EIGRP Metric
- Bandwidth (BW)
- Delay (DLY)
- Reliability (RELIABILITY)
- Load (LOAD)
- MTU
How do I calculate the EIGRP load metric?
1) Bandwidth 2) Delay 3) Reliability and 4) Load EIGRP Metric = 256* ( (K1*Bandwidth) + (K2*Bandwidth)/ (256-Load) + K3*Delay)* (K5/ (Reliability + K4))) By default, the values of K1 and K3 are set to 1, and K2, K4 and K5 are set to 0.
What are EIGRP k-values?
K-Values are the most confusing part of EIGRP. Usually newbies take K Values as EIGRP metric components. K Values are not the metric components in themself. They are only the place holder or influencer for actual metric components in metric calculation formula.
What is the EIGRP bandwidth metric formula?
• Bandwidth = 10000000/bandwidth (i), where bandwidth (i) is the least bandwidth of all outgoing interfaces on the route to the destination network represented in kilobits. destination network, in tens of microseconds. Note: If K5 is set to zero, the last part of the EIGRP metric calculation formula (K5/ (Reliability + K4)) is taken as 1.
What is the EIGRP metric formula for K5?
Note: If K5 is set to zero, the last part of the EIGRP metric calculation formula (K5/ (Reliability + K4)) is taken as 1. Here we have two paths from Source Network to the Destination Network. Along Path 1 we have Fast Ethernet links (Bandwidth 100 Mbps) and along Path 2 we have Serial links (Bandwidth 1.544 Mbps).
How do I set EIGRP metric?
The delay value used in the EIGRP metric calculation is the delay in 10's of microseconds. So to calculate the Delay value, simply divide the DLY in the show interface command by 10. The Delay Value of 10 will be plugged into our simplified EIGRP Metric formula we derived earlier.
What metric components does EIGRP use by default?
To calculate the cost of a route, EIGRP uses a composite metric calculation formula. The formula can use five components in the calculation. These components are Bandwidth, Delay, Load, Reliability, and MTU. By default, the formula uses only Bandwidth and Delay.
Which metric is used by OSPF?
cost metricOSPF uses a cost metric that represents the status of the link and the bandwidth of the interface in an algorithm to determine the best route to a destination. The algorithm used is called the SPF (shortest path first) or Dijkstra algorithm.
What is K value in EIGRP?
K values are integers from 0 to 128; these integers, in conjunction with variables like bandwidth and delay, are used to calculate the overall EIGRP composite cost metric.
What is the default variance of EIGRP?
EIGRP provides a mechanism to load balance over unequal cost paths throungh Variance Command. Variance is a number (1 to 128), multiplied by the local best metric then includes the routes with the lesser or equal metric. The default Variance value is 1, which means equal-cost load balancing.
Does EIGRP load balance by default?
EIGRP load balancing By default, EIGRP supports equal-cost load balancing over four links. Equal-cost 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.
Which factors are used by default in EIGRP to identify the least cost?
By default, EIGRP only performs equal-cost load-balancing. If the variance command is used, the variance multiplier controls the multiplier that is used to determine whether load-balancing will be performed for paths to the same destination with different metrics.
What is the default hold interval for EIGRP?
EIGRP uses a default Hello timer of 5 seconds and a default Hold timer of 15 on LAN interfaces.
How does EIGRP calculate the total metric?
Let us compute the metrics. EIGRP calculates the total metric by scaling the bandwidth and delay metrics. EIGRP uses the following formula to scale the bandwidth:
What is EIGRP measure?
The EIGRP Metric is a combination of a measure of the entire path's cumulative delay, and the minimum bandwidth across the entire path. The delay value is value assigned to each 'hop' based upon that interface's speed.
What is EIGRP bandwidth?
EIGRP uses the minimum bandwidth on the path to a destination network and the total delay to compute routing metrics. Although you can configure other metrics, we do not recommend it, as it can cause routing loops in your network. The bandwidth and delay metrics are determined from values configured on the interfaces of routers in the path to the destination network.
What is metric value?
The Metric value is a 32 bit value, which means it can be any number between 0 and 4.2~ billion. The Metric is only considered if the network is the the same size, and the route is learned from the same routing Protocol. Which means what EIGRP considers as a metric will never be compared to what OSPF will consider a network.
Why is the EIGRP metric so high?
In regards to the EIGRP metric being so high - part of the reason is because EIGRP multiplies its metric by 256 in order to be backward compatible with IGRP (EIGRP's predecessor). As per this Wikipedia entry:
Why is EIGRP preferred over OSPF?
Because if a route is learned from OSPF and EIGRP, the EIGRP route will always be preferred because its Administrative Distance is lower (90 vs 110).
What is the value of EIGRP?
We know the value for EIGRP Metric is 256 * (BW+Delay). If we take 28160 and divide it by 256, we get 110. Which means BW+Delay equated to 110.
How many components does EIGRP use?
EIGRP uses four components out of five to calculate the routing metric.
What are the components of EIGRP?
This tutorial explains EIGRP Composite Metric calculation formula and components (K1– Bandwidth, K2-Load, K3-Delay, K4-Reliability and K5-MTU) step by step in detail with examples. Learn how EIGRP Composite Metric Formula calculate and select the shortest path to reach the destination.
What is the EIGRP routing protocol?
