Network Routing: Basics and FoundationsFatima
SadiqInternshipObjectives:Genera viewO! NetworkingBroad view o! how
addressing and routing are tied together "ow di#erent architectura
components are reated to routing$%ampeSending&ost 'ard in rea
i!eneeds:(inima In!ormation incuding &erson Name house ) *
street no *'it+ name and 'ountr+ Name,- .o short the address we w/
need the !oowing components:&osta 'odeStreet 0ddress"ouse
)0ddressing and Internet Service:Network routing re!ers to the
abiit+ o! an eectronic communication network to send a unit o!
in!ormation !rom point 0 to point B b+ determining a path through
the network* and b+ doing so e1cient+ and quick+,Internet protoco
2I& 0ddressing3 : It consist o!two parts-Netid 2&osta
code3"ostid 2house 0ddress3.'& 2transmission contro
&rotoco3.he Internet/s conceptua !ramework* known as TCP/IP
2Transmission Control Protocol/Internet Protocol3* reies on a
deiver+ mode in which .'& is in charge o! the reiabe deiver+ o!
in!ormation* whie I& is in charge o! routing* using the I&
addressing mechanism, I&* however*does not worr+ about whether
the in!ormation is reiab+ deivered to the address or is ost during
transit,4i#erence Between Internet and &osta S+stem:0 ke+
di#erence in the Internet as opposed to the posta s+stem is that
the sending host 5rst sends a beacon to the destination address
2host3 to see i! it is reachabe* and waits !or an acknowedgment
before sending the actua message, Since the beacon aso uses the
same transmission mechanism* i,e,* I&* it is possibe that it
ma+ not reach the destination,.hen timer use,Network Routing:6hen
packet move !rom source to destination the+ ma+ traverse !rom some
cross points these cross points are caed Router,0 router/s
!unctions are to read the destination address marked in an incoming
I& packet* to consut its interna in!ormation to identi!+ an
outgoing ink to which the packet is to be !orwarded* and then to
!orward the packet ,$1cient4eiver o! &acket:For e1cient deiver+
o! packets* there are severa ke+ !actors to consider:273 routers
with a reasonabe amount o! bu#er space 283 inks with adequate
bandwidth293 actua transmission with minima error 2to minimi:e
packets being garbed32;3 the routers/e1cienc+ in switching a packet
to the appropriate outgoing ink,I& 0ddressing:I! one has to
send data to an+ host in the Internet* there is a need to unique+
identi!+ a the hosts in the Internet, .hus* there is a need !or a
goba addressing scheme in which no two hosts have the same address,
Goba uniqueness is the 5rst propert+ that shoud be provided in an
addressing scheme,'ass!u 0ddressing Scheme:0n I& address
assigned to a host is 98 bits ong and shoud be unique, .his
addressing* known as I&v; addressing,.he I& address space
was origina+ divided into three di#erent casses* 'ass 0* 'assB* and
'ass ',For readabiit+* I& addresses are e%pressed as !our
decima numbers* with a dot between them, .his !ormat is caed the
dotted decimal notation, -.he notation divides the 98>,-.he
origina rationae behind casses o! di#erent si:es was to provide the
Be%ibiit+ to support di#erent si:ed networks* with each network
containing a di#erent number o! hosts, .hus* the tota address ength
can sti be kept 5%ed at 98 bits* an advantage !rom the point o!
view o! e1cient address processing at a router or a host, 0sSub
nettingCNetmask:0 subnet or sub
