CCNA Study Notes (v)--Dynamic routing Protocol (EIGRP)

After learning rip, we know some basic routing protocols for routing, and now let's get to know a private protocol for Cisco: EIGRP

EIGRP Routing Protocol

(also known as Enhanced Internal Gateway Protocol Enhanced Interior Gateway Protocol)

It is a Cisco private dynamic routing protocol that combines the distance vector with the link state protocol, which can only be applied to Cisco devices above. EIGRP is not available if you have devices that use other vendors in your network.

1, the characteristics of EIGRP:

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fast convergence and reduced bandwidth consumption. (using the dual diffusion update algorithm, the routing backup update, when the S route is not available, quickly switch to FS, so as to achieve rapid convergence effect.) ）

100% no loop. (in the same autonomous system, EIGRP uses the dual algorithm, 100% guarantees no loops.) ）

use multicast or unicast to update routes. (use multicast 224.0.0.10 or unicast for routing updates to reduce bandwidth consumption)

increase the network size. (RIP Max 15 hops, ERGRP 255 hops, IGRP 224 hops, other defaults are 100 hops)

support three Layer network protocol. (Support IP, IPX, etc.)

support for VLSM and discontinuous networks. (RIP and IGRP not supported)

triggers the update. (Query Package Update routing table is sent when routing changes, using incremental update)

no class routing protocol. (can be divided into subnets, the aggregation of sub-networks)

Advanced Vector Protocol. (with distance vector attribute, with Link State Protocol feature)

The only support for a non-equivalent load-balanced routing protocol.

multiple EIGRP processes are supported on the same device.

2. Measure value (Metric):(dual algorithm: Used to calculate the best non-loop path and alternate path)

RIP: is to use the hop count as the measure value, select the destination network to reach the lowest hop number of routes to send data.

EIGRP is computed in the following ways:

Bandwidth (bandwidth): The minimum bandwidth on the link.

Delay: The value of the part delay on the link.

Load (Loading): The maximum load value on the link.

Reliability (Reliability): Minimum value of reliability on the link.

Maximum transmission order (MTU): The minimum value in the link.

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3. Several concepts:

A, feasible distance (feasible distance): The minimum distance value to reach a destination network.

B, the notification distance (advertise distance): The neighboring router advertises its own to reach a destination network minimum value.

C, feasible conditions (feasible condistioN): The advertised distance is less than the feasible distance.

D, successor (successor): refers to the route from the current route to the destination router path optimal.

A successor must meet two conditions:

1, it arrives at the destination router has the lowest measure value.

2. It is not part of the routing loop.

First condition: You can select the router with the lowest metric by comparing the minimum path metric that learns from all neighboring routers to reach the destination route.

Second condition: can be guaranteed by FC feasible conditions.

If there are multiple router metrics that go to the same destination, there will be multiple successors to achieve load balancing.

E, feasible successor (feasible successor):

In addition to the minimum measure path, a fallback path to each destination is stored in the topology table.

To become a post-secondary router, the advertised distance of the next hop router must be less than the feasible distance of the current route, i.e.:ad< FD. A feasible successor route must be closer to the destination than the current router, but because it is not a minimum metric on duty, it is not stored in the routing table, but is stored in the topology table.

As a successor, there are many paths to the same destination, so there are several possible successors.

4. EIGRP Routing Status:

1, passive state/passive Routing (passive State): is a status that currently has the correct route to the destination. When the router loses S (successor), there is a FS (feasible successor), or another S (successor) is found, the route enters the passive state and is an available route.

2. Active state/Active (Active): when S (successor) is lost, but there is no FS (feasible successor), it enters active state to search for S (successor), which is an unavailable route. When a route is active, the router sends a query to the neighbor looking for an available route to the destination.

3. Neighbor Relationship: EIGRP establishes a neighbor relationship by sending a Hello packet. In the low-band link, the Hello packet is sent at a interval of 60 seconds, if at a high-speed link, the delivery time of the Hello packet is 5 seconds, if not received in a period of time the neighbor sends the Hello packet, then resets the neighbor relationship. While waiting for the Hello packet, we call it hold time. This time is generally 3 times times the hello time. (Note: EIGRP establishes a neighbor relationship condition: K-value & Autonomous system number to be consistent, can be viewed through the SH IP eigrp neighbor)

5. Five types of EIGRP packages:

1, Hello Package: Establish and maintain the neighboring relationship, multicast address: 224.0.0.10

2. Update package:

A, the new neighbor relationship, you need to send the update package, unicast packets, the only time to send the entire routing table.

B, the topology table changes or receive the outgoing update package, send multicast packets

3, Query package: When the Discovery network path is not reached, send a query packet, sent multicast packets.

4. Reply Package: Reply package When the query packet is received, send multicast package.

5. Confirm Package: Unicast packet, acknowledgment of update/query/reply package (ACK).

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6. The working process of EIGRP:

1. Send Hello packet, find neighbor, establish neighbor table.

2, Exchange routing information, establish a topology table.

3. Run the dual algorithm to form the routing table.

7. EIGRP Routing Maintenance:

1, after convergence, the topology has not changed, with the Hello packet to maintain the neighbor relationship.

2. When a new route is found, the update packet is sent, and when Discovery S (successor) is lost, FS (feasible successor) immediately becomes S (successor) fast convergence, if there is no FS (feasible successor), Send query package queries.

3, when the topology is stable, the route status is passive, indicating that the route is available. When S (successor) is lost, the route fails, FS (feasible successor) becomes immediately S (successor), and the route becomes the passive state again. If there is no FS (feasible successor), the route becomes active (active), and the query packet is sent to all neighbors while the active timer starts.

