Because of this, routes are summarized to classful address at network boundaries in the routing updates. The add path support in eigrp feature enables hubs in a single dynamic multipoint vpn dmvpn domain to advertise multiple best paths to connected spokes when the enhanced. Cef on r3 overrides the perpacket balancing behavior of process switching with perdestination load balancing. A path has to be a feasible successor route to be used in unequal load balancing. We can verify the eigrp load balancing using the show ip protocols command. To see the full effect of eigrp equalcost load balancing, temporarily disable cef and route caching so that all ip packets are processed individually and not fastswitched by cef. Hi all, i am trying to configure equal cost load balancing on a remote site that connects to the head office using a cisco 2901 router. Now its time to do a little unequalcost balancing, using this network.
Have you ever wondered why among all igps only eigrp supports unequalcost load balancing uclb. The command displays the number of equalcost paths currently configured on the router. The eigrp is commonly the routing protocol of choice when using the network with no. In this lesson, well take a look at eigrp enhanced interior gateway routing protocol which is ciscos routing protocol. Before jumping in the ins and out lets run through a few things first when it comes to eigrp load sharing, also refereed. Eigrp makes it easy for us the network engineers to make this happen. Does this mean that for eigrp, equal cost load balancing doesnt increase your bandwidth, it just divides the speed of one link. Many of you have problems finding a comprehensive guide to load balancing for eigrp. This paper presents a framework for global server load balancing of the web sites in a.
For more information on variance, refer to troubleshooting. Pdf improvement of performance of eigrp network by using a. The configuration supports unequalcost load balancing. Eigrp variance command example this tutorial will demonstrate how you can use the eigrp variance command to make eigrp load balance over feasible successors. This article demonstrates the traffic engineering with eigrp using unequal cost load. Configure and verify eigrp stubs, eigrp load balancing and eigrp neighbor relationship and authentication. This router connects to two wan links which has the same bandwidth. Eigrp is a ciscoproprietary routing protocol that is based on igrp. For equal cost load balancing allboth routes have a. We often come across the requirement where we have to perform the load sharing in dualhomed network scenario. A significant advantage of eigrp and igrp over other routing protocols is the support for unequalcost load balancing. By default, eigrp supports equalcost load balancing over four links.
The degree to which eigrp performs load balancing is controlled. As with autosummarization, the router performing manual summarization will add the. Cisco ios, by default, allows eigrp load balancing for four equalcost paths routes. You can play with the delay interface command to adjust this. Providing load balancing and introduction the concept of. How does unequal cost path load balancing variance work.
Eigrp balancing load fingerinthenet for english guy. Network load balancing, load balancing as a service, cloud computing. There are two things you must be aware of when using eigrp unequalcost load balancing, and well cover those and a whole lot more in this lab in the previous lab, we saw equalcost load balancing in action. They will choose which of those routers has the best metric. In this video we discuss load balancing with eigrp.
Eigrp equal and unequal cost load sharing eric leahy. Configuring eigrp maximum paths free ccna workbook. By default, eigrp has the auto summary feature enabled. The configuration supports equalcost load balancing. Enhanced interior gateway routing protocol nanopdf.
Download cisco ccnp routing pdf study guide snabay. On r1, view the routing table and verify that r1 is loadbalancing to 10. The output in figure 1 illustrates the topology for that we will use in this lesson and figure 2 illustrate that r1 is using the default equal. How to configure eigrp variance to load balance traffic across unequal cost links.
Any eigrplearned route with a metric less than 3 times the successor. Bgp in large networks scaling bgp across multiple locations download ebook. To better understand the equalcost load balancing concept, consider the following example. Rip routing information protocol automatically performs equal cost load balancing. How does unequal cost path load balancing variance. In this situation, eigrp sends two packets to eca and one packet to eba. Even better it will share traffic in a proportional way, if you have a feasible successor that has a feasible distance which is 5 times worse than the. The manual summarization is needed on a hub to advertise the default route to a spoke. Eigrp can also balance traffic across multiple routes that have different metrics, which is called unequalcost load balancing. In this post i would like to explore unequal cost load balancing with eigrp and particularly how we configure eigrp in order to achieve load balancing. This unique feature on eigrp is called unequal cost load balancing and its very easy to be implemented. Which two statements about eigrp load balancing are true. This means that, even if variance is set to 3, the eda path is not selected for load balancing because router d is not a feasible successor.
