Specifications

17-35
System Management Software Configuration Guide for Cisco IE 2000U and Connected Grid Switches
Chapter 17 Configuring Ethernet OAM, CFM, and E-LMI
Configuring Ethernet OAM
OAM Features
These OAM features are defined by 802.3ah:
• Discovery identifies devices in the network and their OAM capabilities. It uses periodic OAM PDUs
to advertise OAM mode, configuration, and capabilities; PDU configuration; and platform identity.
An optional phase allows the local station to accept or reject the configuration of the peer OAM
entity.
• Link monitoring detects and indicates link faults under a variety of conditions and uses the event
notification OAM PDU to notify the remote OAM device when it detects problems on the link. Error
events include when the number of symbol errors, the number of frame errors, the number of frame
errors within a specified number of frames, or the number of error seconds within a specified period
exceed a configured threshold.
• Remote failure indication conveys a slowly deteriorating quality of an OAM entity to its peers by
communicating these conditions: Link Fault means a loss of signal, Dying Gasp means an
unrecoverable condition, and Critical Event means an unspecified vendor-specific critical event. The
switch can receive and process but not generate Link Fault or Critical Event OAM PDUs. It can
generate Dying Gasp OAM PDUs to show when Ethernet OAM is disabled, the interface is shut
down, the interface enters the error-disabled state, or the switch is reloading. It also supports Dying
Gasp PDUs based on loss of power.
• Remote loopback mode to ensure link quality with a remote peer during installation or
troubleshooting. In this mode, when the switch receives a frame that is not an OAM PDU or a pause
frame, it sends it back on the same port. The link appears to the user to be in the up state. You can
use the returned loopback acknowledgement to test delay, jitter, and throughput.
Note Another way to test connectivity and ensure that a remote device is reachable is to configure
Ethernet loopback. See the “Enabling Ethernet Loopback” section on page 17-47.
OAM Messages
Ethernet OAM messages or PDUs are standard length, untagged Ethernet frames between 64 and 1518
bytes. They do not go beyond a single hop and have a maximum transmission rate of 10 OAM PDUs per
second. Message types are information, event notification, loopback control, or vendor-specific OAM
PDUs.
Configuring Ethernet OAM
• Default Ethernet OAM Configuration, page 17-36
• Ethernet OAM Configuration Guidelines, page 17-36
• Enabling Ethernet OAM on an Interface, page 17-36
• Enabling Ethernet OAM Remote Loopback, page 17-38
• Configuring Ethernet OAM Link Monitoring, page 17-39
• Configuring Ethernet OAM Remote Failure Indications, page 17-42
• Configuring Ethernet OAM Templates, page 17-43