Service Entities
Page 52 7210 SAS M Services Guide
Ethernet Ring Sub-Rings
Ethernet Sub-Rings offer a dual redundant way to interconnect rings. The 7210 SAS supports Sub-
Rings connected to major rings and a sub-ring connected to a VPLS (LDP based) for access rings
support in VPLS networks. Figure 9 illustrates a Major ring and Sub Ring scenario. In this
scenario, any link can fail in either ring (ERP1 or ERP2) and each ring is protected. Furthermore,
the sub ring (ERP2) relies on the major Ring (ERP1) as part of its protection for the traffic from C
and D. The nodes C and D are configured as inter connection nodes.
RPL Owner Node
ERP1
RPL Node
RPL Link ERP1
Ring Link
7450
7450
7450
7450
A
B
CD
a
a
b
b
b
a
7450 7450
EF
a
b
sub-ring port
b
a
RPL Link ERP2
RPL Owner Node
ERP2
ERP1
ERP2
b
a
sub-ring port
Inter connection Link
Ring APS – ERP – Control Channel
Ring Data Channels
Virtual channel
Or Non-Virtual channel
a
a
RPL Owner Node
ERP1
RPL Node
RPL Link ERP1
Ring Link
74507450
74507450
74507450
74507450
A
B
CD
a
a
b
b
b
a
74507450 74507450
EF
a
b
sub-ring port
b
a
RPL Link ERP2
RPL Owner Node
ERP2
ERP1
ERP2
b
a
sub-ring port
Inter connection Link
Ring APS – ERP – Control Channel
Ring Data Channels
Virtual channel
Or Non-Virtual channel
a
a