TCP/IP Protocol Suite 1 Upon completion you will be able to: Unicast Routing Protocols: Unicast Routing Protocols: RIP, OSPF, and BGP RIP, OSPF, and BGP • Distinguish between intra and interdomain routing • Understand distance vector routing and RIP • Understand link state routing and OSPF • Understand path vector routing and BGP Objectives
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
TCP/IP Protocol Suite 1
Upon completion you will be able to:
Unicast Routing Protocols:Unicast Routing Protocols:RIP, OSPF, and BGPRIP, OSPF, and BGP
• Distinguish between intra and interdomain routing• Understand distance vector routing and RIP• Understand link state routing and OSPF• Understand path vector routing and BGP
Objectives
TCP/IP Protocol Suite 2
14.1 INTRA- AND INTERDOMAIN ROUTING
Routing inside an autonomous system is referred to as intradomain Routing inside an autonomous system is referred to as intradomain routing. Routing between autonomous systems is referred to as routing. Routing between autonomous systems is referred to as interdomain routing. interdomain routing.
TCP/IP Protocol Suite 3
Figure 14.1 Autonomous systems
TCP/IP Protocol Suite 4
Figure 14.2 Popular routing protocols
TCP/IP Protocol Suite 5
14.2 DISTANCE VECTOR ROUTING
In distance vector routing, the least cost route between any two nodes is In distance vector routing, the least cost route between any two nodes is the route with minimum distance. In this protocol each node maintains a the route with minimum distance. In this protocol each node maintains a vector (table) of minimum distances to every nodevector (table) of minimum distances to every node
The topics discussed in this section include:The topics discussed in this section include:
Initialization Initialization Sharing Sharing Updating Updating When to Share When to Share Two-Node Loop Instability Two-Node Loop Instability Three-Node Instability Three-Node Instability
TCP/IP Protocol Suite 6
Figure 14.3 Distance vector routing tables
TCP/IP Protocol Suite 7
Figure 14.4 Initialization of tables in distance vector routing
TCP/IP Protocol Suite 8
In distance vector routing, each node shares its routing table with its
immediate neighbors periodically and when there is a change.
Note:Note:
TCP/IP Protocol Suite 9
Figure 14.5 Updating in distance vector routing
TCP/IP Protocol Suite 10
Figure 14.6 Two-node instability
TCP/IP Protocol Suite 11
Figure 14.7 Three-node instability
TCP/IP Protocol Suite 12
14.3 RIP
The Routing Information Protocol (RIP) is an intradomain routing The Routing Information Protocol (RIP) is an intradomain routing protocol used inside an autonomous system. It is a very simple protocol protocol used inside an autonomous system. It is a very simple protocol based on distance vector routing. based on distance vector routing.
• The destination in a routing table is a network, which means the first
column defines a network address.
• The metric used by RIP is very simple; the distance is defined as the
number of links (networks) to reach the destination. For this reason, the
metric in RIP is called a hop count.
• Infinity is defined as 16, which means that any route in an autonomous
system using RIP cannot have more than 15 hops.
• The next-node column defines the address of the router to which the packet
is to be sent to reach its destination.
TCP/IP Protocol Suite 13
Figure 14.8 Example of a domain using RIP
TCP/IP Protocol Suite 14
14.4 LINK STATE ROUTING
In link state routing, if each node in the domain has the entire topology In link state routing, if each node in the domain has the entire topology of the domain, the node can use Dijkstra’s algorithm to build a routing of the domain, the node can use Dijkstra’s algorithm to build a routing table.table.
The topics discussed in this section include:The topics discussed in this section include:
Building Routing Tables Building Routing Tables
TCP/IP Protocol Suite 15
Figure 14.15 Concept of link state routing
TCP/IP Protocol Suite 16
Figure 14.16 Link state knowledge
TCP/IP Protocol Suite 17
Building Routing Tables
FOUR ACTIONS TO BE PERFORMED FOR CREATING A ROUTING TABLE
Creation of Link State Packet(LSP)
Flooding of LSPs
Formation of Shortest path Trees: Dijkstra Algorithm
Calculation of Routing Table
TCP/IP Protocol Suite 18
Figure 14.17 Dijkstra algorithm
TCP/IP Protocol Suite 19
Figure 14.18 Example of formation of shortest path tree
TCP/IP Protocol Suite 20
Table 14.1 Table 14.1 Routing table for node ARouting table for node A
TCP/IP Protocol Suite 21
14.5 OSPF
The Open Shortest Path First (OSPF) protocol is an intradomain The Open Shortest Path First (OSPF) protocol is an intradomain routing protocol based on link state routing. Its domain is also an routing protocol based on link state routing. Its domain is also an autonomous system. autonomous system.
Divided into areas-A collection of networks, hosts, routers.
Special Routers-Area Border Routers at the borders.
Special Areas- Backbone with Backbone routers.
TCP/IP Protocol Suite 22
Figure 14.19 Areas in an autonomous system
TCP/IP Protocol Suite 23
Figure 14.20 Types of links
TCP/IP Protocol Suite 24
Figure 14.21 Point-to-point link
TCP/IP Protocol Suite 25
Figure 14.22 Transient link
TCP/IP Protocol Suite 26
Figure 14.23 Stub link
TCP/IP Protocol Suite 27
14.6 PATH VECTOR ROUTING
Path vector routing is similar to distance vector routing. There is at least Path vector routing is similar to distance vector routing. There is at least one node, called the speaker node, in each AS that creates a routing one node, called the speaker node, in each AS that creates a routing table and advertises it to speaker nodes in the neighboring ASs.. table and advertises it to speaker nodes in the neighboring ASs..
The topics discussed in this section include:The topics discussed in this section include:
Figure 14.48 Initial routing tables in path vector routing
TCP/IP Protocol Suite 29
Figure 14.49 Stabilized tables for four autonomous systems
TCP/IP Protocol Suite 30
14.7 BGP
Border Gateway Protocol (BGP) is an interdomain routing protocol Border Gateway Protocol (BGP) is an interdomain routing protocol using path vector routing. It first appeared in 1989 and has gone using path vector routing. It first appeared in 1989 and has gone through four versions. through four versions.