Network pioneers Essay


Network innovators attempted to construct multi-protocol webs in the early 1990s were faced with a batch of jobs. Most of the protocols are running in endeavor web had no scalable routing protocols that enabled the web applied scientist to construct dependable big webs. The grown-up and established routing protocols like RIP ( Routing Information Protocol ) or IGRP ( Interior Gateway Routing Protocol ) were dependable, slow and the newer energetic routing protocol, like OSPF ( Open Shortest Path First ) were hard and non confirmed in the field at that clip. Cisco Systems decided to get the better of the spread between the bing engineerings with a latest routing protocol, named Enhanced Interior Gateway Routing Protocol ( EIGRP ) that combined the simpleness and dependability of the old routing protocols.

The intent of this undertaking is to look into stableness, public presentations in OSPF and EIGRP protocols with CISCO based big graduated table web. Network designers recommend mix protocols for big web. My effort is to turn out and happen alterations in OSPF and EIGRP constellations. This will assist us to make choose best constellation and it will avoid potentially expensive web outages.


Trying to accomplish following aims in CISCO based big graduated table web. This web contains OSPF, BGP and EIGRP protocols. The OPNET Technology is utilizing to make following things

  1. Examination nexus uses and routing way.
  2. Test web public presentation with aid of flow analysis.
  3. Visualize web to find overladen links.
  4. Deploy application and investigate impact on web.
  5. Identify web failover recovery by executing failure analysis.

History of CISCO System

Sandy Lerner and Len Bosack are married twosome and Richard Troiano worked together at Stanford University as a computing machine operation staff. They were founded Cisco Systems in 1984. Lerner started making full clip work to Cisco in 1987 at Schlumberger. The name “ Cisco ” was extracted from the metropolis name, San Francisco.

The Cisco System has stated sell routers back uping multiple web protocols. It was commercially success in that clip. They were the innovator in this engineering. The Internet Protocol ( IP ) became widely accepted, the importance of multi-protocol routing had refused. At present, Cisco ‘s largest routers, switches are chiefly used to present routing ( border, nucleus, and entree ) , IPTV, exchanging, security and web conferencing etc.

In March 2000, at the extremum of the dot-com bubble ( covering approximately 1998 to 2001 ) , Cisco was the most valuable and respectable company in the universe. They have market capitalisation of more than US $ 500 billion. Today ( In July 2009 ) , they are making a market capitalisation of about US $ 108.03 billion. It is still one of the most esteemed company in I.T industry. The CISCO was selected stock of the decennary on American Stock Exchange. The Cisco 7500 Series router was voted 3rd in the merchandise of the last decennary 1990-2000 after the Mosaic web browser and the Novell LAN director.

Today, Cisco Systems, Inc is a transnational corporation with more than 65,000 staff and one-year gross of more than US $ 36.10 billion as of 2009.

The Cisco systems vision is “ Changing the Way We Work, Live, Play and Learn ” . Cisco ‘s current mission is “ Welcome to the human web ” .


Today, Cisco System has large name in the web universe. They have of import hardware merchandises and package merchandises. Most of web designers, innovators, applied scientists recommend Cisco merchandises for their clients. Cisco covers all web sections such as routing, exchanging, radio LAN etc. This is the 1 and merely company covering all the web sectors and they have over 50 per centum market portion in all sections.

Cisco System has own routing protocols like EIGRP for their merchandises. These protocols do non back up to other engineerings but still they are leaders in the web industry.

Cisco ‘s market leading is the “ best kept secret ” in direction services. It has over 50 percent market leading across all divisions. Here is the market leading per centum wise

  • Storage Area Networks -20 Percent
  • Web conferencing – 45 Percentage
  • Routing Edge / Core / Access – 57 Percentage
  • Digital Video IPTV – 65 Percentage
  • Wireless LAN – 60 Percentage
  • Networked Home – 44 Percentage
  • Switch overing – 73 Percentage
  • Security – 38 Percentage
  • Voice – 28 Percentage


Throughout this chapter I discussed the background and the intent of the undertaking. Later chapters, I am traveling to explicate the nexus use, web public presentations and so on.

