A computer network or data network is a telecommunications network that allows computers to exchange data.

ADVANTAGES

•Connectivity•Sharing•Updates•Information

PROBLEMS WITH THIS NETWORK

•Concession Control•Sender And Destination•Speed degradation•Security•If One Route is Destroyed•Efficiency

ENHANCED INTERIOR GATEWAY ROUTING PROTOCOL (EIGRP)

(The protocol was designed by Cisco Systems as a proprietary protocol, available only on Cisco routers, but Cisco converted it to an open standard in 2013.)

SecurityCongestion Handling AlgorithmEfficiencyBest Routing Finding LogicMinimal DatabaseDual algorithmSupports IPv4 IPv6 etcAnother Root Finding Logic(loop free)

It is the process of selecting best paths in a network. Routing is performed for All Kind Of Networks.

TECHNICALY: It is the process of determining, selecting the best outgoing path that a packet has to take in a Network.

Ex: What Player Do in Football Game?

TWO TYPES OF ROUTINGS ARE•Static (Non Adaptive)•Dynamic(Adaptive)

non-adaptive routing networks may use manually

configured routing tables. suitable on small networks public switched telephone

network (PSTN).

adaptive routing constructing routing tables

automatically Small+Large Networks RIP , OFPS , ISIS , BGP

etc.

A routing protocol is a set of processes, algorithms, and messages that are used to exchange routing information

PURPOSE•Discovery of remote networks•Maintaining up-to-date routing information•Choosing the best path to destination networks•Ability to find a new best path if the current path is no longer available

•Interior Routing Protocols•Used within an autonomous system•Used within an area of administrative control

•Exterior Routing Protocols•Used between autonomous systems•Used to peer with networks in which you have no administrative control

Ethernet

Router

Ethernet

Ethernet

RouterRouter

Ethernet

Ethernet

EthernetRouterRouter

Router

AutonomousSystem 2

AutonomousSystem 1

RIPv1: • (RIP version 1) defined in RFC 1058.• There is no support for VLSM (variable length subnet masks)•There is also no support for authentication.

RIPv2: • (RIP version 2) is defined in RFC 2453. •There is support for authentication.• It uses hop count as routing metric with that it is also slow to converge• Not very scalable. • Still it is limited to 15 hops only.

RIPng:• (RIP next generation), defined in RFC 2080. •It has support of IPv6.

•shortest paths from a single source vertex. •It is slower than Dijkstra's algorithm•More versatile, as edge weights are negative numbers.

•Invented by Cisco to overcome limitations of RIP•Allows for hop count up to 255•Allows for multiple route METRICS

1. Bandwidth2. Delay3. Load4. MTU5. Reliability

•Classful, no support for VLSM

A metric is a variable assigned to routes as a means of ranking them from best to Worst

•Hop Count: Simply counts router hops•Bandwidth: Choose a higher-bandwidth path over a lower-bandwidth.•Delay: Delay is a measure of the time a packet takes to traverse a route•Cost: It is determined by the preferable route.•Reliability: Reliability measures the likelihood that the link will fail in some way and can be either variable or fixed.

•VERSION: RFC 2328(OSPFv2), 1998.•USES: Dijkstras Algorithm•DRAWBACK: Designing can be complicated•SUPPORTS:

1. Internet Protocol Version 4 (IPv4)2. Internet Protocol Version 6 (IPv6) 3. Variable Length subnet masking (VLSM)4. Classless Inter-Domain RouTing(CIDR).

•METRICS1. Intra-area2. Inter-area3. External Type 14. External Type 2

VERSION: RFC 1142, 1990USES: Dijkstra Algorithm•Mainly used by large service providers•Does not use IP to carry routing information•Classless, supports VLSM

• With distance vector routing, each node has information only about the next hop:

• Node A: to reach F go to B• Node B: to reach F go to D• Node D: to reach F go to E• Node E: go directly to F

• Distance vector routing makespoor routing decisions if directions are not completelycorrect (e.g., because a node is down).

• If parts of the directions incorrect, the routing may be incorrect until the routing algorithms has re-converged.

20

AA BB CC

DD EE FF

•IF One Node Gets DownThen Whole Network Shuts Down

•LINK-STATE = OSPF + ISIS•ONLY 5 STEPS

1.Determining The Neighbors Of Each Node (HELLO)2.Determine the cost of each path (ECHO)3.Flooding ALGORITHM4.Creating The Map And Tables5.Calculating The Shortest Paths AA BB CC

DD EE FF

◦ Relationship (“adjacency”) with neighbors◦ Generates link state advertisements

LSA = (Link Id, State Of The Link, Cost, Neighbors Of The Link)

◦ Topological database and link state database.

23

• Each node has a complete map of the topology.• If a node fails, each node can calculate the new route.• DIFFICULTY: All nodes need to have a consistent view of the

network.

24

AA BB CC

DD EE FF

A B C

D E F

A B C

D E F

A B C

D E F

A B C

D E F

A B C

D E F

A B C

D E F

EIGRP = The concepts of ( RIP + IGRP + OSOS + ISIS+ Distance Vector + Link State + New Concepts)

A HYBRID NETWORK…!!!