8. Three sheets of EIGRP:

1. Neighbor Table (neighbor table): a route that establishes a neighbor relationship with the route and is connected directly.

2. Topology table (Topology table): The store contains all routing entries that are learned from all routes and arrive at the destination.

3. routing table (routing table): The route entry that stores the best path.

Take the topology as an example:

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We mainly look at the R2 to reach the destination network 2.2.2.2 three tables.

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From, we can see:

The IP addresses of the routers adjacent to the R2 are: 192.168.12.1 192.168.23.3

The R2 S0/1 S0/2 two interfaces are connected to the above two routers respectively.

At the same time, if a few EIGRP processes are running on the current route, we need to use the command when we look up EIGRP's neighbors:

Show IP eigrp neighbor>>>>> This is how you view only when you run an EIGRP process.

Show ip eigrp Neighbor >>>>> This is a lookup for the neighbor as number 100.

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===========================================================

Experiment:

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1. Basic configuration:

====================================================

R1 (config) #no IP domain lo

R1 (config) #lin Co 0

R1 (config-line) #logg sy

R1 (Config-line) #exec-T 0 0

----------------------------------------------------

R1 (config-line) #lin vty 0 4

R1 (config-line) #pass hznethome

R1 (Config-line) #login

----------------------------------------------------

R1 (config) #int Lo 0

R1 (config-if) #ip Add 1.1.1.1 255.255.255.0

R1 (config-if) #no sh

----------------------------------------------------

R1 (config-if) #int s0/0

R1 (config-if) #ip add 192.168.12.1 255.255.255.0

R1 (config-if) #no sh

----------------------------------------------------

R1 (config-if) #int S0/1

R1 (config-if) #ip add 192.168.14.1 255.255.255.0

R1 (config-if) #no sh

====================================================

R2 (config) #no IP domain lo

R2 (config) #lin Co 0

R2 (config-line) #logg sy

R2 (Config-line) #exec-T 0 0

R2 (config-line) #lin vty 0 4

R2 (config-line) #pass hznethome

R2 (Config-line) #login

----------------------------------------------------

R2 (config-line) #int Lo 0

R2 (config-if) #ip add 2.2.2.2 255.255.255.0

R2 (config-if) #no sh

----------------------------------------------------

R2 (config-if) #int S0/1

R2 (config-if) #ip add 192.168.12.2 255.255.255.0

R2 (config-if) #no sh

----------------------------------------------------

R2 (config-if) #int S0/2

R2 (config-if) #ip add 192.168.23.2 255.255.255.0

R2 (config-if) #no sh

=====================================================

R3 (config) #no IP domain lo

R3 (config) #lin Co 0

R3 (config-line) #logg sy

R3 (Config-line) #exec-T 0 0

R3 (config-line) #lin vty 0 4

R3 (config-line) #pass hznethome

R3 (Config-line) #login

----------------------------------------------------

R3 (config-line) #int Lo 0

R3 (config-if) #ip add 3.3.3.3 255.255.255.0

R3 (config-if) #no sh

----------------------------------------------------

R3 (config-if) #int S0/3

R3 (config-if) #ip add 192.168.23.3 255.255.255.0

R3 (config-if) #no sh

----------------------------------------------------

R3 (config-if) #int S0/2

R3 (config-if) #ip add 192.168.34.3 255.255.255.0

R3 (config-if) #no sh

=====================================================

R4 (config) #no IP domain lo

R4 (config) #lin Co 0

R4 (config-line) #logg sy

R4 (Config-line) #exec-T 0 0

R4 (config-line) #lin vty 0 4

R4 (config-line) #pass hznethome

R4 (Config-line) #login

----------------------------------------------------

R4 (config-line) #int Lo 0

R4 (config-if) #ip add 4.4.4.4 255.255.255.0

R4 (config-if) #no sh

----------------------------------------------------

R4 (config-if) #int S0/1

R4 (config-if) #ip add 192.168.14.4 255.255.255.0

R4 (config-if) #no sh

----------------------------------------------------

R4 (config) #int S0/2

R4 (config-if) #ip add 192.168.34.4 255.255.255.0

R4 (config-if) #no sh

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2, the configuration of EIGRP protocol:

R1 (config) #router EIGRP 100

R1 (config-router) #net 1.0.0.0 0.0.0.255

R1 (config-router) #net 192.168.14.0 0.0.0.255

R1 (config-router) #net 192.168.23.0 0.0.0.255

R1 (Config-router) #end

----------------------------------------------------

R2 (config) #router EIGRP 100

R2 (config-router) #net 2.0.0.0 0.0.0.255

R2 (config-router) #net 192.168.12.0 0.0.0.255

R2 (config-router) #net 192.168.23.0 0.0.0.255

R2 (Config-router) #end

----------------------------------------------------

R3 (config) #router EIGRP 100

R3 (config-router) #net 3.0.0.0 0.0.0.255

R3 (config-router) #net 192.168.23.0 0.0.0.255

R3 (config-router) #net 192.168.34.0 0.0.0.255

R3 (Config-router) #end

----------------------------------------------------

R4 (config) #router EIGRP 100

R4 (config-router) #net 4.0.0.0 0.0.0.255

R4 (config-router) #net 192.168.14.0 0.0.0.255

R4 (config-router) #net 192.168.34.0 0.0.0.255

R4 (Config-router) #end

=====================================================

Good sleepy, do not write, the experiment just did the basic experiment, other experiments later send up!!!

Good luck to you all!!!

If you want to experiment with this chapter, please download the attachment, thank you!

This article is from the "Last Bus" blog, so be sure to keep this source http://hznethome.blog.51cto.com/722914/1584085

CCNA Study Notes (v)--Dynamic routing Protocol (EIGRP)