1) MPLS QoS uses the EXP field in the MPLS encapsulation header or labels to identify packets and determine their forwarding behaviors, allowing up to 8 differentiated services. This can partially map to IP QoS which uses the DSCP field. 2) There are two approaches for mapping between MPLS QoS and IP QoS - E-LSP which maps to at most 8 PHBs using the EXP field, and L-LSP which allows mapping to any number of PHBs using labels. 3) MPLS QoS can be combined with IntServ to provide end-to-end QoS for individual flows but lacks scalability, or with DiffServ