Regarding PW labels and tunnel labels, which of the following statements are correct?

PW labels are mainly used to distinguish PWs, but for CES services, because CES services do not support aggregation, there is no need to use PW labels

Tunnel label is mainly used for transmission in the tunnel, it mainly uses the tunnel label to establish MPLS tunnel

They are all based on MPLs tags

PW signing only needs negotiation between the source and sink network elements, and has nothing to do with the intermediate

tansit network elements