Purpose of the FP sSID?
First, this FP whitepaper is amazing: http://www.cisco.com/c/en/us/products/collateral/switches/nexus-7000-series-switches/white_paper_c11-687554.html?cachemode=refresh
However, I'm still left puzzled about sSIDs in VPC+ domains, because it seems to serve the same function as the LID. The LID allows for PHP behavior and saves the edge switch from performing a MAC look-up when it receives a frame destined for the CE domain. According to this document, the sSID identifies the VPC interface for the same purpose. It then says that the LID is a shared value between the peers on a per-VPC basis, whereas the sSID is different.
What does the switch do with the sSID value?
Does it react differently if the packet is destined for its own VPC interface vs its peer's?
If used for PHP, what does the LID do for us?