanks,

Kelly


Hi Kelly,

I agree with you.  Usually the a NOC will not monitor end user devices i.e. PCs, phones, etc... if not they will be looking at a lots of ups and downs. Can you imagine at 8:00 AM when every one is coming in or at 5:00 PM when every one is leaving...

HTH

Reza

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