System Manual 3. System Architecture
76.7300FP11/2, Rev A 8/09 Page 2-21
3.29 Link aggregation can be used for facility protection on the 802.3 MAC
facilities. The link aggregation control protocol (LACP) defined in 802.3 provides a
means for this protection. LACP exchange configuration information between two
LAG entities and reconfigure the LAG entities accordingly.
3.30 For example, if one LAG entity detects link failure, its configuration is
changed due to the failed link, and the LAG entity stops transmitting frame to the
failed link, starts the timer and informs this new configuration to its partner via
LACP frames. The peer LAG entities then stop transmitting/receiving the frame
from the failed link, and restart the timers. After the timer expires, the LAG entity
starts to re-distribute the traffic on the healthy members.
Ethernet OAM Support
3.31 The Tellabs 7300 NEs provide the following 802.3ah support. Refer to
Table 3.7, page 2-21.
3.32 IEEE 802.3ah defines a mechanism for remote intrusive facility loopback.
The overall process is as follows:
1. After the local OAM client receives the initiating loopback command, it
stops forwarding traffic and sends Loopback Control OAMPDU to the
remote OAM client.
2. When the remote OAM client receives the Loopback Control
OAMPDU, it stops forwarding traffic, enters loopback mode and sends
Information OAMPDU indicating it is in loopback mode to the local
OAM client that initiated loopback.
3. When the local OAM client receives the Information Control OAMPDU,
it re-starts forwarding traffic.
3.33 During loopback, all frames (including slow protocol frames) from local NE
to remote NE, except OAMPDU frames, will be loopbacked by the remote OAM
client. After the loopbacked frames are received by the local NE, they are parsed
by the OAM sublayer of the local NE. The OAM frames will be passed to the OAM
client, while other frames are discarded.
Table 3.7 802.3ah Link Monitoring
Standard/Feature Details
Link status Remote fault
Dying gasp generation
Dying gasp detection/annunciation
Loopback Local loopback
Initiate remote loopback
Respond to remote loopback request