Net-Centric Computing Division Department of Computer Science Bogor Agricultural University

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29 Οκτ 2013 (πριν από 3 χρόνια και 9 μήνες)

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Net
-
Centric Computing Division
Department of Computer Science

Bogor Agricultural University





KOM 312

K
OMUNIKASI

D
ATA


DAN

J
ARINGAN

K
OMPUTER


Internet Routing

Sri
Wahjuni

my_juni04(at)ipb.ac.id

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AGENDA


Internet Routing Protocol


Basic Routing


Routing Information Protocol (RIP)


Open Shortest Path First (OSPF)


Border Gateway Protocol (BGP)


Multicast Routing


Mobile IP

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R
OUTING

AND

F
ORWARDING


Routing


How to determine the routing table
entries

-

carried out by routing daemon



Forwarding


Look up routing table & forward packet
from input to output port


-

carried out by IP layer


Routers exchange information using
routing protocols to develop the
routing tables

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R
OUTING

T
ABLE

E
NTRIES


Destination IP Address:


complete host address or network address


IP address of


next
-
hop router or directly connected network


Flags


Is destination IP address a net address or host
address?


Is next hop, a router or directly connected?


Network interface on which to send packet


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F
ORWARDING

P
ROCEDURE


Does routing table have entry that matches
complete destination IP address? If so, use this
entry to forward


Else, does routing table have entry that matches
the longest prefix of the destination IP address?
If so, use this entry to forward


Else, does the routing table have a default entry?
If so, use this entry.


Else, packet is undeliverable


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A
UTONOMOUS

S
YSTEMS


Internet viewed as collection of autonomous systems


Autonomous system (AS)

is a set of routers or
networks administered by a single organization


Same routing protocol need not be run within the AS


But, to the outside world, an AS should present a
consistent picture of what ASs are reachable

through
it


Stub AS:

has only a single connection to the outside
world


Multi
-
homed AS:

has multiple connections to the
outside world, but refuses to carry transit traffic


Transit AS:

has multiple connections to the outside
world, and can carry transit and local traffic


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I
NTER

AND

I
NTRA

D
OMAIN

R
OUTING


Interior Gateway Protocol (IGP):
routing within AS



RIP, OSPF


Exterior Gateway Protocol (EGP):
routing between AS’s



BGPv4


Border Gateways
perform both IGP & EGP routing

R

R

R

R

R

R

R

R

AS A

AS B

AS C

IGP

EGP

IGP

IGP

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AGENDA


Internet Routing Protocol


Multicast Routing


Mobile IP

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MULTICASTING


Source
S

sends packets to multicast group G1

S

G1

G1

G1

G1

G3

1

2

3

4

5

6

7

8

1

2

3

4

5

1

2

3

4

1

2

3

4

5

1

2

3

1

2

3

1

2

1

2

3

4

1

2

3

4

G2

G3

3

4

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M
ULTICAST

R
OUTING


Multicast routing useful when a source wants to
transmit its packets to multiple

destinations
simultaneously


Relying on
unicast

routing by transmitting each
copy of packet separately works, but can be very
inefficient if number of destinations is large


Typical applications is multi
-
party conferencing
over the Internet


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R
EVERSE
-
P
ATH

B
ROADCASTING

While

a

router

received

a

multicast

packet
:


records

the

source

address

of

the

packet

and

the

port

the

packet

arrives

on


If

the

shortest

path

from

the

router

back

to

the

source

is

through

the

port

the

packet

arrived

on

(
parent

port
)

:


Forward

the

packet

to

all

port

except

the

one

the

packet

arrived

on


Otherwise

drop

the

packet


For bandwidth efficiency:
Truncated reverse
-
path
broadcasting

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I
NTERNET

G
ROUP

M
ANAGEMENT

P
ROTOCOL

(IGMP)


Internet Group Management Protocol:



Host can join a multicast group by sending an IGMP
message to its router


Each multicast router periodically sends an IGMP
query message to check whether there are hosts
belonging to multicast groups


Hosts respond with list of multicast groups they belong to


Hosts randomize response time; cancel response if other
hosts reply with same membership


Routers determine which multicast groups are
associated with a certain port


Routers only forward packets on ports that have
hosts belonging to the multicast group


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R
EVERSE
-
P
ATH

M
ULTICASTING

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D
ISTANCE
-
V
ECTOR

M
ULTICAST

R
OUTING

P
ROTOCOL

(DVMRP)


Based on combination of RIP and RPM

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AGENDA


Internet Routing Protocol


Multicast Routing


Mobile IP

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R
OUTING

IN

M
OBILE

IP


When an MH moves to foreign network, the MH
obtained CA (care
-
of address) from foreign agent
(FA)


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R
OUTING

OPTIMIZATION


2b : binding message to save by CH in its binding
cache

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G
ROUP

ASSIGNMENT


RIP


OSPF


DHCP

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REFERENCES


Garcia A.L.,
Widjaja

A. 2004. Networks
Communication :
Fundamental Concepts and Key
Architectures
2
nd

ed.


Chapter 8
.
McGraw
-
Hill
Companies, Inc.


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