Transcript Slide 1

Net-Centric Computing Division
Department of Computer Science
Bogor Agricultural University
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KOM 312
KOMUNIKASI DATA
DAN JARINGAN KOMPUTER
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Internet Routing
Sri Wahjuni
my_juni04(at)ipb.ac.id
AGENDA
 Internet
Routing Protocol
Basic Routing
 Routing Information Protocol (RIP)
 Open Shortest Path First (OSPF)
 Border Gateway Protocol (BGP)

 Mobile
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 Multicast
Routing
IP
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ROUTING AND FORWARDING
 Routing
How to determine the routing table
entries
- carried out by routing daemon
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
 Forwarding
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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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ROUTING TABLE ENTRIES
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Destination IP Address:
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IP address of
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complete host address or network address
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?
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Network interface on which to send packet
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FORWARDING PROCEDURE
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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AUTONOMOUS SYSTEMS
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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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INTER AND INTRA DOMAIN ROUTING
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
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IGP
R
EGP
IGP
R
R
R
R
R
AS A
AS C
R
R
IGP
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AS B
AGENDA
 Internet
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Routing Protocol
 Multicast Routing
 Mobile IP
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MULTICASTING
G1
G1
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2
3
1
1
S
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2
5
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2
4
3
2
3
1 8
1 1 3
3
4
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2 4
7 2
G1
G1
5 4
2
1 2
3
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3
4
1
G3
2
3
1
6 3
4
G2
G3
Source S sends packets to multicast group G1
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MULTICAST ROUTING
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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REVERSE-PATH BROADCASTING
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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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INTERNET GROUP MANAGEMENT
PROTOCOL (IGMP)
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Internet Group Management Protocol:
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Each multicast router periodically sends an IGMP
query message to check whether there are hosts
belonging to multicast groups
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Host can join a multicast group by sending an IGMP
message to its router
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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REVERSE-PATH MULTICASTING
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DISTANCE-VECTOR MULTICAST ROUTING
PROTOCOL (DVMRP)
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Based on combination of RIP and RPM
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AGENDA
 Internet
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Routing Protocol
 Multicast Routing
 Mobile IP
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ROUTING IN MOBILE IP
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When an MH moves to foreign network, the MH
obtained CA (care-of address) from foreign agent
(FA)
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ROUTING OPTIMIZATION
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2b : binding message to save by CH in its binding
cache
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GROUP ASSIGNMENT
RIP
 OSPF
 DHCP
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REFERENCES
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Garcia A.L., Widjaja A. 2004. Networks
Communication : Fundamental Concepts and Key
Architectures 2nd ed. – Chapter 8. McGraw-Hill
Companies, Inc.
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