Handout 6

Question 1

These routes are manually configured by network administrators, have low system requirements, and apply to simple, stable, and small networks. The disadvantage of static routes is that they cannot automatically adapt to network topology changes and so require manual intervention

Answer 1

static routes

Question 2

are used only when packets to be forwarded do not match any routing entry in an IP routing table.

Answer 2

default routes

Question 3

On the Internet, routers need to exchange routing information in the interconnection of networks called

Answer 3

autonomous systems (AS or domains)

Question 4

The autonomous systems are connected together in the form of a network called

Answer 4

core network (backbone)

Question 5

meant to dynamically route data across a network that you fully control and maintain. Basically, interior protocols are meant to dynamically route data across a network that you fully control and maintain

Answer 5

interior gateway protocol (IGP)

Question 6

used to exchange routes between distinctly separate networks that you have no administrative control over. BGP is the routing protocol used on the Internet; therefore, the most common enterprise use is to run BGP on your internet edge when connecting to your ISP

Answer 6

exterior gateway protocol (EGP)

Question 7

determine good paths (routes) from senders to receivers through the network of routers

Answer 7

routing algorithms

Question 8

finds a path between the source and destination with the least cost

Answer 8

least-cost path

Question 9

path with the smallest number of links between the source and the destination

Answer 9

shortest path

Question 10

In this type of routing, all the routers send their neighboring routers

Answer 10

distance-vector routing protocol

Question 11

a commonly used distance vector routing that uses its routing metric to determine the best route or shortest path a packet has to traverse from the source to a destination over a network. RIP is a distance-vector IGP and has a preference of 100

Answer 11

routing information protocol (RIP)

Question 12

number of routers through which a packet passes to reach its destination

Answer 12

hop count

Question 13

In this type of routing, each of the routers sends the state of its own interfaces to all other routers only when there is a change to report. Each router uses the received information to recalculate the best path to each network and then saves this information in its routing table

Answer 13

link-state routing protocol

Question 14

description of the router interface

Answer 14

link-state (LS)

Question 15

the cost of sending data packets on the interface, expressed in the link state metric.

Answer 15

output cost

Question 16

these are other routers that are attached through the link-state

Answer 16

list of neighboring routers

Question 17

an OSPF data packet containing link-state and routing information that is shared with the other routers

Answer 17

link-state advertisement (LSA)

Question 18

a unit of data describing the local state of router’s interfaces and adjacencies. The collected LS advertisements of all routers and networks form the LSDB

Answer 18

link-state PDU

Question 19

a collection of all LS PDUs originated from the area’s routers. Each router advertises directly connected networks via LS POU.

Answer 19

link-state datebase (LSDB)

Question 20

a link-state routing protocol develope by the IETF in 1988 that is capable of quickly detecting topological changes within the autonomous system and establishing loop-free routes in a short period of time, with minimum additional communication overhead for negotiating topology changes between peering routers

Answer 20

open shortest path first (OSPF)

Question 21

a special data packet (message) that is sent out periodically from a router to establish and confirm network adjacency relationships to other routers in the OSPF

Answer 21

HELLO packet

Question 22

contains information, such as the destination IP address, cost, and next-hop IP address, which guides packet forwarding

Answer 22

OSPF routing table

Question 23

is the ISO name for a router, it is the communication between intermediate systems or routers

Answer 23

intermediate system (IS)

Question 24

a device on the network, such as a server or workstation (hosts)

Answer 24

end system (ES)

Question 25

a network service in the OSI stack

Answer 25

connection-less network service (CLNS)

Question 26

a layer-3 address for CLNS packets, this is like an IP address in the TCP/IP stack. IS-IS uses this to address for communication not IP addresses

Answer 26

network service access point (NSAP)

Question 27

a router in a normal area that does not connect to another area (red)

Answer 27

level 1

Question 28

a backbone router that does not connect to other areas (green)

Answer 28

level 2

Question 29

a router in a normal or backbone area that connects different areas (blue)

Answer 29

level 1-2