cnap_3_03_eigrp

7/27/2019 cnap_3_03_EIGRP

1/57

CNAP Semester 3: Switching

Basics and Intermediate Routing

Module 3

EIGRP

7/27/2019 cnap_3_03_EIGRP

2/57

Objectives

Describe the eight-step process for generaltroubleshooting

Apply a logical process to routing

troubleshooting

Troubleshoot a RIP routing process using show

and debug commands

Troubleshoot an IGRP routing process using

show and debug commands Troubleshoot an EIGRP routing process using

show and debug commands

Troubleshoot an OSPF routing process usingshow and debu commands

7/27/2019 cnap_3_03_EIGRP

3/57

Table of Content

1 EIGRP Concepts

2 EIGRP Configuration

3 Troubleshooting Routing Protocols

7/27/2019 cnap_3_03_EIGRP

4/57

Objectives

Describe the differences between EIGRP and

IGRP

Describe the key concepts, technologies, and

data structures of EIGRP Understand EIGRP convergence and the basic

operation of the Diffusing Update Algorithm

(DUAL)

Perform a basic EIGRP configuration

Configure EIGRP route summarization

Describe the processes used by EIGRP to build

and maintain routing tables

7/27/2019 cnap_3_03_EIGRP

5/57

EIGRP CONCEPTS

7/27/2019 cnap_3_03_EIGRP

6/57

EIGRP Overview

Cisco released EIGRP in 1994 as a scalable,

improved version of its proprietary distance

vector routing protocol, IGRP.

Unlike IGRP, which is a classful routing protocol,EIGRP supports CIDR and VLSM.

Hybrid routing protocol

Fast convergence times Multiple network-layer protocols supported

Reduced bandwidth usage

Easy to configure

7/27/2019 cnap_3_03_EIGRP

7/57

EIGRP and IGRP compatibility

Default: k1 = 1, k2 = 0, k3 = 1, k4 = 0, k5 = 0.

Metric = Bandwidth + Delay

EIGRP scales IGRP's metric by a factor of256. Because

EIGRP uses a metric that is 32 bits long (IGRP 24-bit):

Bandwidth for IGRP = (10.000.000 / bandwidth)

Bandwidth for EIGRP = (10.000.000 / bandwidth)*256 Delay for IGRP = (delay/10)

Delay for EIGRP = (delay/10) * 256

k1xBW +k2xBW

256 Load+ k3xDelayMetric =

7/27/2019 cnap_3_03_EIGRP

8/57

EIGRP and IGRP compatibility

192.168.1.0/24

RTC

EIGRP 2446IGRP 2446

172.16.1.0/24

10.1.1.0/24

EIGRP and IGRP automatically redistribute routesbetween autonomous systems with sameautonomous system (AS) number.

IGRP has a maximum hop count of 255. EIGRP has

a maximum hop count limit of 224.

RTD

RTA

RTB

7/27/2019 cnap_3_03_EIGRP

9/57

Neighbor TableAppleTalkDestination Next Hop

Router

Neighbor TableIPXDestination Next Hop

Router

Neighbor TableIPNext-Hop InterfaceRouter

EIGRP concepts and terminology

7/27/2019 cnap_3_03_EIGRP

10/57


Router


Router


Topology TableAppleTalkDestination 1 Next Router 1/CostDestination 1 Next Router 1/Cost

Topology TableIPXDestination 1 Next Router 1/CostDestination 1 Next Router 1/Cost

Topology TableIPDestination 1


7/27/2019 cnap_3_03_EIGRP

11/57



Topology TableIPDestination 1

Routing TableAppleTalkDestination 1 Next Router XDestination 1 Next Router X

Routing TableIPXDestination 1 Next Router XDestination 1 Next Router X

Routing TableIPDestination 1


Router


Router



7/27/2019 cnap_3_03_EIGRP

12/57



Topology TableIPDestination 1 Successor



Routing TableIPDestination 1 Successor


Router


Router



7/27/2019 cnap_3_03_EIGRP

13/57



Topology TableIPDestination 1 SuccessorDestination 1 Feasible Successor



Routing TableIPDestination 1 Successor


Router


Router


EIGRP concepts and

terminology

7/27/2019 cnap_3_03_EIGRP

14/57

Network Z

EIGRP Successors and

Feasible successor

RTA

RTB

I have a routeto Z, with ametric of 5

RTB is successor to Net Z

7/27/2019 cnap_3_03_EIGRP

15/57

Network Z


Feasible successor

RTA

RTB

RTC



RTB is successor to Net ZRTB is successor to Net Z

7/27/2019 cnap_3_03_EIGRP

16/57

Network Z


Feasible successor

RTA

RTX

RTB

RTC

RTY




RTB is successor to Net ZRTC is successor to Net ZRTX is feasible successorto Net Z

