Top 100+ MPLS Interview Questions – [UPDATED 2023]

Question 1: What is MPLS?
Question 2: Why MPLS is called as Multi-Protocol Label Switching?
Question 3: Why MPLS is called as Layer 2.5 Technology?
Question 4: What are the applications of MPLS?
Question 5: What are the advantages of MPLS?
Question 6: What is LDP?
Question 7: What is MPLS and why it is being so popular in short time?
Question 8: What is the protocol used by MPLS?
Question 9: MPLS works on which layer?
Question 10: What is the difference between P and PE router?
Question 11: Can I make my PE router as P?
Question 12: Two routers are having 4 equal cost links, how many LDP sessions will be established?
Question 13: My LDP router id, OSPF router id and BGP router id is different, will it work to forward the traffic of customers or not?
Question 14: What is Penultimate Hop Popping and why it is required? Which router performs the PHP function?
Question 15: I am receiving aggregate label, what does it mean?
Question 16: What are the different types of labels?
Question 17: How to make customer route unique?
Question 18: What is the difference between RD and RT?
Question 19: Can I assign a same RD to two different customers?
Question 20: Is RD travels in route update?
Question 21: My customer is having three branches and all are attached to three different PEs, In this case can I use the different VRF names?
Question 22: What is downstream on demand?
Question 23: How to filter MPLS labels?
Question 24: What is the default range of MPLS labels in Cisco routers? How to extend that range?
Question 25: Without route reflector can I implement MPLS?
Question 26: What is the difference between VPNv4 and IPv4 address family?
Question 27: What is MP-iBGP? Can we use normal BGP in lieu of MP-iBGP?
Question 28: What is LIB, LFIB?
Question 29: What is CEF and without enabling CEF, can we make MPLS work?
Question 30: I am receiving end to end customer routes on various PE but not able to ping those routes, what’s could be the problem?
Question 31: What is explicit null and implicit null?
Question 32: Default timers of LDP?
Question 33: Does LDP require OSPF, IS-IS or BGP?
Question 34: In neighbor discovery command, I am receiving only xmit, what does it mean
Question 35: What is transport address?
Question 36: What is the RFC of MPLS?
Question 37: Why MPLS is called multi-protocol?
Question 38: What is the difference between MPLS, SSL and IPSec?
Question 39: I am using different vendor products and want to implement TDP, what type of challenges will you face?
Question 40: What is the MFA Forum?
Question 41: What MPLS related mailing lists are there and what are they used for?
Question 42: How did MPLS evolve?
Question 43: What problems does MPLS solve?
Question 44: What is the status of the MPLS standard?
Question 45: What is a Label?
Question 46: What is a Label Switch Path?
Question 47: What is a Label Distribution Protocol?
Question 48: What’s the difference between CR-LDP and RSVP-TE
Question 49: What is a “Forwarding Equivalency Class”?
Question 50: How are Label Switch Paths built?
Question 51: What other protocols does MPLS support besides IP?
Question 52: What are the differences between MPLS and ATM?
Question 53: Does MPLS replace ATM?
Question 54: What is “Ships in the night”?
Question 55: What does MPLS traffic engineering accomplish?
Question 56: What are the components of MPLS-TE?
Question 57: How does MPLS merge traffic flows?
Question 58: How loops are prevented in MPLS networks?
Question 59: How does MPLS perform failure recovery?
Question 60: What differences are there in running MPLS in OSPF versus IS-IS environments
Question 61: Can there be two or more Autonomous Systems within the same MPLS domain?
Question 62: How does MPLS enable VPNs?
Question 63: What alternatives are there for implementing VPNs over MPLS?
Question 64: What is the “Martini Draft’?
Question 65: What is a “Layer 2 VPN”?
Question 66: What is a Virtual Private LAN Service (VPLS)?
Question 67: Are MPLS-VPNs secure?
Question 68: What kinds of QoS protocols does MPLS support?
Question 69: How do I integrate MPLS and DiffServ?
Question 70: How do I integrate MPLS and ATM QoS?
Question 71: What is “Generalized MPLS” or “GMPLS”
Question 72: What are the components of GMPLS?
Question 73: What are the features of GMPLS?
Question 74: What are the “Peer” and “Overlay” models?
Question 75: What is the “Optical Internetworking Forum”?
Question 76: Can voice and video traffic be natively encapsulated into MPLS?
Question 77: How are MPLS networks managed?
Question 78: Are there any MPLS-specific MIBs?
Question 79: Is there open source MPLS code to test MPLS?
Question 80: What shows and conferences provide information on MPLS?
Question 81: Are there any labs that are performing MPLS interoperability testing?
Question 82: Does MPLS support IPv6?
Question 83: Can I use the existing IPv4 MPLS backbone for IPv6?
Question 84: Define various troubleshooting commands in MPLS?
Question 85: What is adjacency table?
Question 86: Difference between MPLS IP and MPLS Label Protocol LDP command?
Question 87: If MPLS get disable, will it harm my IGP or IPv4 traffic?
Question 88: What is MPLS-TP?
Question 89: What is downstream and upstream router in MPLS? Difference between MPLS and MPLS-TP?
Question 90: How does LDP Initializes?
Question 91: What is Cell Mode MPLS over ATM?
Question 92: Difference Between VC Based Multiplexing And Logical Link Control Encapsulation in ATM?
Question 93: Basics of ATM?
Question 94: ATM is packet or circuit switching?
Question 95: Is LDP Required for VPNv4 Labels?
Question 96: What will happen if you see your PE loopback in vpnv4 table?
Question 97: What is Bidirectional Forwarding Detection?
Question 98: Different types of Pseudo Wire?
Question 99: Modes of EoMPLS (Ethernet over MPLS)
Question 100: What is L2VPN over Metro Ethernet?
Question 101: What is E-VPN (Ethernet VPN)?
Question 102: What is FEC in traditional IP routing and MPLS?
Question 103: How does CEF understand overlapping of ip addresses?
Question 104: What is the difference between Optimum, Fast and CEF Switching?
Question 105: Define CEF FIB table entries.
Question 106: What is the port number used by LDP?
Question 107: What are the prerequisites to run MPLS?
Question 108: What is penultimate hop popping?
Question 109: What are the functions done by MPLS?
Question 110: What is the difference between Per Platform Label Space and Per Interface Label Space?
Question 111: Is summarization is recommended in MPLS?
Question 112: What is TTL Propagation in MPLS?
Question 113: What is LDP IGP Synchronization?
Question 114: What is the difference between Implicit Null and Explicit Null?