Then I went through the Cisco System history. Now, Cisco is a immense company and they are gaining over US $ 36.10 billion net income.

Then, I explained the ground for the choice of Cisco company merchandises for my development. They have over 50 per centum market leading across all the divisions.

Principles for taking a routing protocol

With the fast growing of I.T Industry, TCP/IP protocol suit has been in top of the protocol hierarchy. Many different types of sellers make routers to interchange most of import information through web. To accomplish this aim, routers should pass on with each other therefore routers need routing protocols or common linguistic communication to pass on with each other. When we design a big graduated table web we need to choose good, efficiency routing protocols that is really of import. Normally used routing protocols contain RIP v1, RIP v2, IS-IS, BGP every bit good Cisco proprietary protocols of IGRP and EIGRP. You have to choose different routing protocols harmonizing to your web demand.

Connectivity, web topology and web direction are most basic demand of IP web. In add-on to following factors we can see for taking routing protocol.

Compatibility of protocols – When we are choosing a routing protocol we need to do certain compatibility issues because today, there are so many industry doing different networking merchandises.

Topology of web – Topology of web has straight force per unit area on protocol choice. For illustration RIP v2 is non good for complicated big graduated table web, because it has restricted coverage. Therefore we need more complicated routing protocols. Like OSPF and EIGRP.

Strong and Stable – The routing protocols should be strong and stable because other protocols need to guarantee web connectivity. Many types of perturbations will come into position in the web such as hardware or package mistakes or burden reconciliation jobs. Routers are making some sort of determination devising of the web, if routers have hardware or package mistakes, they may bring forth unpredictable web public presentation. Routing protocols must be able hold assorted perturbations for a long clip.

Best way choosing – Routing protocols chief aim is happening the best way in the web and do certain its connectivity. Each routing protocol has different sort of criterion to measure a path quality ( the evaluating restraint contains hop figure, keeping clip, bandwidth and detain etc ) . We must choose suited constellation for different web environments to do certain the best web way.

Management and security – When we are doing the independent systems, different countries will increase the possibility of path unapproachable and cut down path rhythm. It allows us to direction of web more easy and expeditiously. We besides need to see security and policy of routing information exchanging.

What is IP Routing?

IP routing sometimes known as IP forwarding is merely procedure of acquiring an IP package, doing a consequence of where to direct the package following finish and so directing the package. The directing procedure demands to be relatively straightforward, or at least smooth, for a router to direct immense volumes of packages. Ignoring the inside informations of several Cisco optimisations to the sending procedure for an blink of an eye, the internal sending logic in a router works fundamentally as shown in Figure 2-1.

The undermentioned list reviews the chief stairss shown in Figure 2-1.

  1. A router collects the frame and checks the obtained frame cheque sequence ( FCS ) . If mistakes arise, the frame is discarded. The router non try to pick up or retrieve the doomed package.
  2. If no mistakes arise, the router validates the “ Ethernet Type ” field for the package type and takes out the package. Now, the Data Link heading and dawdler no needed and can be discarded.
  3. Assuming an IP package, the router checks its IP forwarding tabular array for the most exact prefix peer of the package ‘s mark IP reference.
  4. The tantamount routing table entry contains the outgoing interface and next-hop router. This information points the router to the contiguity information wanted to do a new Data Link frame.
  5. The router updates the IP heading TTL field, associating a recompilation of the IP heading checksum before doing a new frame.
  6. The router encapsulates the IP package in a freshly made Data Link heading with the finish reference and dawdler with FCS to do a latest frame.

Multi Protocols Routing

Multiprotocol routing includes features for different routing protocols. For illustration, EIGRP and interior or internal routing protocol can back up routing tabular arraies for TCP/IP, IPX/SPX, and others. That is a separate routing tabular array is made for each protocol but utilizing merely one routing protocol.