• BANDWIDTH: Minimum Bandwidth (in kilobits per second) along the path from router to destination network.

• LOAD: Number in range 1 to 255; 255 being saturated.• TOTAL DELAY: Delay, in 10s of microseconds, along the path

from router to destination network.• RELIABILITY: Number in range 1 to 255; 255 being the most

reliable.• MTU: Minimum path Maximum Transmission Unit (MTU) (never

used in the metric calculation).

• HOP COUNT: by default it is set to 100 and can be changed to any value between 1 and 255.

• SUCCESSOR :The best, least cost route to the destination installed in the routing table; multiple successors can be installed for load balancing

• FEASIBLE SUCCESSOR: A next-hop alternative route to the destination kept in the topology table, ready to be installed if the successor fails; feasible successors are only in the topology table

• ACTIVE STATE: EIGRP is still trying to calculate the best path for the specific route

• PASSIVE STATE: that EIGRP has determined the path for the specific route and has finished processing

1. Like OSPF, EIGRP maintains three unique tables to assist in routing traffic.•Neighbor Table•Topology Table•Routing Table

2. EIGRP maintains one table of each for each routed protocol configured on the router.

•3 Neighbor Tables•3 Topology Tables•3 Routing Tables

• Use the command

show ip eigrp neighbors

• Similar to OSPF’s Adjacencies database:1. Contains a list of all neighbors discovered through

hellos2. Maintains hello and holdtime intervals on each

neighborRouter#show ip eigrp neighbors

IP-EIGRP neighbors for process 100H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num0 192.168.224.2 Se0 13 00:01:28 930 5000 0 301 192.168.208.2 Se1 11 00:02:20 35 1140 0 21

Router#show ip eigrp topology

IP-EIGRP Topology Table for process 100Codes: P – Passive, A – Active, U – Update, Q – Query, R – Reply, r – Reply statusP 192.150.42.120 255.255.255.248, 1 successors, FD is 2172416 via 192.150.42.9 (2172416/2169856), Fddi0P 192.150.42.8 255.255.255.248, 1 successors, FD is 28160 via Connected, Fddi0

Feasible Distance

Reported Distance

• Use the command to view the table

show ip eigrp topology

• Similar to LINK-STATE database:Contains all routes the router has learned about from its neighbors and all the information necessary to calculate a set of distances and vectors to all reachable destinations

1. FD—Feasible Distance: lowest calculated metric to reach a destination as opposed to.

2. RD—Reported Distance: distance to the destination reported by the neighbor.

• Use the command to view table

show ip route

• Like ALL ROUTING protocols: EIGRP maintains a routing table with best routes to destination networks

REPORTED DISTANCE:Destination: Router A •via D: RD(4) •via C: RD(3)The route via C have lowest cost.

FEASIBLE DISTANCE:Destination: Router A•via D: RD(4), FD(5)•via C: RD(3), FD(6)

DUAL therefore finds that:Destination: Router A•via D: RD(4), FD(5) successor•via C: RD(3), FD(6) feasible successor

It supports classless interdomain routing (CIDR) and variable-length subnet masks (VLSM).

It sends routing updates only when network topology changes instead of its entire routing table at regular intervals.

It is less CPU intensive.

It supports IPX and AppleTalk. OSPF supports only IP.

EIGRP supports unequal-cost load balancing.

OSPF propagates network changes to all routers in an area. EIGRP has much better convergence time than OSPF/ISIS.

Loop control that Distance vector / Link State Doesn’t have.

• Dynamic Routers are worldwide by nearly every organization or individual which uses internet. Following are the network hardware vendors that make these algorithms practically possible in real life.

i. CISCO Systems (uses EIGRP)ii. D- Linkiii. Delliv. Juniper Networksv. Huaweivi. Telco Systemvii. HP• Upcoming The Darkest Algorithm by convergEX group.(rumors)

 IT IS CISCO PROPRIETARY If you are working in a mixed environment, thenit does not interoperate with other vendors' devices.

IN A POORLY DESIGNED NETWORK:One malfunctioning router can trigger bad router problem much better.A chain reaction that brings an entire network down

ISIS-OFPS handles the Situation However, if EIGRP is properly designed, this problem can be overcome.

[1].Wikipedia. “Routing” http://en.m.wikipedia.org/wiki/Router_(computing). October 2014.

[2]. Sumitha J. “Routing Algorithms in Networks” Research Journal of Recent Sciences Vol.3(ISC-2013), 1-3. February 2014.

[3]. B, Richard . "On a routing problem". Quarterly of Applied Mathematics 16: 87–90.

[4]. CISCO. “Enhanced Interior Gateway Routing Protocol” http://www.cisco.com/c/en/us/support/docs/ip/ Interior Gateway Routing Protocol-eigrp/16406-eigrp-toc.html. 2014

[5]. Wikipedia. “Adaptive Routing” http://en.m.wikipedia.org/wiki/Adaptive_routing. October 2014.