The network QoS policy shown below is applied properly to a Nokia 7750 SR acting as a transit Label Switch Router (LSR) for a given MPLS tunnel. A packet is received inside the MPLS tunnel with EXP=4, dot1p=4, and DSCP=AF. Which forwarding class is assigned to this packet?
The correct answer is AF. According to the QoS policy shown, when a packet is received with an EXP value of 4, it is mapped to the forwarding class 'AF' (lsp-exp 4 fc af profile out). The router is acting as a Label Switch Router (LSR), so the EXP value takes precedence over DSCP and dot1p values. Therefore, the packet will be assigned to the forwarding class 'AF'.
The correct answer is C, as it is stated the router is an LSR, there the "ler-use-dscp" is not used, EXP stills have priority over DSCP