Multiprotocol routing means the ability to route ( having /sending ) different protocols at the same clip. Multiprotocol routing will hike the sum of routing update information or information on the web because the routers will air each routing protocol individually.


Internet Engineering Task Force has invented OSPF ( Open Shortest Path First ) in the mid 1980s. OSPF is a routing protocol, capable of functioning big heterogenous web. The OSPF protocol is a nexus province protocol based on cost alternatively of hopes. Network Architect had done many research attempts, including Bolt, Newman and Beranek ‘s SPF ( Dijkstra ) algorithm in 1978, country routing in 1986, Dr. Radia mistake tolerant broadcast medium of routing and an early version of IS-IS ( Intermediate System to Intermediate System ) routing protocol.

OSPF protocol has two chief features. The first chief feature is that protocol specification or demand is in the public sphere. The OSPF demand published on RFC 1247. This is called “ OPEN ” . The 2nd feature is SPF algorithm on occasion is referred to as the “ Dijkstra ” algorithm to esteem for the individual for his outstanding creative activity.

The OSPF is grouping to associate province routing protocol group that calls for the forwarding of nexus province advertizements ( LSAs ) to all other routers within the similar country. OSPF LSAs information contains attached interfaces, prosodies and other variables. OSPF routers collect nexus province information and utilize the SPF algorithm to measure the shortest way to each router. Routers with distance vector algorithm send all or a portion of their routing tabular arraies with routing update messages to their neighbours.

The OSPF is a hierarchal protocol. The top most entity is independent system ( AS ) which is a aggregation of OSPF webs running harmonizing to common disposal and portion a common routing scheme. An independent system further divided into figure of countries. Areas include immediate web and terminal users, hosts etc.

OSPF Features

OSPF Operationss

OSPF routing protocol foremost set up contiguities with their neighbour routers. It use “ HELLO ” package to get neighbours. The OSPF routing protocol send and have “ HELLO ” packages to set up and maintain lives the router.

  1. The first thing is to happen neighbours. A router sends and receives “ HELLO ” packets to its adjacent routers. The finish reference that is usually used is a multicast reference. Through this Hello package OSPF identify neighbour is in same AS and country.
  2. Designated Router ( DR ) / Backup Designated Router ( BDR ) election will happen. After that all the other routers become contiguities with the designated routers.
  3. After the connexion constitution so necessitate to synchronise their Link State Database ( LSDB ) . They are interchanging Link State Acknowledgement ( LSA ) and the reception of all LSAs from neighbour routers.
  4. After the update and synchronize of all router LSDBs, the SPF algorithm is run against the information and topographic point best routing way on routing tabular array.
  5. If there is any alteration to the web so a latest LSA must be synchronized throughout the web to update all routers.

SPF Algorithm

In OSPF best way choice based on information collected in the routing database and the SPF algorithm. Each router in an country constructing a tree, where the router is the top and all other web are subdivisions. This tree contains merely webs belong to same country. If router has separate countries so separate trees will be created. OSPF use a metric called cost. Cost has default value defined in RFC 2338 but Cisco has own method to cipher OSPF cost.

OSPF drawbacks and benefits

The OSPF has two O three chief disadvantages, foremost one is OSPF takes more memory and treating power to update topology tabular arraies. Topology tabular arraies are similar in all of routers in an country and it holds all the information for every router and nexus in the country. Second disadvantage is OSPF usage more options and 1000000s of constellations.

OSPF has the capacity to equilibrate monolithic webs and acquire them down to a manageable size. The web ability to organized into countries. The sum of routing informations or operating expense for an OSPF web is radically reduced compared to distance vector protocol. OSPF protocols can cut down the operating expense of the SPF computations by spliting the web into countries. In other words OSPF does non back up unequal burden balance.

The OSPF constellation is small bit more complex. It has more complex web properties and spliting countries etc. The web decision makers, web applied scientists should hold solid apprehension, cognition of computing machine web and information communicating to make high quality constellation every bit good to guarantee OSPF is working good. Everyday OSPF is acquiring popular among web applied scientist therefore this job is non considered as a large job.


