Download Static Routing Protocols - IT246

Prof. Alfred J Bird, Ph.D., NBCT
http://www.cs.umb.edu/~abird
[email protected]
Office – McCormick 3rd floor 607
Office Hours – Monday 3:00 to 4:00 and Thursday 4:00PM to 5:30
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A router decides where to sent the packet next
Works at layer 2 (Data Link)
Routing Tables
Routing Rules (How does it decide?)
Routers are often set up in a mesh topology
Gateway Address
Network Segments
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What is a Routing Protocol
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Routing Protocols provide a standardized format for
route management including route selection, sharing
route status with neighboring routers and
calculating alternative routes if the best path route is
down.
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There are basically two types of routing
protocols
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Static protocols
Dynamic Protocols
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Static Route
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A static route is list of IP addresses to which data
traffic can be forwarded and has been entered
manually into either a router’s or a computer’s
routing table.
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Variable Length Subnet Masking
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Routes can be configured using different length
subnet masks
Look at the previous example
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The 10.10.200.0 subnet only needs four (4) IP
addresses, so why would we want to use more.
What are the four (4) needed IP addresses?
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What is the path from A1 on LAN A to B1 on
LAN B?
A1 LAN A – 10.10.20.1
 FA0/0 on ROUTER A – 10.10.20.250
 FA0/1 on Router A – 10.10.200.1
 FA0/2 on Router B – 10.10.200.2
 FA0/0 on Router B – 10.10.10.250
 B1 on LAN B – 10.10.10.1
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So we must program this information
manually!
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What is the Gateway of Last Resort?
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The IP Address of the router in your network where
data packets with unknown routes should be
forwarded.
The purpose is to configure a route for data packets
the do not have a destination route configured in the
routing table.
ip route 0.0.0.0 0.0.0.0
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There are two basic classes of Dynamic Routing
Protocols:
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Distance Vector Protocol
Link State Protocols
There are also hybrid protocols
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These are a combination of the two basic protocols
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The primary features of a dynamic routing
protocol are:
What information is exchanged between routers.
 When updated routing information is exchanged.
 Steps for reacting to changes in the network.
 Criteria for establishing the best route selection.
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Path Determination
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Metric
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A numeric measure assigned to routes
Convergence
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Procedure to determine best route
Time it takes for the router to obtain a clear view of
the routes
Load Balancing
 Allowing the router to use multiple data paths
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Hop Count
Reliability
Bandwidth
Delay
Cost
Load
Ticks
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A distance Vector Protocol periodically sends it
routing table to its neighbors or adjacent
routers.
When the neighboring router receives a table, it
assigns a distance vector to each route.
The distance vector is typically specified by
some metric such as hop count.
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RIP
Created in 1988
 Uses hop count
 Maximum number of hops is 15
 Exchanges tables every 30 seconds
 Can consume a lot of bandwidth
 Slow convergence
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A Link State Protocol establishes a relationship
with neighboring routers and uses route
advertisements to build a routing table.
Key Issues:
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Finds neighbors/adjacencies
Uses route advertisements to build routing tables
Sends “Hello” packets
Send updates when routing changes.
Also called Shortest Path First Protocols
Based upon the work of E. W. Dijkstra
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OSPF (Open Shortest Path First)
Developed by the IGP (Interior Gateway Protocol)
working group of the IETF (Internet Engineering
Task Force)
 It is an open (non-proprietary) protocol
 Supported by many vendors
 Has rapid convergence
 It consumes very little bandwidth
 Difficult to configure
 Uses VLSM
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IS-IS (Intermediate System to Intermediate System)
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Very similar to OSPF
Designed as part of the OSI network layer service
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EIGRP (Enhanced Interior Gateway Routing
Protocol)
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A Cisco proprietary protocol.
Combines both distance vector and link state
algorithm.
An enhanced version of the IGRP protocol
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Load the CD Software.
Go to page 368, section 9-2 in the textbook
Follow along with the activity.
Go to page 387, section 9-7 in the textbook.
Follow along with the activity.
Record all the results from your actions.
Submit a report when you have completed the
activity.