Signaling MSD using BGP-LS (RFC8814)

We partially support RFC 8814, Signaling Maximum SID Depth (MSD) Using the Border Gateway Protocol - Link State. Currently, we support signalling Maximum SID Depth (MSD) using IS-IS for both SR-MPLS and SRv6. For non-SR networks, this will reflect the maximum label depth. A controller in a segment routing network learns the MSD of the participating router and computes the SR path. The controller ensures that the label stack is not greater than what the routers can support.