Enhanced Interior Gateway Routing Protocol ( EIGRP ) is invented by Cisco Systems in 1992 to get the better of restrictions of RIP v1. EGIRP is a distance vector protocol, classless and it offer more characteristics capablenesss than other distance vector household. It has characteristics and capablenesss from both nexus province and distance vector protocol.

EGIRP is really easy to configure, it is similar to IGRP. EGRP is an advanced distance vector protocol because it has link province protocol characteristics like dynamic neighbor find. EGIRP usage DUAL ( Diffused Update Algorithm ) hence protocol categorized under intercrossed class. This DUAL characteristic is allowed rapid coverage and the warrant of loop free topology.

EGIRP Features

EGIRP has advantages of IGRP. Correctly, calculate routing burden and heterogenous ( assorted ) web protocols support characteristics available on EGIRP. EGIRP computes paths harmonizing to informations such as web bandwidth, web entire hold, web way dependability, way burden and so on. Thus router tabular array is perfect. EGIRP supports IPX, IGRP and Apple talk.

EIGRP is non uses much web resources. Throughout the twenty-four hours today operation, ingestion of web resource is really low degree. Merely hello packages are sent and received on a steady web. If alterations happened merely routing tabular arraies alterations are forwarded to several locations but non full routing tabular array. This will cut down the burden the routing protocols to respective memory. EIGRP has ability to command the package extension and reduces the ingestion of bandwidth. Therefore no 1 can avoid or forestall to transmittal of information.

Third one is loop free and fast convergence. EIGRP has particular algorithm, named DUAL let conveying merely routing alterations. Here one path is update neighbor path and following router updates their neighbour router and so on.

Forth one is related to EIGRP security. The cypher text based hallmark usage with support of MD5 algorithm.

EIGRP support Variable Length Subnet Mask ( VLSM ) like RIP v2 and IGRP. This will minimise traffic of routing information and maintain down the bandwidth use.

EGIRP comes with burden equilibrating characteristic. The equal cost and unequal cost usage to equilibrate the web. EIGRP can make transmittal over unequal cost way but this is non recommended by Cisco Systems.

Last characteristic, like other protocols constellation is really simple. There are no complicated things to configure but you must give excess attention when you are configuring with different protocols and different sellers.

EGIRP Operationss

As I said earlier, EGIPR is a intercrossed protocol because includes both distance vector and nexus province protocol characteristics, classless and Cisco proprietary protocol which means it support merely for Cisco merchandises. It has independent system characteristics like IGRP and contains subnet mask when updating routers but this characteristic non available on IGRP.

OSPF send nexus province packages but EGIRP does n’t direct associate province packages. It sends distance vector updates but the of import thing is EGIRP plants like a nexus province protocol, it synchronize routing tabular array between neighbours at start up. EGIRP supports soap hop numbering 255.

EGIRP has following powerful characteristics

  • Support for IPv4 and IPv6 through protocol dependent faculties
  • Classless protocol like OSPF
  • Support for VLSM
  • Support for router sum-ups and discontinuous webs
  • Very efficient neighbour find
  • Communication utilizing Reliable Transport Protocol ( RTP )
  • Best way choice go throughing through Diffusing Update Algorithm ( DUAL )

Neighbor Discovery

First, need to detect neighbours before start EIGRP routing procedure. There are 3 conditions to happen neighbours such as “ HELLO ” packed and Acknowledgement send and receive, AS figure lucifer and indistinguishable prosodies.

EGIRP following OSPF procedure to keep their neighbor relationships. If router belongs to different AS, so routing information ne’er portion with that router. This is really utile when keeping big graduated table web. When routers receive neighbour updates, they stored that information in a topology tabular array. This tabular array includes all known routers and neighbour information.

Reliable Transport Protocol ( RTP )

The Cisco Systems has another proprietary protocol, named Reliable Transport Protocol ( RTP ) usage to pass on with EGIRP configured routers. This RTP addition the dependability of communicating.

