unicast routing protocols
DESCRIPTION
Computer NetworksTRANSCRIPT
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 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
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In distance vector routing, each node shares its routing table with its
immediate neighbors periodically and when there is a change.
Note:Note:
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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 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
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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
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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.
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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:
Initialization Initialization Sharing Sharing Updating Updating
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.