7/27/2019 cnap_3_03_EIGRP

17/57

EIGRP design

EIGRP's advantages over simple distance-vector protocols :

Rapid convergence (because of use DiffusingUpdate Algorithm - DUAL)

Efficient use of bandwidth

Partial, bounded (incremental) updates

Minimal consumption (tiu dng) ofbandwidth when the network is stable withsmall hello packets

Support for VLSM and CIDR

Multiple network-layer support andIndependence from routed protocols

7/27/2019 cnap_3_03_EIGRP

18/57

EIGRP technologies

Many new technologies are improvement

in operating efficiency, speed of

convergence, or functionality relative to

others routing protocols.

Four categories:

Neighbor discovery and recovery

Reliable Transport Protocol (RTP)

DUAL finite-state machine algorithm

Protocol-dependent modules (PDM)

7/27/2019 cnap_3_03_EIGRP

19/57

Neighbor discovery and

recovery EIGRP routers establish adjacencies with

neighbor routers by using small hello

packets

On IP networks, EIGRP routers send

hellos to the multicast IP address

224.0.0.10

RTA#show ip eigrp neighborsIP-EIGRP neighbors for process 400

H Address Interface Hold Uptime SRTT RTO Q Seq

(sec) (ms) Cnt Num

1 172.68.2.2 To0 13 02:15:30 8 200 0 9

0 172.68.16.2 Se1 10 02:38:29 29 200 0 6

13 02:15:30

10 02:38:29

Bandwidth Example link Default hellointerval

Default holdtimes

T1 or less Multipoint

frame relay,

ISDN

60 seconds 180 seconds

Greater than T1 Ethernet, T1 5 seconds 15 seconds

7/27/2019 cnap_3_03_EIGRP

20/57

Neighbor discovery and

recovery By forming adjacencies, EIGRP routers

do:

Dynamically learn of new routes that join

their network

Identify routers that become either

unreachable or inoperable

Rediscover routers that had previously

been unreachable

7/27/2019 cnap_3_03_EIGRP

21/57

I am router A, who is on the link?Hello

A B

1

Initial Route Discovery

Here is my complete routing information. Update2

Thanks for theinformation!

Ack3Topology

Table

4

Here is my complete route information.Update5

Converged

Thanks for the information! 6

7/27/2019 cnap_3_03_EIGRP

22/57

Reliable Transport Protocol

(RTP) EIGRP uses RTP as its own proprietary transport-layer

protocol, that can guarantee ordered delivery of routing

information to all neighbors.

EIGRP can call on RTP to provide reliable or unreliable

service as the situation warrants.

Reliable delivery of other routing information can actually

speed convergence, because EIGRP routers are not

waiting for a timer to expire before they retransmit.

With RTP, EIGRP can multicast and unicast to different

peers simultaneously, which allows for maximum

efficiency.

7/27/2019 cnap_3_03_EIGRP

23/57


(RTP) EIGRP reliable packets are packets that

requires explicit acknowledgement:

Update: Send routing updates

Query: Ask neighbors about routing

information

Reply: Response to query about routing

information

EIGRP unreliable packets are packets that

do not require explicit acknowledgement:

7/27/2019 cnap_3_03_EIGRP

24/57

Diffusing Update Algorithm (DUAL) is EIGRP's

route-calculation engine.

Finite-state machine

Tracks all routes advertised by neighbors

Select loop-free path using a successor and

remember any feasible successors

If successor lost, use feasible successor If no feasible successor, query neighbors and

recomputed new successor

DUAL finite-state machine

algorithm

7/27/2019 cnap_3_03_EIGRP

25/57

DUALDiscovery route

A B

CRouter B information

Neighbor TableIP

Router C information

Router B information

Topology TableIP

Router C information

Successor (primary route)Feasible successor

Routing TableIP

Successor (primary route)

DUAL?