But generally, something is wrong with your output, path via 192. Is there any special reason why only eigrp supports. Equalcost means that multiple routes must have the same metric to reach the destination, so that router can. Eigrp uses diffusing update algorithm dual to determine the best path among all feasible paths. Basic cisco router eigrp configuration pluralsight. Configure and verify equalcost load balancing with eigrp. Ccnp route chapter 2 lab 21, eigrp load balancing version 7. Eigrp also supports loadbalancing across routes with an unequal metric. Implementing the variance command on the router that is connected to the 4 routers will allow that router to see the best metric then multiply it by. Before jumping in the ins and out lets run through a few things first when it comes to eigrp load sharing, also refereed to as load balancing sometimes.
In this scenario, the topology and ip addressing is as shown in figure below and the routing protocol has been configured using eigrp with as number 99. Eigrp is a ciscoproprietary hybrid routing protocol, incorporating features of. Equal cost load balancing with rip on packet tracer. Eigrp adheres to the following hybrid characteristics. Eigrp load balancing configuration example certiology. Hi there, i have a question on how to check on how to load balancing works on eigrp. How to configure and verify eigrp stubs, eigrp load balancing and eigrp. We must use the variance command to tell eigrp to loadbalance across unequalmetric links. Since both eigrp routes are placed in routing table with different cost traffic should be load balanced unequally. The enhanced interior gateway routing protocol eigrp is an enhanced version of the interior gateway routing protocol igrp developed by. In this way, eigrp provides both unequal cost path load balancing and intelligent load balancing.
Equalcost means that multiple routes must have the same metric to reach the destination, so that router can choose to load balance across equal cost links. How to test eigrp loadbalancing solutions experts exchange. Refer to the load balancing section of enhanced interior gateway routing protocol for more information on how eigrp load balances traffic over unequal cost links. If the feasible condition is not satisfied, the variance command is not considering the route for load balancing. Eigrp unequal cost load balancing trafficengineering. This document describes how to troubleshoot the most common enhanced interior gateway routing. Eigrp load balancing and metrics overviewdescription expected duration lesson objectives course number expertise level overviewdescription.
I have three router going to same site, eigrp running. R1 has an fd of 5 0 via r12 the fd via r11 is lower than the fd via r12. I tried shutting down 3 of my 4 links and retesting and it gave me the same result. Cisco ios software supports equal cost load sharing for a default of up to four paths for all routing protocols. Using routing capabilities is a must in todays evolving networks. Configure load balancing on cisco eigrp mustbegeek. Your traffic share count is correct and the recommended setting is to leave the default per flow load balancing which will be ok for you. Eigrp enhanced interior gateway routing protocol eigrp is a ciscoproprietary hybrid routing protocol, incorporating features of both distancevector and linkstate routing protocols.
Configure and verify unequalcost load balancing with eigrp. Topology r1 is the router we will be doing our tests from. Eigrp equalcost load balancing equalcost load balancing is a routers capability to distribute traffic over all the routers that have the same metric for the destination address. Eigrp can exchange routes for ipv4, ipv6, appletalk and ipxspx. Configure load balancing on cisco eigrp using unequal routes. Recently, i was asked a question regarding traffic load balancing across several links and i was able to provide two options that i thought would work. In this lab i will explore equal and unequalcost loadbalancing for eigrp and will explain how eigrp calculates its metric values. Eigrp is an exceptional option as it mixes a number of the major advantages of other routing protocols including fast convergence, support for very large networks, efficient, support for load balancing and. A path can be used for load balancing only if it is a feasible. If you are unfamiliar with distance vector and rip i highly recommend to read my introduction to rip first before continuing eigrp stands for enhanced. In this tutorial, you will learn about different types of eigrp load balancing. Abstract we propose a routing and loadbalancing approach with the primary goal of. By default, eigrp will automatically loadbalance across equalmetric routes four by default, six maximum.
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