Figure 9: 0-4 G.8032 Sub-Ring - Alcatel-Lucent 7210 SAS M Service Manual

MC-LAG
Sub-Rings and Major Rings run similar state machines for the ring logic, however there are some
differences. When Sub-Rings protect a link, the flush messages are propagated to the major ring.
(A special configuration allows control of this option on the 7210 SAS.) When major rings change
topology, the flush is propagated around the major ring and does not continue to any sub-rings.
The reason for this is that Major Rings are completely connected but Sub-Rings are dependent on
another ring or network for full connectivity. The topology changes need to be propagated to the
other ring or network usually. Sub-Rings offer the same capabilities as major rings in terms of
control and data so that all link resource may be utilized.
7210 SAS M Services Guide
Sub Ring
Major Ring
RPL
CE CE

Figure 9: 0-4 G.8032 Sub-Ring

Major Ring
Sub Ring
Sub Ring
Major Ring
CE CE
Services
PBB BCB Function
PBB BEB Function
QinQ Switch
Major Ring
CE CE
OSSG532
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