7/27/2019 cnap_3_03_EIGRP

26/57

E EIGRP FD RD Topology(a) 3 (fd)

via D 3 2 (Successor)via C 4 3

D EIGRP FD RD Topology(a) 2 (fd)

via B 2 1 (Successor)via C 5 3

C EIGRP FD RD Topology(a) 3 (fd)

via B 3 1 (Successor)via D 4 2 (fs)via E 4 3

(1)

(1)

(1)

(1)

(2)(2)

(a)

A

E

D

C

B

DUAL Example (Start)

7/27/2019 cnap_3_03_EIGRP

27/57

(1)

(1)

(1)

(1)

(2)(2)

(a)

A

E

D

C

B







X

DUAL Example (cont. )

7/27/2019 cnap_3_03_EIGRP

28/57

QQ

(1)

(1)

(1)

(2)(2)

(a)

A

E

D

C

B



D EIGRP FD RD Topology(a) **ACTIVE** -1 (fd)

via E (q)via C 5 3 (q)


via B 3 1 (Successor)via Dvia E 4 3


7/27/2019 cnap_3_03_EIGRP

29/57

R

Q

(1)

(1)

(1)

(2)(2)

(a)

A

E

D

C

B

E EIGRP FD RD Topology(a) **ACTIVE** -1 (fd)

via Dvia C 4 3 (q)


via E (q)via C 5 3


via B 3 1 (Successor)via D

via E 4 3


7/27/2019 cnap_3_03_EIGRP

30/57

R

(1)

(1)

(1)

(2)(2)

(a)

A

E

D

C

B


via C 4 3 (Successor)via D


via E (q)via C 5 3


via B 3 1 (Successor)via Dvia E


7/27/2019 cnap_3_03_EIGRP

31/57

R

(1)

(1)

(1)

(2)(2)

(a)

A

E

B




via C 5 3 (Successor)via E 5 4 (Successor)



D

C


7/27/2019 cnap_3_03_EIGRP

32/57

(1)

(1)

(1)

(1)

(2)(2)

(a)

A

E

D

C

B







DUAL Example (Start)

7/27/2019 cnap_3_03_EIGRP

33/57

(1)

(1)

(1)

(2)(2)

(a)

A

E

D

C

B




via C 5 3 (Successor)via E 5 4 (Successor)



DUAL Example (End)

7/27/2019 cnap_3_03_EIGRP

34/57

Protocol-dependent modules

(PDM) Support for routed protocols, such as IP, IPX, and AppleTalk,

is included in EIGRP through PDMs.

Easily adapt to new or revised routed protocols, such as IPv6,by adding protocol-dependent modules.

Each PDM is responsible for all functions related to its specificrouted protocol. The IP-EIGRP module is responsible for thefollowing:

Sending and receiving EIGRP packets that bear IP data

Notifying DUAL of new IP routing information that is

received Maintaining the results of DUAL routing decisions in the IP

routing table

Redistributing routing information that was learned byother IP-capable routing protocols

7/27/2019 cnap_3_03_EIGRP

35/57

CONFIGURING EIGRP

7/27/2019 cnap_3_03_EIGRP

36/57

For IP networks

1.router(config)# router eigrpautonomous-

system-number

AS much match all router inside AS

2.router(config-router)# networknetwork-

number

Network number only for connected

network

3.router(config-if)# bandwidthkilobits

Serial interface link use (if not Router take

default)

7/27/2019 cnap_3_03_EIGRP

37/57

For IP networks

7/27/2019 cnap_3_03_EIGRP

38/57

EIGRP summarization

Automatic

7/27/2019 cnap_3_03_EIGRP

39/57

Manual summarization Configurable on a per-interface basis in any

router within network

When summarization is configured on aninterface, the router immediate creates a route

pointing to null zero

Loop prevention mechanism

When the last specific route of the summarygoes away, the summary is deleted

The minimum metric of the specific routes is

used as the metric of the summary route

EIGRP SummarizationManual

7/27/2019 cnap_3_03_EIGRP

40/57

(config-router)#

no auto-summary

Turns off autosummarization for theEIGRP process

(config-if)#

ip summary-address eigrp

Creates a summary address to be generatedby this interface

EIGRP SummarizationManual

7/27/2019 cnap_3_03_EIGRP

41/57

Summarizing EIGRP routes

Manual

RTC(config)#router eigrp 2446RTC(config-router)#no auto-summaryRTC(config-router)#exitRTC(config)#interface serial0

