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Chapter 5
Troubleshooting the Uplink Cards
Loopback Testing
The POS uplink card supports two loopback modes for network testing, fault isolation, and agency
compliance. The uplink card loopback modes are:
Internal loopback mode—Packets sent from the Cisco 10720 Internet Router out of the uplink card POS
port TX optics are also looped back into the Cisco 10720 Internet Router.
Line loopback mode—Packets received by the POS uplink card port RX optics and sent into the
Cisco 10720 Internet Router are also looped back out of the uplink card port TX optics.
Loopback testing is enabled through software. See the
Cisco 10720 Internet
Additional Troubleshooting Resources
For more troubleshooting information for the uplink card, refer to the following publications:
•
•
Cleaning the Fiber-Optic Connections
For information about cleaning fiber-optic cable connectors and receptacles, see the
Cleaning Procedures for Fiber-Optic Connections
procedures and equipment required to properly clean fiber-optic connections.
78-13113-06 B0
Router.
Chapter 4,
"Troubleshooting", in the Cisco 10720 Internet Router Installation and Configuration
Guide
Cisco IOS Software Configuration for the Cisco 10720 Internet Router
Additional Troubleshooting Resources
Cisco IOS Software Configuration for the
document. It provides detailed illustrations and photos of
document
Inspection and
Book Title
5-17
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Table of Contents
Troubleshooting