When EGIRP frontward multicast traffic, each EIGRP routers know the neighbours are, and it maintains a list of neighbour inside informations. After 16 efforts, they aware the neighbour is dead. This procedure called dependable multicast.

Diffusing Update Algorithm ( DUAL )

Diffusing Update Algorithm is used to cognizant and maintain best way to each router. This algorithm gives, backup router information, support VLSM, dynamic routing and alternate routing way.

This DUAL allows fastest covergency clip compared to other routing protocols. EIGRP maintain transcript of all neighbour router tabular arraies and calculate best way. If it is traveling incorrect look into the routing tabular array once more and choose new best way. If there is no good options so checked with their neighbour router for aid with way. This quality called “ diffusing ” .

“ HELLO ” packages use to happen neighbours, RTP provides smooth communicating and DUAL is pull offing best way.

EIGRP drawbacks

EIGRP does non hold country construct, therefore it may originate some debatable state of affairs when configuring or covering with high graduated table hierarchy web. Specially, when running OSPF on an endeavor degree web, we are doing the high graduated table web hierarchy by spliting the web into smaller countries. Clearly, EIGRP is non an first-class choice for an ISP degree or endeavor degree web. EGIRP has some restrictions of a distance vector routing protocol such as RIP v1, RIP v2. Anyhow, if you select EIGRP as a routing protocol for a big graduated table web so you must split the web into non equal EIGRP sphere and so relocate or import routing table to each other. Keep in head, this is non best web architecture and you can do merely few webs like this but you can non do big graduated table web.

EGIRP is non back up to Dial on Demand ( DoD ) . An EGIRP protocol exchange “ HELLO ” packets sporadically to keep the neighbour relationships when making this procedure dial up nexus is up. “ HELLO ” packages can convey the dial nexus up but this is non the intent of dial up nexus. The dial up nexus is merely for the backup intent. We have alternate constellation to avoid this thing. We can configure dialer list and dialer group on the interface so “ HELLO ” package will non up the dial nexus. But the job is we are blowing valuable router resources to avoid this thing. The OSPF takes benefit at this instance supplying DoD support.

The EIGRP DUAL algorithm provides fast convergence and loop free features. Basically, the DUAL algorithm is working by directing information to its neighbour sing the active paths ( dubious paths ) , so convergence is having the answer. If the paths are dubious or active paths for its neighbour excessively, so neighbour besides send information to their neighbour. This procedure will be carry on and on boulder clay obtain the successful answer or after a period of clip, the peculiar paths will be decided non available and acquire discarded from the routing tabular array. However in some state of affairss, the active paths will be put into active position for after long period of clip. This state of affairs is really severely affected the fast convergence characteristic. OSPF has non this sort of state of affairs at all but EGIRP is still provides fast convergence among other routing protocols. EGIRP is small bit slow in following instances, in a long narrow web, if something has changed it takes long clip to direct the “ HELLO ” package from one routing side to other routing side.

Let state like this, EGIRP configured to to the full engage with neighbour relationship and communicate to other routers, exchange information within all routers, but if it is airing web that means EIGRP kill a batch of bandwidth. In OSPF select DR and BDR routers and merely wants to configure contiguity with DR so exchange nexus province advertizement within the web. This will salvage batch of bandwidth resources.

Cisco Systems introduced this EIGRP protocol, It is a proprietary protocol and non a unfastened criterion protocol. An lone Cisco merchandises can run on this EIGRP protocol and Cisco System has the to the full right to utilize this protocol and make alterations. They do non necessitate anyone ‘s blessing to alter or modify this protocol. If they have done alterations without inform to clients or other merchandise sellers, so it may make more debatable state of affairs because Cisco system has the market leading. But OSPF is other manus, OSPF comes with IETF and it is unfastened criterion routing protocol. Most of merchandises support to this protocol without any job and there are no much compatibility issues with this protocol.


