1. 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 1 swj/12

2. AGENDA Internet Routing Protocol Basic Routing Routing Information Protocol (RIP) Open Shortest Path First (OSPF) Border Gateway Protocol (BGP) Multicast Routing Mobile IP 2 swj/12

3. 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 3 swj/12

4. 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 4 swj/12

5. 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 5 swj/12

6. 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 6 swj/12

7. 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 EGPIGP 7 swj/12

8. AGENDA Internet Routing Protocol Multicast Routing Mobile IP 8 swj/12

9. MULTICASTING Source S sends packets to multicast group G1 S 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 9 swj/12

10. 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 10 swj/12

11. 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 11 swj/12

12. 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 12 swj/12

13. R EVERSE -P ATH M ULTICASTING 13 swj/12

14. D ISTANCE -V ECTOR M ULTICAST R OUTING P ROTOCOL (DVMRP) Based on combination of RIP and RPM 14 swj/12

15. AGENDA Internet Routing Protocol Multicast Routing Mobile IP 15 swj/12

16. R OUTING IN M OBILE IP When an MH moves to foreign network, the MH obtained CA (care-of address) from foreign agent (FA) 16 swj/12

17. R OUTING OPTIMIZATION 2b : binding message to save by CH in its binding cache 17 swj/12

18. G ROUP ASSIGNMENT RIP OSPF DHCP 18 swj/12

19. REFERENCES Garcia A.L., Widjaja A. 2004. Networks Communication : Fundamental Concepts and Key Architectures 2 nd ed. – Chapter 8. McGraw-Hill Companies, Inc. swj/11 19