Troubleshooting guide

5-6
ATM and Layer 3 Switch Router Troubleshooting Guide
OL-1969-02
Chapter 5 Troubleshooting Switch Router ATM Interface Connections
Performing OAM Loopback Tests
If the success rate is less than 100 percent, refer to the “Configuring Interfaces” chapter in the
ATM Switch Router Software Configuration Guide and confirm the interface configuration.
Performing OAM Loopback Tests
OAM performs fault management and performance management functions at the ATM
management-plane (M-plane) layer.
Note Current OAM implementation supports only the fault management function, which includes
connectivity verification and alarm surveillance.
The ATM switch router fully supports the following ATM OAM cell flows:
• F4 flows—OAM information flows between network elements used within virtual paths to report an
unavailable path or a virtual path (VP) that cannot be guaranteed.
• F5 flows—OAM information flows between network elements used within virtual connections to
report degraded virtual channel (VC) performance such as late arriving cells, lost cells, and cell
insertion problems.
You can configure both F4 and F5 flows as either end-to-end or segment-loopback, and they can be used
with alarm indication signal (AIS) and remote defect indication (RDI) functions.
Note Cells can be sent either on demand or periodically to verify link and connection integrity.
In addition to the standard OAM functions, the ATM switch router can also send OAM pings. See the
“Determining Network Connectivity” section on page 5-5. Using OAM cells containing the ATM node
addresses or IP addresses of intermediate switch routers, you can determine the integrity of a chosen
connection at any intermediate point along that connection. With this information, you can debug and
troubleshoot the network connection.
OAM Operation
OAM software implements ATM Layer F4 and F5 OAM fault management functions. OAM performs
standard loopback (end-to-end or segment) and fault detection and notification (AIS and RDI) for each
connection. It also maintains a group of timers for the OAM functions. When there is an OAM state
change such as loopback failure, OAM software notifies the connection management software. The
network operator can enable or disable OAM operation for the following ATM switch router
components:
• The entire ATM switch router
• A specific ATM interface
• Each ATM connection
OAM AIS, RDI, and loopback operations are enabled or disabled for the entire switch router using the
atm oam command in global configuration mode. Use the atm oam command in interface mode to
configure OAM on a specific connection. For more information about configuring OAM operations,
refer to the “Configuring Operation, Administration, and Maintenance” chapter in the
ATM Switch Router Software Configuration Guide.