Throughout this chapter I have discussed routing, multiprotocol routing, OSPF and EIGRP. I hope now you have some thought of routing, background of routing protocols and so on.

IP Forwarding tropic explicate how package are directing and having throughout the web. Figure 2-1 used to explicate this routing procedure. In add-on to step by measure I explained the map of routing procedure.

Multiprotocol means more than one protocols running on the web. I merely discussed this tropic because it will assist you to understand future Torrid Zones.

I have discussed more inside informations things in OSPF such as history, operations, advantages and drawbacks. Mid 1980, Engineering Task Force invented OSPF. It contains two chief features one is specification of public sphere other one is SPF algorithm. OSPF operation has given the thought of OSPF procedure, such as HELLO packages, DR / BDR procedure etc. At last, I converse benefits and drawbacks.

Then I went through EIGRP. EIGRP is a latest version of IGRP and it is a intercrossed protocol. It used DUAL algorithm engineering to choose best way, “ HELLO ” package usage to happen the neighbours and RTP provides smooth communicating.

In add-on to there are so many bids use to verify and debug routing procedure. Which are as follows

  • show ip ospf interface
  • show ip ospf neighbour
  • sShow information science protocols
  • debug information science ospf packages
  • debug information science ospf hullo
  • debug information science ospf adj

EIGRP Configuration

However EGIRP support IP, IPv6, IPX and AppleTalk protocols. That means we can configured EGIRP with this protocols. EGIRP has two constellation manners, named router constellation manner and interface constellation manner. Router constellation manner allows set planetary features and recognizes type of web run on EGIRP. Interface constellation manner usage to modify prosodies, timers and bandwidth. EGIRP constellation is easier than OSPF constellation.

In add-on to above bids there are so many other bids. Which are as follows

  • debug egirp package – Able to see transmittal between neighbour routers
  • debug information science egirp presentment – Changes and updates on an EIGRP web

Comparing OSPF & A ; EIGRP

OSPF and EIGRP are both superb routing protocols and every one provides a typical set of benefits for implementing and planing a big graduated table web such as ISP degree web. These two protocols can be used for a generous scope of webs from little, campus, regional webs to big endeavor, planetary degree web systems. The common inquiry is often, asked is, “ Which protocol is the best? Either OSPF or EGIRP ” This is good and complicated inquiry, as both protocols ( EIGRP and OSPF ) have their ain benefits. This chapter evaluates EIGRP and OSPF and provides status to contrast the two protocols, either EIGRP or OSPF and make up one’s mind which is the most appropriate for your web demand. The undermentioned conditions have been considered so that chief discriminating characteristics can be evaluated when taking the routing protocol which one is the best lucifer to your web demands. This chapter and chapter 2 covered the basic operations, maps and characteristics of each protocol. It evaluates the related things of each protocol.

Network Design – EGIRP does n’t necessitate hierarchal web topology but OSPF needs it. It is good design wont to constructing EIGRP hierarchically but it is non necessary. As a consequence, EIGRP is more flexible from a topology point of position but still you must careful when design the web decently. Occasionally all the adaptability of EIGRP makes unacceptable web design, while OSPF points you to construct in a anchor of a web. OSPF besides has limitations in figure of routers in an OSPF country ( max 50 depends on the design ) and figure of countries per router ( up to 3 may be vary harmonizing to design ) . Therefore constructing an OSPF web could be more ambitious and curtailing than constructing an EIGRP web.

Ease of Use – Because OSPF wants a hierarchal construction, needs a reviewed reference construction, and needs physically configured outline references. It has to be harder to implement. In add-on, the particular regulations for the many types of countries and LSA types are theoretically more complex to recognize. Though, all these demands can be attractive and support a big scalable web ( ISP Level ) , when ended suitably. EIGRP can besides necessitate some complex and advanced constellation when to configure particular characteristics. However, many people sense EIGRP is bendier than OSPF and web programs are easier to use utilizing EIGRP.

