Cisco IPS-4255-K9 Installation Guide - Page 302

Troubleshooting the Appliance Chapter A Troubleshooting Hardware Bypass and Link Changes and Drops Note Hardware bypass is available on the 4GE bypass interface card, which is supported on IPS 4260 and 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: • 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 • For more information on hardware bypass and the IPS 4260, see Hardware Bypass, page 3-4. • For more information on hardware bypass and the IPS 4270-20, see Hardware Bypass, page 4-5. Troubleshooting Loose Connections Perform the following actions to troubleshoot loose connections on a sensor: • 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. A-24 Cisco Intrusion Prevention System Appliance and Module Installation Guide for IPS 7.0 OL-18504-01