VPLS Features
Split Horizon SAP Groups and Split Horizon Spoke SDP Groups
Within the context of VPLS services, a loop-free topology within a fully meshed VPLS core is
achieved by applying a split-horizon forwarding concept that packets received from a mesh SDP
are never forwarded to other mesh SDPs within the same service. The advantage of this approach
is that no protocol is required to detect loops within the VPLS core network.
In applications such as DSL aggregation, it is useful to extend this split-horizon concept also to
groups of SAPs and/or spoke SDPs. This extension is referred to as a split horizon SAP group or
residential bridging.
Traffic arriving on a SAP or a spoke SDP within a split horizon group will not be copied to other
SAPs and spoke SDPs in the same split horizon group (but will be copied to SAPs / spoke SDPs in
other split horizon groups if these exist within the same VPLS).
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