8031, ???Ethernet Protection Switching.??? So far, only point-to-point protection switching
has been approached. The basic idea is to have a network of bridge-like devices.
For each E-Line EVC, the network management system creates both a primary and
an alternate path through the network. The endpoints of the EVC use ITU-T Y.1731
Ethernet OAM to determine the operational state of each of the two paths, and use the
primary path if it is up and the secondary path if the primary path fails.
This means of offering provider services has not, so far, been integrated with the capabilities
of standard IEEE 802 bridges, and the details of the data plane supporting these
E-Line EVCs have not been fully determined within ITU-T. There are proponents for at
least two different approaches for the underlying data plane operation. The reader may
track the progress of these standards from the ITU-T websites for these two study groups:
www.itu.int/ITU-T/studygroups/com13 and www.itu.int/ITU-T/studygroups/com15.
Ethernet Bridging 417
Provider Backbone Bridge Traffic Engineering
The IEEE Standards Association has authorized the development of Project 802.
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