TRANSPORT LAYER BY, Parthasarathy.g

Overview of Transport Layer Make communication among applications running on different hosts. Sender Side: breaks applications messages into segments Receiver Side: Reassemble segments into messages passes to application layer.

Network graph: Forward’s packet lowest cost path. Can calculate shortest path and load them into non volatile storage. PROBLEMS: 1.Does not deal with node or link failure. 2.Does not consider addition of new nodes or link. SOLUTION: Distance vector routing algorithm. Link state algorithm.

DV algorithm: (bellman ford algorithm) Router sends its table to its neighbour for every t seconds It updates the table based on new informations. COUNT TO INFINITY: when the number of hops counts more than one it is said to be count to infinity. DV algorithm: (bellman ford algorithm)

RIP- ROUTING INFORMATION PROTOCOL SPLIT HORIZON TECHNIQUE: achieved by poison reverse. prevent loop in routing. information about the routing for a particular packet is not sent in same direction. RIP- ROUTING INFORMATION PROTOCOL Straight forward implementation of distance vector routing. Sends an update message for every updates .

RIP V2 packet format Command version must be zero family on net 1 route taps Address prefix of net1 Mask of net1 Distance of net1 family of net2 route taps Address prefix of net2 Mask of net2 Distance of net2

LINK STATE ROUTING: Send to all nodes information about directly connected links . LINK STATE PACKET (LSP) ID of the node. Cost of link to each directly connected nodes. Sequence number. Time to live (TTL). RELIABLE FLOODING : Stores , forwards, generates the LSP. Sequence no= 0 , when reboot.

GLOBAL INTERNET PROTOCOL : NSF NET BACKBONE BARNET REGIONAL WESTSIDE MIDNET NACR LA STANFORD BERKLEY UNIV FS

BACKBONE SERVICE PROVIDER LARGE CORPORATION BACKBONE SERVICE PROVIDER CONSUMER ISP PEERING POINT CONSUMER ISP SMALL CORPORATION

AUTONOMOUS SYSTEM ( ROUTING DOMAIN) Corresponds to an administrative domain. Eg. University, company etc…. NETWORK WITH 2 AUTONOMOUS SYSTEM: R1 R3 R5 R6 R2 R4

INTER DOMAIN ROUTING PROTOCOLS: EGP- EXTERIOR GATEWAY PROTOCOL. BGP- BORDER GATEWAY PROTOCOL. BGP: It is a collection of set of ASS. internet consist of connection of multiple backbone networks called service providers. service provider may be private or government . backbone backbone providers small providers companies large companies ISP consumers

BGP4: it defines local traffic as traffic that originates at (or) terminates on nodes within autonomous system. Transit traffic – traffic passing through AS. Types of AS : Stub AS Multihomed AS Transit AS

Stud AS: single connection to one other AS. carry only local traffic Stud AS: single connection to one other AS. carry only local traffic. eg- small cooperation. Multihomed AS: connected with more than one other AS. refuses to carry transit traffic. eg- large corporations. Transit AS: it has more connection and designed carry both transit and local traffic. (backbone)

AS : BGP issues: it has speaker . Has one or more border gateways which are routers. Through routers packets leaves AS. It advertises complete path with list of autonomous system to reach a particular network. BGP issues: AS number should be unique. AS number are 16 bits number assigned ny a central authority.

Internet Protocol Version 6 (IPV6) 128 bits It is a next generation IP. Supports real time service. Supports multicast. Supports authentication and security mechanism. Supports auto configuration. Enhance routing functionality including support for mobile host. Address notation X:X:X:X:X:X:X:X

IPv6 header Version Traffic Flow label Source address Payload length Next header HOP Source address Destination address Header data

Internet Multicast: one to many multicast. One to many multicast: Source specific multicast(SSM) : A receiving host specifies both a multicast group and sending host. Many to many multicast (ASM): A host signal decides to join or leave a group by communicating with its local route using special protocol.

IPv4 IGMP ( Internet Group Management Protocol) IPv6 MLD ( Multicast Listener Dictionary) TYPES: Distance vector Multicast Routing Protocol: router already knows the shortest path through the source n goes to router n. it eliminates broadcast packets by parent for LAN (relative to S) forward Shortest path to S (leave via DV) Smallest address to break ties.

Network layer : IGMP ICMP IP ARP each multicast router needs to know the list of groups that have atleast one loyal member related to each interface Collection of this time of information is alone at two levels . Locally  IGMP Globally  DVMRP , PIM

Common multicast protocol: protocols Source group Based based MOSPF DVMRP DM SM CBT DIM DVMRP- an interior gateway protocol. only rout multicast datagrams. IGMP – used for discovery of host in multicast group. DVMRP routs multicast datagram within an AS

This is portion of packet DVMRP – Packet Type – indicates it is a DVMRP packet. Code – indicates the type of DVM of the packet code Checksum – to detect error. Minor and major versions – indicates the current version of DVMRP. Minor = 0XFF Major = 3 Type Code Checksum Reserved Minor version Major Version (0xFF) ( 3 ) This is portion of packet

PIM – Protocol Independent Multicast 0 31 PIM- DM ( dense multicast ) Implicitly built’s shortest path tree by flooding multicast traffic domain. PIM-SM (sparse multicast ) Explicitly built’s shortest path tree to a route for group and creates shortest path tree . Version =2 Type Reserved Checksum message type