Routing Protocols (RIP, OSPF, BGP)

CONTENTS INTRA-DOMAIN AND INTER-DOMAIN ROUTING RIP OSPF BGP

INTRA-DOMAIN AND INTER-DOMAIN ROUTING

Popular routing protocols Figure 13-1 Popular routing protocols Inter-domain Intra-domain

Figure 13-2 Autonomous systems

1. Distance Vector Routing

Figure 13-3 Example of updating a routing table

Initial routing tables in a small Figure 13-4 Initial routing tables in a small autonomous system

Final routing tables for the previous figure

Figure 13-12 Hop count

Instability

Solution for Instability 1. Defining Infinity 2. Split horizon

3. Split Horizon and Poison reverse “ Do not use this value; what I know about this route comes from you”

2. Link State Routing OSPF:(Open Shortest Path First)

Link State Routing:- Building Routing Tables 1. Creation of the states of the links by each node, called the Link state packet (LSP). :- node identity, list of links, sequence no and age 2. Flooding of LSP to every other router 3. Formation of a shortest path tree for each node. :- Dijkstra Algorithm 4. Calculation of a routing table based on the shortest path tree

Areas in an autonomous system Figure 13-18 Areas in an autonomous system

Types of links

Figure 13-20 Point-to-point link

Figure 13-21 Transient link

Figure 13-22 Stub link

Figure 13-23 Example of an internet

Graphical representation of an internet Figure 13-24 Graphical representation of an internet

Figure 13-26 Router link

3. Path Vector Routing BGP: (Border Gateway Protocol)

Initialization Sharing Updating Loop prevention Policy routing Optimum path

BGP: (Border Gateway Protocol) Types of autonomous 1. Stub AS :-data cannot pass through a stub AS :- Only one connection to another AS 2. Multi-homed AS :- More than one connection to other AS :- data cannot pass through a stub AS 3. Transit AS BCP Attribute:- Well Known Mandatory 2. Discretionary Optional Transitive 2. Non Transitive BGP Session

Congestion Control Data Traffic:- Traffic Descriptor Avg. Data Rate Peak Data Rate Max. Burst Size Traffic Profiles CBR ( Constant BR) VBR ( Variable BR) Bursty Data

Network Performance

Congestion Control Categories