CS 6250 Exam 2/79 questions & Answers
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