Ethernet OAM works on Ethernet services and use a combination of unicast with learning and multicast addresses. SPB on SR OS supports both unicast and multicast forwarding, but with no learning and unicast and multicast may take different paths. In addition, SR OS SPB control plane offers a wide variety of show commands. The SPB IS-IS control plane takes the place of many Ethernet OAM functions. SPB IS-IS frames (Hello and PDU and so on) are multicast but they are per SPB interface on the control B-VPLS interfaces and are not PBB encapsulated.
All Client Ethernet OAM is supported from I-VPLS interfaces and PBB Epipe interfaces across the SPB domain. Client OAM is the only true test of the PBB data plane. The only forms of Eth-OAM supported directly on SPB B-VPLS are Virtual MEPS (vMEPs). Only CCM is supported on these vMEPs; vMEPs use a S-TAG encapsulation and follow the SPB multicast tree for the specified B-VPLS. Each MEP has a unicast associated MAC to terminate various ETH-CFM tools. However, CCM messages always use a destination Layer 2 multicast using 01:80:C2:00:00:3x (where x = 0 to 7). vMEPs terminate CCM with the multicast address. Unicast CCM can be configured for point to point associations or hub and spoke configuration but this would not be typical (when unicast addresses are configured on vMEPs they are automatically distributed by SPB in IS-IS).
Up MEPs on services (I-VPLS and PBB Epipes) are also supported and these behave as any service OAM. These OAM use the PBB encapsulation and follow the PBB path to the destination.
Link OAM or 802.1ah EFM is supported below SPB as standard. This strategy of SPB IS-IS and OAM gives coverage.
| OAM origination | Data plane support | Comments |
|---|---|---|
PBB-Epipe or Customer CFM on PBB Epipe. Up MEPs on PBB Epipe. |
Fully Supported. Unicast PBB frames encapsulating unicast/multicast. |
Transparent operation. Uses Encapsulated PBB with Unicast B-MAC address. |
I-VPLS or Customer CFM on I-VPLS. Up MEPs on I-VPLS. |
Fully Supported. Unicast/Multicast PBB frames determined by OAM type. |
Transparent operation. Uses Encapsulated PBB frames with Multicast/Unicast B-MAC address. |
vMEP on B-VPLS Service. |
CCM only. S-Tagged Multicast Frames. |
Ethernet CCM only. Follows the Multicast tree. Unicast addresses may be configured for peer operation. |
In summary SPB offers an automated control plane and optional Eth-CFM/Eth-EFM to allow monitoring of Ethernet Services using SPB. B-VPLS services PBB Epipes and I-VPLS services support the existing set of Ethernet capabilities.