Lets take a look to figure below and configure this topology via eigrp step by step. Pdf improvement of eigrp protocol routing algorithm with the. Eigrp or enhanced interior gateway routing protocol is a cisco proprietary technology for routing. It calculates the best route to a destination using metric value that is based on the link bandwidth and delay.
Since both eigrp routes are placed in routing table with different cost traffic should be load balanced unequally. By setting the variance to 10 we are telling the router to load balance over routes that have an fd of up to 10 times worse than the fd of the successor route. Sep 24, 2016 eigrp path selection and load balancing eventhefield. The degree to which eigrp performs load balancing is controlled by the variance multiplier router configuration command. Eigrp makes it easy for us the network engineers to make this happen. Use the variance n command in order to instruct the router to include routes with a metric of less than n times the minimum metric route for that. Nov 16, 2011 asa load balancing over eigrp not working we have an asa 5540 running 8. It support unequal and equal cost path loadbalancing. Eigrp uses metric calculations similar to those that igrp uses, and eigrp supports the same unequalcost path load balancing as igrp. If you are running ospf, dont try any method of load balancing.
By default, eigrp will automatically load balance across equalmetric routes four by default, six maximum. Using the openflow protocol in practical routing networks. Eigrp uses diffusing update algorithm dual to determine the best path among all feasible paths. This tutorial explains how to configure eigrp routing protocol in cisco routers step by step with practical example in packet tracer. Dec, 2011 the default setting for load balancing under eigrp is perdestination. This means that, even if variance is set to 3, the e. Eigrp adheres to the following hybrid characteristics. Eigrp stands for enhanced interior gateway routing protocol and is a routing protocol created by cisco. The multiplier is a variance value, between 1 and 128, used for. There has never been a shortcut for a load balancing. To better understand the equalcost load balancing concept, consider the following example.
But generally, something is wrong with your output, path via 192. Lets take a look at an example of how eigrp can do load balancing. Load balancing with eigrp all of our interior gateway protocols can perform equalpath load balancing on up to 4 routes by default. To control the maximum number of parallel routes that the enhanced interior gateway routing protocol eigrp can support, use the maximumpaths command in the appropriate configuration mode. By default, eigrp supports equalcost load balancing over four links.
Also its proposed the modified algorithm of load balancing between paths that let to offload the most efficient routing node while the network is. We must use the variance command to tell eigrp to loadbalance across unequalmetric links. Equal and unequal cost load balancing eigrp support equal and unequal cost load balancing equal cost load balancing is enabled by default. I have set the variance, set trafficshare to balanced, enabled ip cef and on each interface set ip load sharing perpacket. Then the degree to that eigrp performs the load balancing is controlled by a variance multiplier router configuration command. If you want eigrp to do equal costpath load balancing you can use maximupaths command to set the paths to it. In this lab i will explore equal and unequalcost loadbalancing for eigrp and will explain how eigrp calculates its metric values. By default, eigrp will automatically loadbalance across equalmetric routes four by default, six maximum. Use show and debug commands for the eigrp topology table. Eigrp also supports loadbalancing across routes with an unequal metric. Eigrp, however, can also load balance over unequal cost links. As were working with only one destination, we will still end up using one link for all traffic, so it is better to implement perpacket loadbalancing.
Jul 10, 2014 eigrp introduction video by sikandar shaik dual ccie. Just like ospf or rip, eigrp can do load balancing but it has one more trick in its hat. Eigrp load balancing every routing protocol supports equal cost path load balancing. In the next article, we will consider another solution to the traffic load balancing scenario which deals with policybased routing and ip sla tracking. Configure load balancing on cisco eigrp mustbegeek. Every routing protocol supports equal cost path load balancing. How to test eigrp loadbalancing solutions experts exchange. Eigrp applies an administrative distance of 90 for routes originating. May 11, 2011 eigrp unequalcost load balancing eigrp can also balance traffic across multiple routes that have different metricsthis is called unequalcost load balancing. How do i verify, whether is it doing load balancing or not.
In addition, interior gateway routing protocol igrp and eigrp also support unequal cost path load balancing. On r1, view the routing table and verify that r1 is load balancing to 10. Configure and verify equalcost load balancing with eigrp. After overview of eigrp, it is time to take a look at eigrp configuration. It will connect through r2 and r3 to ip address 124. As i know that eigrp can do unequle cost load balancing. Eigrp configuration, bandwidth and adjacencies chapter 2. In this lab we will configure rip and will observe load balancing with equal cost load balancing in packet tracer. May 04, 2006 load balancing has always been a trivial issuse for many cisco engineers. Eigrp also supports load balancing across routes with an unequal metric. 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. It is sometimes referred to as a hybrid routing protocol because it has characteristics of both distancevector and linkstate routing protocols. Nov 06, 2016 for equal cost load balancing allboth routes have a metric of 1.
Rip and ospf both can do loadbalancing but the paths have to be equal. The unequalcost loadbalancing with eigrp is subject to one aditional restriction, the best metric is selected fd and multiplied by the variance, so anything in that range will be used to load balance over. Eigrp configuration, bandwidth and adjacencies chapter 2 lab. Eigrp is called a hybrid or advanced distance vector protocol and most of the rules that apply to rip also apply here. Configure the network above with eigrp using autonomous system number 90. When there are several routes with an equal metric value, by default all dynamic routing protocols, including eigrp, will used all these routes to forward packet in load balance style. A path is not selected for load balancing because router d is not a feasible successor. Sep 19, 2011 eigrp makes it easy for us the network engineers to make this happen. All of our interior gateway protocols can perform equalpath load balancing on up to 4 routes by default.
