How does MPLS Layer 3 VPN function?
How does MPLS Layer 3 VPN function?
MPLS Layer 3 VPN functions by PE (Provider Edge) devices labeling packets received from CE (Customer Edge) devices with a label learned from the source PE device that corresponds to the VPN forwarding table entry. This labeled packet is then transported across the provider network to the destination PE device. Upon arrival, the label is used to determine the correct egress interface to forward the packet towards the destination CE device. This accurately describes how MPLS Layer 3 VPN uses labels to route packets across a provider network, ensuring the correct delivery paths.
I think B may be correct- the label in question being the VPN label NOT the MPLS label which would have being removed by the previous router in the LSP.
I think C is to vague, so i agree, the outer label is removed still having the inner (VPN) label. Anyway, C sounds best to me
MPLS Layer 3 VPN operates by using MPLS labels to distinguish and forward packets between Customer Edge (CE) devices across the Provider Edge (PE) devices. When a packet is received by a PE device from a CE device, the PE device labels the packet with a label that corresponds to the VPN forwarding table entry learned from the source PE device. This labeled packet is then forwarded across the provider network to the destination PE device, which uses the label to determine the correct egress interface towards the destination CE device. So, option C accurately describes the function of MPLS Layer 3 VPN.
Guess B is ok as bk989 specified in the cisco doc
Answer is C according to cisco documentation: hen the destination PE device receives the labeled packet, it pops the label and uses it to direct the packet to the correct CE device https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/mp_l3_vpns/configuration/15-mt/mp-l3-vpns-15-mt-book/mp-bgp-mpls-vpn.html
Actually this looks like B
Indeed, the doc link clarifies using B as an answer.