MPLS - Fundamentals Walkthrough QUESTIONS AND ANSWERS 100%ACCURATE.
What does MPLS Stand For? - ✅✅Multiprotocol Label Switching
"Label Switching" means that MPLS _______________ rather than _____________ in
a Service Provider Core - ✅✅Domain Switches
Routes
The MPLS Label Binding Table Lookup Process is Simpler, due where and how MPLS
is implemented, what is simpler about the lookup process. - ✅✅It looks for an exact
match, rather than longest. This is possible because MPLS is implemented in specific
networks where there are less addresses, and all addresses are known.
Is the speed argument still valid in comparing the two softwares? - ✅✅No
What technological advancements invalidate the speed argument in comparing the two
softwares? - ✅✅Modern manufacturing and Application-Specific Integrated Circuits
(ASICs)
Considering that speed is no longer relevant, why might MPLS be used - ✅✅Avoiding
Congestion
How can an engineer use MPLS to better avoid congestion - ✅✅They can design the
label switched paths to better balance the traffic load
What might traffic engineering provide the ability to do? - ✅✅Engineer the traffic such
that network resources are optimized
What is the flaw with ECMP? - ✅✅Not scalable nor manageable for large networks?
What technology is used if an LSP goes down? - ✅✅LSP Fast Reroute
What does the term BGP-Free MPLS Core Mean? - ✅✅External traffic can be label
switched in such a manner that does not distinguish it (MPLS Solves Racism)
What is a Label Edge Router - ✅✅It's the router that lies at the edge of the MPLS
network and does the pushing and popping
What is a Label Header? - ✅✅A fixed length entity that gets pushed onto a packet at
the iLER
What is an LSP? - ✅✅Label Switched Path
, What is the difference between LSP and Transport Tunnel? - ✅✅No difference, they
are synonymous
What is a forwarding Equivalence Path? - ✅✅Group of packets that are forwarded in
the exact same manner over hte same path with the same treatment
What gets built in the MPLS Control Plane? - ✅✅Label Information Base (LIB)
When Label Binding Information Is Transferred to the Data Plane, in what is it stored? -
✅✅LFIB - Label Forwarding Information Base
How do you create a bidirectional LSP? - ✅✅You can't, you need two LSPs
How does a router know which label to use for downstream transmission - ✅✅That
information is stored in the Forwarding Database
Why might a single data packet or frame carry multiple MPLS Labels? -
✅✅Differentiate different types of customers and/or services
Where are MPLS Labels inserted in the network stack? - ✅✅Between Layer 2
Header and Data
What is the order of MPLS Labels in the network stack? - ✅✅L1 Header, L2 Header,
Label, L3 Header...
What is the maximum number of labels supported - ✅✅Technically infinite, Actually it
is constrained to the physical interface's maximum packet size
Take a gander at what a service instance might be - ✅✅A virtual software entity in
the service router
Is the service label the bottom or top label? - ✅✅Bottom - Remember on a stack you
push and pop from the top of the stack, just like a stack of books
If the service is the bottom label, then what must the transport label be - ✅✅Top
What is a service label? - ✅✅It is a label that indicates which service is being used
What is a transport label? - ✅✅It is the label that is being used to transport the data
across the LSP
Why then, is the service label the bottom label - ✅✅because of the nature of the
stack, the top label is what will be popped. And so at every hop the transport label will
be popped
What does MPLS Stand For? - ✅✅Multiprotocol Label Switching
"Label Switching" means that MPLS _______________ rather than _____________ in
a Service Provider Core - ✅✅Domain Switches
Routes
The MPLS Label Binding Table Lookup Process is Simpler, due where and how MPLS
is implemented, what is simpler about the lookup process. - ✅✅It looks for an exact
match, rather than longest. This is possible because MPLS is implemented in specific
networks where there are less addresses, and all addresses are known.
Is the speed argument still valid in comparing the two softwares? - ✅✅No
What technological advancements invalidate the speed argument in comparing the two
softwares? - ✅✅Modern manufacturing and Application-Specific Integrated Circuits
(ASICs)
Considering that speed is no longer relevant, why might MPLS be used - ✅✅Avoiding
Congestion
How can an engineer use MPLS to better avoid congestion - ✅✅They can design the
label switched paths to better balance the traffic load
What might traffic engineering provide the ability to do? - ✅✅Engineer the traffic such
that network resources are optimized
What is the flaw with ECMP? - ✅✅Not scalable nor manageable for large networks?
What technology is used if an LSP goes down? - ✅✅LSP Fast Reroute
What does the term BGP-Free MPLS Core Mean? - ✅✅External traffic can be label
switched in such a manner that does not distinguish it (MPLS Solves Racism)
What is a Label Edge Router - ✅✅It's the router that lies at the edge of the MPLS
network and does the pushing and popping
What is a Label Header? - ✅✅A fixed length entity that gets pushed onto a packet at
the iLER
What is an LSP? - ✅✅Label Switched Path
, What is the difference between LSP and Transport Tunnel? - ✅✅No difference, they
are synonymous
What is a forwarding Equivalence Path? - ✅✅Group of packets that are forwarded in
the exact same manner over hte same path with the same treatment
What gets built in the MPLS Control Plane? - ✅✅Label Information Base (LIB)
When Label Binding Information Is Transferred to the Data Plane, in what is it stored? -
✅✅LFIB - Label Forwarding Information Base
How do you create a bidirectional LSP? - ✅✅You can't, you need two LSPs
How does a router know which label to use for downstream transmission - ✅✅That
information is stored in the Forwarding Database
Why might a single data packet or frame carry multiple MPLS Labels? -
✅✅Differentiate different types of customers and/or services
Where are MPLS Labels inserted in the network stack? - ✅✅Between Layer 2
Header and Data
What is the order of MPLS Labels in the network stack? - ✅✅L1 Header, L2 Header,
Label, L3 Header...
What is the maximum number of labels supported - ✅✅Technically infinite, Actually it
is constrained to the physical interface's maximum packet size
Take a gander at what a service instance might be - ✅✅A virtual software entity in
the service router
Is the service label the bottom or top label? - ✅✅Bottom - Remember on a stack you
push and pop from the top of the stack, just like a stack of books
If the service is the bottom label, then what must the transport label be - ✅✅Top
What is a service label? - ✅✅It is a label that indicates which service is being used
What is a transport label? - ✅✅It is the label that is being used to transport the data
across the LSP
Why then, is the service label the bottom label - ✅✅because of the nature of the
stack, the top label is what will be popped. And so at every hop the transport label will
be popped