Neighbors – EIGRP signifiers contiguities ( neighbour ) and send / receive ( interchanging ) routing updates with each neighbouring router. While OSPF does an election procedure for a DR ( Designated Router ) and BDR ( Backup DR ) which operate as a “ distribution ” location for routing information. In OSPF, routers merely construction a full contiguity to the DR and BDR ( there is merely one DR / BDR per web country ) . This means that all things being equal OSPF can more resourcefully keep a full interconnect of neighbouring routers per interface. This point is peculiarly valid on high velocity WAN and LAN media. As a guideline of pollex, this concern gets to be of import at about 20 neighbours per routing interface, but depends on routing tabular array, size of routing tabular array, routing platform ( ISO version ) , router use etc.

Although, tonss of web programs do non hold a immense figure of neighbours per routing interface. They have a 1000000s of neighbours per router. In these state of affairss, there are design limitations refering the figure of routers in an OSPF country and the figure of countries maintained per router ( Max 50 depends on the constellation ) . It is indispensable to observe that both OSPF and EIGRP have be aftering concerns sing neighbours. These be aftering concerns depend on batch of factors contain routing tabular array, size of routing tabular array, routing platform ( ISO version ) , router use, etc. but a normal regulation of pollex is that OSPF may hold more neighbours per interface. While EIGRP allocates more design adaptability for batch of neighbours per router.

Path Filtering and Redistribution – Filtering router procedures is non easy in OSPF contain router. “ Distribute-list in ” characteristic does non run in OSPF routing procedures. The “ Distribute-list out ” operates merely on the paths with configured redistribute map from other routing procedures into OSPF. Furthermore, OSPF path distribution may merely be carried out at AS boundaries or OSPF country. The EIGRP information could be filtered and distributed at all interface and at every spot boundary. Hypothetically apportioning several hierarchies based on routing topology. Thus EIGRP is much more flexible and easier to run when executing path filtering and redistribution. Equally good as EIGRP is far better quality to OSPF in inward path and outbound path filtrating on an each interfaces.

Route Summarization and Configuration – By default, EIGRP perform an automatic summarisation procedure but OSPF needs to configure each and every drumhead reference. As we talk about earlier, EIGRP can be easier to configure and implement. Although in many big graduated table webs ( ISP degree or more ) with meshed webs and / or redistribution terminals, no demand much careful consideration to summarisation procedure. Otherwise it can ground for routing cringles and stability problems. You have to carefully see the routing topology and addresses scheme, defective car summarisation is a on a regular basis encountered problem to tonss of terminal users. Of class, you can acquire more or less these problems in EIGRP with interface drumhead reference bids or OSPF configuring country scope bids but it gets extra stairss, good pattern and some more information of how the routing protocol operates. OSPF needs all manual drumhead bids and hence wants more consideration to this routing procedure. With EIGRP, careful concerns should besides be given to summarization procedure even if you are utilizing the automatic summarisation options. Not runing summarisation right with either protocol can ground terrible web crisis.

Convergence – To better a web routing topology changes, EIGRP comes with DUAL engineering ( Diffusing Update Algorithm ) which make available rapid convergence if a executable replacement is available. OSPF forwards a LSA and calculates it once more the SPF algorithm ( sometimes known as Diskjtra ) . From this point of view, EIGRP may convergence velocity than OSPF and may necessitate less CPU processing clip. Although convergence is non independent factor, it requires one or many factors including topology database, routing metric, type of failure etc. so an ultimate decision / stoping can non be made here. When a executable replacement does non available, EIGRP will get down question neighbouring routers for the lost path which so inquiring their neighbours constructing a turning tree or web hierarchy of questions until the path is established or considered to be non available. In this state of affairs, the velocity of convergence requires on so many things including the web routing topology and it is non possible to clearly province which protocol is faster.

