Course synopsis is the most widely recognized tuning technique for EIGRP. It permits a switch to bunch numerous organizations and publicizes them as one enormous gathering utilizing a solitary, summed up course. The capacity to sum up courses is vital because of the quick development of organizations.

Course outline decreases the quantity of courses in the bigger organization with numerous subnets. The rundown likewise decreases the traffic utilized for directing updates. We can sum up the courses via programmed synopsis and manual outline. The auto rundown highlight is empowered of course on EIGRP. By utilizing default auto outline, courses are summed up to classful location at network limits in the directing updates.

EIGRP will check for any subnets that fall inside the scope of your organization order and whenever found, it will publicize the classful A, B or C organization to its neighbors. The default auto-synopsis just sums up courses from subnets on its connection points, not the courses gained from different switches.

Figure 1 delineates the course of course rundown. Switches R1, R2 and R3 are designed involving EIGRP for IPv4 with programmed synopsis. R1 has four subnets in its steering table:,, and These subnets are completely viewed as the piece of a bigger class An organization, Since programmed rundown is empowered on switch R1, so it sums up the all subnets as a solitary organization of Synopsis diminishes the quantity of directing updates sent and the quantity of sections in R2’s IPv4 steering table. Traffic bound for the three subnets, and goes across the one normal way. R2 never keep up with courses to individual subnets.

Designing EIGRP Automatic outline

Prior to Cisco IOS Release 15.0(1)M and 12.2(33) programmed synopsis was empowered of course, after the arrival of these IOS forms the programmed rundown is impaired naturally. So in the most recent IOS discharge, we ought to arrange the programmed rundown.

Figure 2 represents the result of the “show ip conventions” order on R1. The figure represents that the programmed outline is crippled on R1. This is on the grounds that the switch running IOS Version 15.1(4)M4 subsequently, programmed outline is crippled

Figure 3 shows the current steering table for R2. R2 is the edge switch for R1 and R2. Notice that the EIGRP IPv4 steering table for R2 contains the organizations as a whole and subnets inside the EIGRP directing area. We can empower programmed synopsis for EIGRP utilizing the “auto-rundown” order in switch setup mode.

R1(config)# switch eigrp 100

R1(config-router)# auto-outline

For programmed outline on all switches utilize similar orders. “100” is the independent framework number of EIGRP area. We can refute the programmed rundown utilizing the “no auto-synopsis” order in switch design mode.

Checking Auto-Summary

We can check the auto-synopsis setup by utilizing the order “show ip conventions”. Figure 4 delineates the result of this order empowering the auto-rundown on R1.

We can inspect and confirm the synopsis from R2’s steering table. Utilizing the “show ip course eigrp” order, we can show the steering table of R2 for EIGRP area. Figure 5 shows the steering table of R2 after auto-synopsis design.

As shown in Figure 3, R1 sums up the and subnet. It advances the summed up address of to its neighbors on its Serial 0/0/0 and GigabitEthernet 0/0 points of interaction. Since R1 doesn’t have any EIGRP neighbors on its GigabitEthernet 0/0 point of interaction, the summed up directing update is just gotten by R2.

Confirming Auto-Summary from Topology Table

In Figure 6, switches R1 will send R2 a summed up EIGRP directing update of Steering tables for R1, R2, and R3 contain subnets of the organization; thus, all switches send the rundown notice across an alternate significant organization.

We can confirm the arrangement of the auto-rundown on R2 and R3 geography table. This will check that R2 and R3 have gotten the rundown course. We can utilize the all-joins boundary with the “show ip eigrp geography” to show every single got update.

Invalid Interface

Figure 5 shows the directing table for R2. The featured sections are utilizing a leave point of interaction of Null0. EIGRP consequently adds an outline course to Null0 for two classful organizations and It is an IOS virtual point of interaction that is a course to no place, otherwise called “the piece pail.” Packets that coordinate a course with a Null0 leave connection point are disposed of.

The Null0 rundown course forestalls steering circles for objections that are coordinated into the outline however don’t exist in the directing table. EIGRP for IPv4 consequently remembers a Null0 outline course for the accompanying circumstances:

  • On account of one subnet that was learned by means of EIGRP.
  • On account of at least two organization EIGRP switch design mode orders.
  • Programmed rundown is empowered.

Notice – Automatic outline isn’t accessible for IPv6, on the grounds that classful tending to doesn’t exist in IPv6.