Top MPLS Interview Questions (2024)
What is MPLS?
How does MPLS work?
What is the role of labels in MPLS?
What are the benefits of MPLS?
What are the different label distribution protocols in MPLS?
What is the difference between an MPLS label and a network layer (IP) address?
What is an MPLS LSP?
What is MPLS VPN?
What is the difference between MPLS and IP routing?
What is MPLS Traffic Engineering?
What is MPLS Fast Reroute (FRR)?
How does MPLS support Quality of Service (QoS)?
What are the MPLS label operations?
What is the difference between MPLS and VPLS?
What is MPLS multicast?
Q: What is MPLS?
Ans:
In computer networks, MPLS (Multiprotocol Label Switching) is a protocol for effective packet forwarding. It use labels to identify and forward packets, enabling routers to decide whether to forward a packet by looking only at the label rather than the whole packet header.
Q: How does MPLS work?
Ans:
At the ingress router, MPLS adds a label to each packet. The packet's forwarding path through the network is determined by the label. The label is used by routers along the way to decide how to forward packets, resulting in quicker and more effective packet forwarding.
Q: What is the role of labels in MPLS?
Ans:
For packet forwarding, routers use labels in MPLS as identifiers to determine the next hop. Label-switched paths (LSPs) are established through the network by assigning labels at the ingress router.
Q: What are the benefits of MPLS?
Ans:
A few advantages of MPLS include better network performance, traffic engineering capabilities, effective resource management, support for numerous network protocols, and increased Quality of Service (QoS) features.
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Q: What are the different label distribution protocols in MPLS?
Ans:
LDP, RSVP-TE, and BGP with MPLS extensions are just a few of the label distribution protocols that are supported by MPLS. RSVP-TE is a resource reservation protocol with traffic engineering extensions.
Q: What is the difference between an MPLS label and a network layer (IP) address?
Ans:
A network layer address (IP address) is a brief identifier used for packet forwarding within an MPLS network while an MPLS label is used to identify devices and networks in an IP-based network.
Q: What is an MPLS LSP?
Ans:
Packets go along a preset route over an MPLS network known as an MPLS LSP (Label-Switched Path). Labelling packets and forwarding them in accordance with those labels creates LSPs.
Q: What is MPLS VPN?
Ans:
A shared MPLS infrastructure can be used with MPLS VPN to create virtual private networks. It maintains privacy and isolation while delivering secure and effective connectivity across various sites of an organization.
Q: What is the difference between MPLS and IP routing?
Ans:
While IP routing runs at layer 3, MPLS is a layer 2.5 technology that operates between layer 2 (Data Link Layer) and layer 3 (Network Layer). IP routing uses IP addresses, whereas MPLS uses labels to forward packets.
Q: What is MPLS Traffic Engineering?
Ans:
An MPLS network's resource utilization and traffic flow can be improved by using a set of techniques called MPLS Traffic Engineering (MPLS TE). It makes it possible to manage bandwidth allocation, traffic pathways, and QoS guarantees.
Q: What is MPLS Fast Reroute (FRR)?
Ans:
A technique called MPLS Fast Reroute enables the rapid restoration of traffic in the case of a network loss. By creating backup paths that may be quickly activated when failures happen, it protects against connection or node failures.
Q: How does MPLS support Quality of Service (QoS)?
Ans:
By enabling the categorization and prioritization of packets based on their labels, MPLS supports QoS. Packets can be given different classes of service, allowing the network to provide distinct QoS guarantees for various types of traffic.
Q: What are the MPLS label operations?
Ans:
Label imposition (adding a label on a packet), label swapping (replacing a label with a new one), and label popping (removing the label at the egress router) are all examples of MPLS label operations.
Q: What is the difference between MPLS and VPLS?
Ans:
While VPLS (Virtual Private LAN Service) is a layer 2 VPN technology that simulates a LAN over an MPLS network, MPLS is a label-based forwarding technology that functions at the packet level. With VPLS, LAN capabilities may be extended to locations across the globe.
Q: What is MPLS multicast?
Ans:
An approach known as MPLS multicast allows for the effective delivery of multicast traffic over an MPLS network. It replicates and forwards multicast messages to numerous destinations using label-switched multicast trees (LSMTs).