Troubleshooting guide

5-7
ATM and Layer 3 Switch Router Troubleshooting Guide
OL-1969-02
Chapter 5 Troubleshooting Switch Router ATM Interface Connections
Performing OAM Loopback Tests
Note These OAM configuration commands are not stored in the nonvolatile random-access memory
(NVRAM).
If OAM operation is disabled, outgoing OAM cells are not generated, and all incoming OAM cells are
discarded.
To support various OAM operations, the ATM switch router hardware provides OAM cell routing
functions on a per-connection basis for each direction and for different OAM cell spans (segment and
end-to-end). The hardware OAM cell routing determines the destination of an OAM cell received from
the link or the network and then determines whether OAM cells are processed by the ATM switch router
software.
The hardware can perform the following functions on OAM cells:
• Intercept—Intercepted to the route processor queue and processed by the ATM switch router
software
• Relay—Relayed along user cells by hardware without any software processing
• Discard—Discarded by hardware
An ATM connection consists of a group of network points, which are the edges of each ATM switch
router or end system.
Each point can be one of the following:
• Connection endpoint—The end of a connection where the user ATM cells are terminated
• Segment endpoint—The end of a connection segment
• Connecting point—The middle point of a connection segment