Memory and CPU – EIGRP forwards limited ( partial ) updates and if routing topology alteration occurred, it will get down directing this updates otherwise non direct any update. This is the 1 and lone clip you can acquire update from the EIGRP routing topology. The handiness of a “ executable replacement ” in EIGRP restricts the consequence of routing database alterations to straight affected routers and other paths. The OSPF multicasts LSAs to all EIGRP routers in the country taking a routing database alteration and forward periodic routing database updates. Memory and CPU ingestion semen into history when reflecting the EIGRP routing table size, figure of neighbours and how on a regular basis the EGIRP routing protocol is actively running it is DUAL algorithm. OSPF is usually more CPU exhaustive on the DR router and this router must hold more memory and CPU power to keep this undertaking. Besides, OSPF may necessitate more CPU and memory resources on other routers with or without OSPF in the web.

Vendor Compatibility – OSPF is carried by batch of router sellers such as Cisco, Nokia etc. and as I said earlier, is an industry criterion RFC 1583 but EIGRP is a proprietary protocol introduced by Cisco System. EGIRP is non a seller independent protocol and it is supports merely Cisco merchandises. Although, you have to be careful when inter linking OSPF with different seller routers because each and every seller ‘s OSPF executions is non similar, sometimes it may non be able to manage big OSPF routing table sizes ( some sellers supports 200 maximal paths including 4 neighbours but it may be vary harmonizing to seller to seller ) . It should besides be distinguished that multiple routing protocols could be supported on a router if it is possible to configure EIGRP and still bury connect with OSPF routers by adding another separate routing procedure.

Route Selection – OSPF makes the interface cost ( cost, utilize several techniques different sellers but all are really similar ) to make up one’s mind the shortest way. EIGRP uses a routing database and calculate shortest waies taking nexus bandwidth and hold as status. EIGRP offers more flexibleness, manage and control in taking the best routing way.

Routing Overhead – OSPF communicate with routing database each and every 30 proceedingss and update Link State Advertisements ( LSA ) at any clip a routing database alteration return placed. EIGRP uses a topology database which does non hold to be sporadically update and does non direct LSAs when the web topology amendments. As an option, EIGRP forwards out questions merely when an acceptable “ executable replacement ” non available to an effort to happen a path. Therefore, depending on the web routing topology, routing province, and router constellation, EIGRP is a good organized than OSPF by cut downing routing information exchanged.

Link Bandwidth Conservation – OSPF utilizes whatever bandwidth it wants. EIGRP will utilize merely 50 % ( default value ) of a nexus bandwidth in a bad state of affairs. In EIGRP, you can configure bandwidth ingestion parametric quantities but OSPF does non supply this sort of installation. Besides, EIGRP allow you to alter “ hello timers ” and “ keep down timers ” on peculiar interfaces to restrict the bandwidth used and to hike web convergence and dependability. EIGRP to boot save WAN bandwidth by stamp downing ACKs and directing unicast informations packages to this undertaking. Therefore EIGRP is much more suited for WAN applications where connexion bandwidth is valued.

Reliable Delivery of Routing Information – EIGRP gives more dependable bringing of routing information, update, and recognition and answer packages to do certain routing question is non lost. OSPF multicasts send information and accept recognitions for the packages. Both protocols support dependable mechanism to pass on routing information.

Security – OSPF gives message digest hallmark cardinal security and watchword for routing information. EIGRP besides gives hallmark directing an encrypted key. Both protocols have a first-class security characteristics available.


Books [ B… ]

  1. Patrick J. Conlan, 2009. Cisco Network Professional ‘s Advanced Internetworking Guide. Sybex.
  2. WilliamR.Parkhurst,2002. Cisco OSPF Command and Configuration Handbook ( CCIE Professional Development ) . Cisco Press.
  3. Internetworking Technologies Handbook. Chapter 46. Cisco Press.
  4. EIGRP Network Design and Solution. Cisco Press.
  5. OPNET IT Guru Academic Edition.
  6. Wendell Odom, Rus Healy, 2008. CCIE Routing and Switching Exam Certification Guide. Cisco Press.
  7. Todd Lammle. Cisco Certified Network Associate Study Guide. 6th Edition. Sybex

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