8-2
ATM Switch Router Software Configuration Guide
OL-7396-01
Chapter8 Configuring Operation, Administration, an d Maintenance
OAM Overview
Both F4 and F5 flows can be configured as either end-to-end or segment-loopback and used w ith alarm
indication signal (AIS) and remote defect indication (RDI) functions. An AIS is a signal transmitt ed
downstream informing the destination that an upstream failure has been detected. An RDI signal
indicates that a failure has occurred at the far end of an ATM network.
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. OAM cells
containing the ATM node addresses or IP addresses of intermediate switches allow network
administrators to determine the integrity of a chosen connection at anyintermediate point along the
connection, allowing for network connection debugging and troubleshooting.
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 func tions. 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 switch components:
•The entire switch
•A specific ATM interface
•A specific ATM connection
If OAM operation is disabled, outgoing OAM cells (AIS, RDI and loopbacks) are not generated and AIS
and RDI cells that arrive at connection endpoints 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 an d 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 switch software.
The hardware can perform the following functions on OAM cells :
•Intercept—Intercepted to the CPU queue and processed by the ATM switch router software
•Relay—Relayed along with user cell by hardware without any software processing
•Discard—Discarded by hardware
An ATM connection consists of a group of network points that form the edges of each ATM switch or
end system.
Each point can be one of the following:
•Connection end point—The end of a connection where the user ATM cells are terminated
•Segment end point—The end of a connection segment
•Connecting point—The middle point of a connection segment
The following sections describe the OAM tasks:
•Configuring OAM Functions, page 8-3
•Checking the ATM Connection (Catalyst 8540 MSR), page 8-5
•Checking the ATM Connection (Catalyst 8510 MSR and LightStream 1010), page 8-5
•Displaying the OAM Configuration, page 8-6