Network Layer

Front 1

What mechanism that differentiate between hosts and network?

Back 1

IP addressing

Front 2

What mechanism help hosts locate each other?

Back 2

DNS server

Front 3

What is a gateway?

Back 3

Is router which route packets to destination hosts.

Front 4

What is a default route

Back 4

Tell router where to forward traffic in case there's no route found for a destination.

Front 5

If there is multiple route what does routers use to forward packets?

Back 5

* hop count

* Bandwidth

* Metric

* Prefix length

* Delay

Front 6

What is unicast Routing?

Back 6

Is a unicast traffic with a specific destination ip address, simplest form of routing

Front 7

What technique routers use to detect and discard duplicates?

Back 7

Reverse path forwarding

Front 8

What is the difference between broadcast Routing and Multicast Routing?

Back 8

Broadcast flood all nodes , multicast flood nodes who wants the traffic

Front 9

What mechanism does Multicast use to prevent looping.

Back 9

STP

Front 10

What is anycast Routing?

Back 10

Where multiple destination hosthave same logical address. Packets sent to nearest Host

Front 11

What metric do distance vector routing use to decide routes?

Back 11

Hop count,route with less hop

Front 12

What is the difference between unicast routing and Multicast Routing?

Back 12

Unicast use graphs , Multicast use trees

Front 13

What are some Multicast protocol?

Back 13

DVMRP: Distance vector multicast routing protocol

MOSPF: Multicas open shortest path first

CBT: Core based tree

PIM: Protocol Independent Multicast

Front 14

What foes link state protocol use to make routing decisions?

Back 14

States of links of all routers

Front 15

What is the two Types of PIM(Protocol Independent Multicast)

Back 15

* PIM Dense Mode: used in LAN and use source based trees

* PIM Sparse Mode: use share trees, use in WAN

Front 16

What are the types of Routing Algorithm?

Back 16

*Flooding: flood packets to all int but to int it was received. create duplicates, TTL (time to live) is used to avoid loops.

* Selective flooding : flood only selected interface

* Shortest path: based on source & destination cost, calculate minimum number of hops

Front 17

What are some shortest path algorithms?

Back 17

* Dijkstra's algorithm

* Bellman ford algorithm

* Floyd warshall algorithm

Front 18

What do you call routing between two network?

Back 18

Internetworking

Front 19

What is an IGP

Back 19

Interior gateway protocol: is a routing protocols use within an organization or administration. Ex: RIP - OSPF

Front 20

What is an EGP

Back 20

Exterior gateway protocol: routing protocol between different organizations .

Front 21

What is tunnelling?

Back 21

Mechanism which allows two or more of the same network to communicate .

Front 22

What is the maximum transmission unit (MTU) Ethernet segment is set to?

Back 22

1500 bytes

Front 23

What is packet fragmentation

Back 23

Is packets that are too big for the 1500 bytes MTU set so it broken in smaller piece.

Front 24

What happen to DF(don't fragment) packets if its too big

Back 24

It is dropped

Front 25

How does routers know a packet is fragmented?

Back 25

Its MF(More Fragment) is set to 1

Front 26

What happened when packets are fragmented too small?

Back 26

The overhead increased

Front 27

How does Cisco routers chose between routes with the same prefix.

Back 27

Administrative Distance

Front 28

list of Administrative Distances:

Back 28

0 => Connected 1 => Static 20 => BGP (external routes) 90 => EIGRP (internal routes) 100 => IGRP 110 => OSPF115 => IS‐IS 120 => RIP 170 => EIGRP (external routes) 200 => BGP (internal routes) 254 => DHCP default route 255 => Unusable

Front 29

What does a lower metric indicate?

Back 29

Better route

Front 30

What is a Metric?

Back 30

Is the routing protocols internal measure of the route.

Front 31

What is gateway of yhe last resort?

Back 31

Route which is used if no entry exist in the routing table.