CS6250 COMPUTER NETWORK EXAM 2
QUESTIONS WITH VERIFIED ANSWERS 2026 |
Revision Notes | A+ Verified
• 4 SDN applications in wide area traffic delivery -✓✓application specific peering,
inbound traffic engineering, wide-area server load balancing, redirection through
middleboxes
• 2 types of policies in SDX -✓✓inbound and outbound
• SDX implements 4 types of apps -✓✓application-specific, traffic engineering, traffic
load balancing, and traffic redirection through middleboxes
• 2 limitations of BGP that SDN helps with -✓✓routing on dest IP prefix, networks have
little control over e2e paths
• 5 applications of SDN -✓✓traffic engineering, mobility and wireless, measurement and
monitoring, security and dependability, data center networking
• 2 main ops of P4 forwarding model -✓✓configure, populate
• 3 goals of P4 -✓✓reconfigurability, protocol independence, target independence
• example of a distributed controller -✓✓ONOS
• 2 ways for distribution to occur in distributed controllers -✓✓centralized cluster of
nodes or a physically distributes set of elements
• 2 categories of SDN controllers -✓✓centralized and distributed
• 6 core controller functions -✓✓topology, stats, notifications, device mgmt, shortest
path forwarding, security
• 2 functions of network layer -✓✓forwarding (data), routing (control)
• Most important task of router -✓✓transfer received packet from input link interface to
appropriate output link interface
• What are the main components of a router? -✓✓input/output ports, switching fabric,
and routing processor
, • Three input port functionalities -✓✓physically terminate incoming links to router, data
link processing unit decapsulates packets, perform lookup function
• switching fabric functionality -✓✓moves packets from input to output ports and makes
connection between them
• three types of switching fabrics -✓✓memory, bus, crossbar
• 3 output port functionalities -✓✓receive and queue packets, data link processing
(encapsulation), line termination
• three control plane functions -✓✓implementing routing protocols, maintaining routing
tables, computing forwarding table
• where are control plane functions implemented? -✓✓routing processor software
• three most time sensitive tasks in router -✓✓lookup, switching, scheduling/queueing
• what is used to resolve ambiguities in lookup? -✓✓longest prefix matching algorithm
• what is packet classification as part of the lookup function? -✓✓lookup based on dest
IP, source IP, port and other criteria
• Modern fast routers use what kind of switches? -✓✓crossbar
• three less time sensitive tasks in router -✓✓header validation and checksum, route
processing, and protocol processing
• protocol processing must implement what three things? -✓✓simple network mgmt
protocol (SNMP), TCP and UDP, Internet control message protocol (ICMP)
• three different types of switching -✓✓via memory, via bus, and via interconnection
network
• six challenges routers face -✓✓fundamental problems(bandwidth and internet
population scaling, services at high speeds), bottlenecks, longest prefix matching,
service differentiation, switching limitations, bottlenecks about services
• 3 ways to denote prefix -✓✓dot decimal, slash notation, masking
• biggest problem of unibit tries -✓✓number of memory accesses that it requires for a
lookup
• how many children does each node have in a multibit trie -✓✓2K, where K is a stride
QUESTIONS WITH VERIFIED ANSWERS 2026 |
Revision Notes | A+ Verified
• 4 SDN applications in wide area traffic delivery -✓✓application specific peering,
inbound traffic engineering, wide-area server load balancing, redirection through
middleboxes
• 2 types of policies in SDX -✓✓inbound and outbound
• SDX implements 4 types of apps -✓✓application-specific, traffic engineering, traffic
load balancing, and traffic redirection through middleboxes
• 2 limitations of BGP that SDN helps with -✓✓routing on dest IP prefix, networks have
little control over e2e paths
• 5 applications of SDN -✓✓traffic engineering, mobility and wireless, measurement and
monitoring, security and dependability, data center networking
• 2 main ops of P4 forwarding model -✓✓configure, populate
• 3 goals of P4 -✓✓reconfigurability, protocol independence, target independence
• example of a distributed controller -✓✓ONOS
• 2 ways for distribution to occur in distributed controllers -✓✓centralized cluster of
nodes or a physically distributes set of elements
• 2 categories of SDN controllers -✓✓centralized and distributed
• 6 core controller functions -✓✓topology, stats, notifications, device mgmt, shortest
path forwarding, security
• 2 functions of network layer -✓✓forwarding (data), routing (control)
• Most important task of router -✓✓transfer received packet from input link interface to
appropriate output link interface
• What are the main components of a router? -✓✓input/output ports, switching fabric,
and routing processor
, • Three input port functionalities -✓✓physically terminate incoming links to router, data
link processing unit decapsulates packets, perform lookup function
• switching fabric functionality -✓✓moves packets from input to output ports and makes
connection between them
• three types of switching fabrics -✓✓memory, bus, crossbar
• 3 output port functionalities -✓✓receive and queue packets, data link processing
(encapsulation), line termination
• three control plane functions -✓✓implementing routing protocols, maintaining routing
tables, computing forwarding table
• where are control plane functions implemented? -✓✓routing processor software
• three most time sensitive tasks in router -✓✓lookup, switching, scheduling/queueing
• what is used to resolve ambiguities in lookup? -✓✓longest prefix matching algorithm
• what is packet classification as part of the lookup function? -✓✓lookup based on dest
IP, source IP, port and other criteria
• Modern fast routers use what kind of switches? -✓✓crossbar
• three less time sensitive tasks in router -✓✓header validation and checksum, route
processing, and protocol processing
• protocol processing must implement what three things? -✓✓simple network mgmt
protocol (SNMP), TCP and UDP, Internet control message protocol (ICMP)
• three different types of switching -✓✓via memory, via bus, and via interconnection
network
• six challenges routers face -✓✓fundamental problems(bandwidth and internet
population scaling, services at high speeds), bottlenecks, longest prefix matching,
service differentiation, switching limitations, bottlenecks about services
• 3 ways to denote prefix -✓✓dot decimal, slash notation, masking
• biggest problem of unibit tries -✓✓number of memory accesses that it requires for a
lookup
• how many children does each node have in a multibit trie -✓✓2K, where K is a stride
