Hardware Bypass And Link Changes And Drops; Troubleshooting Loose Connections - Cisco IPS-4255-K9 - Intrusion Protection Sys 4255 Installation Manual

Troubleshooting the Appliance

Hardware Bypass and Link Changes and Drops

Hardware bypass is available on the 4GE bypass interface card, which is supported on IPS 4260 and
Note
IPS 4270-20.
Properly configuring and deploying hardware bypass protects against complete link failure if the IPS
appliance experiences a power loss, critical hardware failure, or is rebooted; however, a link status
change still occurs when hardware bypass engages (and again when it disengages).
During engagement, the interface card disconnects both physical connections from itself and bridges
them together. The interfaces of the connected devices can then negotiate the link and traffic forwarding
can resume. Once the appliance is back online, hardware bypass disengages and the interface card
interrupts the bypass and reconnects the links back to itself. The interface card then negotiates both links
and traffic resumes.
There is no built-in way to completely avoid link status changes and drops. However, you can greatly
reduce the interruption time (in some cases to sub-second times) by doing the following:
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For More Information
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Troubleshooting Loose Connections

Perform the following actions to troubleshoot loose connections on a sensor:
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Cisco Intrusion Prevention System Appliance and Module Installation Guide for IPS 7.0
A-24
Make sure you use CAT 5e/6-certified cabling for all connections.
Make sure the interfaces of the connected devices are configured to match the interfaces of the
appliance for speed/duplex negotiation (auto/auto).
Enable portfast on connected switchports to reduce spanning-tree forwarding delays.
For more information on hardware bypass and the IPS 4260, see
For more information on hardware bypass and the IPS 4270-20, see
Make sure all power cords are securely connected.
Make sure all cables are properly aligned and securely connected for all external and internal
components.
Remove and check all data and power cables for damage. Make sure no cables have bent pins or
damaged connectors.
Make sure each device is properly seated.
If a device has latches, make sure they are completely closed and locked.
Check any interlock or interconnect indicators that indicate a component is not connected properly.
If problems continue, remove and reinstall each device, checking the connectors and sockets for bent
pins or other damage.
Chapter A Troubleshooting
Hardware Bypass, page 3-4.
Hardware Bypass, page
OL-18504-01
4-5.