Jul 26, 2010 since eigrp does unequal cost load balancing at a ratio equal to the calculated fd out of two interfaces, you have to use the math previously mentioned. How does unequal cost path load balancing variance work. Here, the multiplier is the variance value in between 1 and 128 which is used for the. How does unequal cost path load balancing variance. Each key chain can have many keys, just like in real life. Cisco ios software supports equal cost load sharing for a default of up to four paths for all routing protocols. A simple tip out here is that ospf will do equal cost lad balancing by default so if you want to load balance between two links, simply make there cost. We must use the variance command to tell eigrp to load balance across unequalmetric links. How does this can work and what will be router configuration to make load balancing. Path first ospf, and interior gateway routing protocol igrp. Here in this case if you dont use maximumpaths command under the eigrp configuration it will take only one path into account. 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. If i want to load balance on more than 4 equalcost paths, i can do that.
Identify successors, feasible successors, and feasible distances. I will talk about the feasible distance, the metric weights, offsetlist, the different methods we can use to change traffic sharing among multiple unequal cost paths with eigrp and. Eigrp overview eigrp enhanced interior gateway routing protocol is an advanced distance vector routing protocol. It is also important to note that cisco ios release. We can verify this by looking at the output of show ip protocols, it will tell us what the maximum path value is. Feb 19, 2020 eigrp can also balance traffic across multiple routes that have different metrics, which is called unequalcost load balancing. I have an ipsec gre tunnel using comcast, as well as a point to point t1 that i want to balance across. But eigrp can support unequal cost path load balancing.
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. Chapter 2 lab 22, eigrp load balancing topology objectives. By configuring the variance value of 2, the minimum metric is increased to 60 30 2 and all the routes that have a metric of less than or equal to 60 and satisfy the feasibility condition will be used to send traffic. I have a question on how to check on how to load balancing works on eigrp. The multiplier parameter for the variance command is a value from 1 to 128, used for load balancing. Mar 31, 2015 also, the reported distance of neighbor d is 25, which is greater than the feasible distance fd of 20 through c. Cisco router how to configure eigrp to load balance across. Rip equal cost load balancing on packet tracer networking. The type of load balancing per packet or per destination depends on the type of switching being done in the router. To remove the maximumpaths command from the configuration file and restore the system to its default condition with respect to the routing protocol, use. Routes with equal feasible distance are installed by default in the. The degree to which eigrp performs load balancing is controlled with the variance command.
Today i will show how to configure ospf load balancing, if we follow bellow example we see a client is connected through two wan connections with two broadband routers that both are use for internet routing. Configuring eigrp maximum paths free ccna workbook. Step by step eigrp configuration example networkel. Eigrp enhanced interior gateway routing protocol eigrp is a ciscoproprietary hybrid routing protocol, incorporating features of both distancevector and linkstate routing protocols. Eigrp configuration is really awesome and not so hard if you compare with ospf or etc. Eigrp equal and unequal cost load sharing eric leahy. I am trying to configure unequal cost load balancing in eigrp and am a little confused about a couple of parts.
Verify your configuration by using the show ip route command. If you configure this feature in the example topology discussed above, both spoke1 and spoke2 will be advertised to spoke3 and spoke4 as best paths to network 192. I have three router going to same site, eigrp running. Configure eigrp to load balance across unequalcost paths cisco router 5. Jun, 20 now lets configure unequalcost load balancing to make use of the link via e10. This command displays a brief listing of the interfaces, their status, and the ip address and subnet mask configured in prefix format xx for each interface. Jun 06, 2014 building on that knowledge, we have seen how to use eigrp to achieve unequal cost path load balancing through the variance command. Aug 14, 2017 the add path support in eigrp feature enables eigrp to advertise up to four additional paths to connected spokes in a single dmvpn domain. Originally, it was only available on cisco hardware but since a few years, its now an open standard. Eigrp path selection and load balancing eventhefield. Load balancing is a standard functionality of the cisco ios.
Pdf improvement of performance of eigrp network by using a. In this lab, you need to configure equalcost load balancing on per destination or per packet basis. Topology r1 is the router we will be doing our tests from. We must use the variance command to tell eigrp to loadbalance across these. Aug 12, 2012 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. The routers run bgp facing out and eigrp facing in, with the asa also running eigrp for the same as. To enable perpacket loadbalancing we will need to check our cef cisco express forwarding settings. 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 successor then traffic will be shared in a 5. Variance 1 in eigrp means unequal load balancing is disabled,it supportequalcost load balancing in eigrp, if the multipoint network has different speeds allocated to the vcs,take the lowest cir and simply multiply it by the number of circuits. Nov 22, 2006 bydefault eigrp does equalcost path load balancing upto 4 equal cost paths. The eigrp balance traffic across the multiple routes which have different metrics which is called as unequal cost load balancing. Total delay from path using jackie is 900 multiply that times 5 and the total delay for the other path needs to be 4500. Eigrp puts up to four routes of equal cost in the routing table, which the router then load balances.