Enhanced Interior Gateway Routing Protocol uses composite metric calculation formula to calculate and select the best available route for destination. This formula uses five metric components. These are Bandwidth, Load, Delay, Reliability and MTU. In order to understand how EIGRP composite metric calculation works, first we have to understand these five key metric components.
What is a K value in EIGRP?
K-Values are the most confusing part of EIGRP. Usually newbies take K Values as EIGRP metric components. K Values are not the metric components in themself. They are only the place holder or influencer for actual metric components in metric calculation formula. So when we enable or disable a K value, actually we enable or disable its associate metric component.
Why does the highest bandwidth pick the lowest instead of the highest?
You may surprise why it picks the lowest instead of the highest? Well picking the highest bandwidth doesn’t give us a surety of equivalent bandwidth throughout the route. It’s a maximum cap which means we will get its equivalent or lower bandwidth in this route.
What does 100% reliability mean?
It compares all successfully received frames against all received frames. 100% reliability indicates that all the frames which we received were good. We don’t have any issue with physical link. If we have any issue with physical link, this value will be decrease.
Does EIGRP have equal cost?
For this destination we have two routes. Both routes have equal least bandwidth and cumulative delay. So naturally their cost will also be same. As we know EIGRP automatically load balance equal cost routes and these routes have equal cost. So they both make their way to routing table.
What is EIGRP wide metrics?
EIGRP includes support for a second set of metrics, known as wide metrics, that addresses the issue of scalability with higher-capacity interfaces. The original formula referenced in Figure 2-6 is known as EIGRP classic metrics.
What is EIGRP able to detect?
EIGRP is able to detect when peering with a router is using classic metrics, and it unscales the metric to the formula in Figure 2-13.
What is EIGRP load balancing?
EIGRP supports unequal-cost load balancing, which allows installation of both successor routes and feasible successors into the EIGRP RIB. To use unequal-cost load balancing with EIGRP, change EIGRP’s variance multiplier. The EIGRP variance value is the feasible distance (FD) for a route multiplied by the EIGRP variance multiplier. Any feasible successor’s FD with a metric below the EIGRP variance value is installed into the RIB. EIGRP installs multiple routes where the FD for the routes is less than the EIGRP multiplier value up to the maximum number of ECMP routes, as discussed earlier.
What is the purpose of K values in EIGRP?
To ensure consistent routing logic in an EIGRP autonomous system , the K values must match between EIGRP neighbors to form an adjacency and exchange routes. The K values are included as part of the EIGRP hello packet. The K values are displayed with the show ip protocols command, as demonstrated with the sample topology in Example 2-13. Notice that both routers are using the default K values, with R1 using classic metrics and R2 using wide metrics.
What is metric calculation?
Metric calculation is a critical component for any routing protocol. EIGRP uses multiple factors to calculate the metric for a path. Metric calculation uses bandwidth and delay by default but can include interface load and reliability, too. The formula shown in Figure 2-6 illustrates the EIGRP classic metric formula.
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What is EIGRP?
Enhanced Interior Gateway Routing Protocol is an advanced distance vector routing protocol based on the principles of the Interior Gateway Routing Protocol (IGRP). It has a unique characteristic that improves the operational ability and fast converging rate. It can determine the shortest path distance vector, and it works on the principle of Interior Gateway Routing Protocol, a classless routing protocol. It uses metrics like bandwidth, load and delays to calculate the shortest optimal network route. It is a technologically, more advanced distance vector-based routing protocol. To exchange information using EIGRP, first and foremost, the routers need to become neighbors to EIGRP, then EIGRP uses the multicast address to share the information.
What is EIGRP protocol?
It is a technologically, more advanced distance vector-based routing protocol. To exchange information using EIGRP, first and foremost, the routers need to become neighbors to EIGRP, then EIGRP uses the multicast address to share the information. Start Your Free Software Development Course. Web development, programming languages, Software testing & ...
What is EIGRP in Cisco routers?
Enhanced Interior Gateway Routing Protocol or EIGRP automates the routing decisions and configurations in computer networking. Cisco designed the protocol and is available only on Cisco routers. Minimum bandwidth is used from the source to destination, and the delay is measured using metrics of the network. This is an advanced protocol to measure the distance and uses both link servicing and distance routing. Hence it is called a hybrid protocol. It transitions well with IPv6 and has the support of IPv4 as well. This is a classless routing technique. Two routers are connected, and the network is shared in EIGRP.
What is enhanced interior gateway routing protocol?
Enhanced Interior Gateway Routing Protocol underlying logic is based on the concept of an autonomous system. In a system where each router should become neighbors to EIGRP and each system tagged as neighbors under Enhanced Interior, Gateway Routing Protocol will have the same system number configured.
What is EIGRP load balancing?
EIGRP performs load balancing over the equal-cost path and un-equal cost path. To perform the functions of EIGRP, it creates three tables which are: Following represents the ideology and concepts behind the three major tables: 1.
What is a reply packet?
Reply: Reply packets respond to a query that indicates the originator router that it does not need to go into an Active state as reliable successors for the destination network. Replies are sent when destinations go into an Active state. For the reply packet, an acknowledgment is sent.
Can EIGRP be used with Cisco?
EIGRP routing protocol can be accessible with the CISCO network devices.
