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300-410 · Question #92
300-410 Question #92: Real Exam Question with Answer & Explanation
The correct answer is C: Using a number that has been specified in a label. In an MPLS domain, packets are forwarded based on the labels attached to them, not on their IP headers.
Layer 3 Technologies
Question
How are packets forwarded in an MPLS domain?
Options
- AUsing the destination IP address of the packet
- BUsing the source IP address of the packet
- CUsing a number that has been specified in a label
- DUsing the MAC address of the frame
Explanation
In an MPLS domain, packets are forwarded based on the labels attached to them, not on their IP headers.
Common mistakes.
- A. Forwarding based on the destination IP address is characteristic of traditional IP routing, not the label-based forwarding within an MPLS core.
- B. The source IP address of a packet is generally not used for forwarding decisions in any standard network topology.
- D. MAC addresses are used for Layer 2 forwarding within a local segment, but within an MPLS domain, the forwarding decision at the MPLS layer is made using labels, although the MPLS frames are carried over Layer 2.
Concept tested. MPLS packet forwarding mechanism
Topics
#MPLS#Label Switching#Packet Forwarding
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