RTC(config-if)#ip summary-address eigrp 2446 2.1.0.0 255.255.0.0

V if EIGRP ith Sh

7/27/2019 cnap_3_03_EIGRP

42/57

Verify EIGRP with Show

commandCommand DescriptionShow ip eigrp neighbors

[int type] [details]

Display EIGRP neighbor table

Show ip eigrp

interfaces [int type]

[as-number][details]

Displays EIGRP statistics and status information

Show ip eigrp topology

[as-number][ [ip-add]

mask ]

Display the EIGRP topology table, use the show ip

eigrp topology EXEC command. Also used to

determine DUAL states & debug possible DUAL

problems.

Show ip eigrp topology

[active | pending |

zero-successor]

Depending on keywork is used. Display all routes

in the topology table that are either active, pending

or without successor

Show ip eigrp all-links Display all routes not just FC in EIGRP topology

Show ip eigrp traffic

[as-number]

Display the number of EIGRP packets send and

received.

V if EIGRP ith D b

7/27/2019 cnap_3_03_EIGRP

43/57

Verify EIGRP with Debug

commandCommand DescriptionDebug eigrp fsm This command helps you observe EIGRP FS activuty

and to determine whether route updates are being

installed and deleted by the routing process

debug eigrp packet Displays all types of EIGRP packets, both sent and

received

debug eigrp neighbor Displays the EIGRP neighbor interaction

debug ip eigrp route Displays advertisements and changes EIGRP makes

to the routing table

debug ip eigrp

summary

Displays a brief report of the EIGRP routing activity

show ip eigrp events Displays the different categories of EIGRP activity,

including route calculations

7/27/2019 cnap_3_03_EIGRP

44/57

TROUBLESHOOTING

ROUTING PROTOCOLS

T bl h ti T l d

7/27/2019 cnap_3_03_EIGRP

45/57

Troubleshooting Tools and

Utilities

T bl h ti RIP

7/27/2019 cnap_3_03_EIGRP

46/57

Troubleshooting RIP

configuration If the RIP routes are not being advertised,

check the following:

Layer 1 or Layer 2 connectivity issues

exist.

VLSM subnetting is configured. VLSM

subnetting cannot be used with RIP v1.

Mismatched RIP v1 and RIP v2 routing

configurations exist.

Network statements are missing or

incorrectl assi ned.

U h i t l

7/27/2019 cnap_3_03_EIGRP

47/57

Use show ip protocols

command

7/27/2019 cnap_3_03_EIGRP

48/57

Use debug ip rip command

3d08h: RIP: bad version 128 from 160.89.80.43

7/27/2019 cnap_3_03_EIGRP

49/57

T bl h ti IGRP

7/27/2019 cnap_3_03_EIGRP

50/57

Troubleshooting IGRP

configuration (cont.) To view IGRP debugging information, use

the following commands:

debug ip igrp transactions [host ip

address] to view IGRP transactioninformation

debug ip igrp events [host ipaddress] to view routing updateinformation

To turn off debugging, use the no debugip igrp command.

T bl h ti EIGRP

7/27/2019 cnap_3_03_EIGRP

51/57

Troubleshooting EIGRP

configuration Some possible reasons why EIGRP may

not be working correctly are:

Layer 1 or Layer 2 connectivity issues

exist.

Autonomous system numbers on EIGRP

routers are mismatched.

The link may be congested or down.

The outgoing interface is down.

The advertised network interface is down.

Auto-summarization is enabled on routers

Use sho ip eigrp neighbors

7/27/2019 cnap_3_03_EIGRP

52/57

Use show ip eigrp neighbors

command One of the most common reasons for a

missing neighbor is a failure on the actual

link. Another possible cause of missing

neighbors is an expired holddown timer.RTA#show ip eigrp neighborsIP-EIGRP neighbors for process 400

H Address Interface Hold Uptime SRTT RTO Q Seq

(sec) (ms) Cnt Num

1 172.68.2.2 To0 13 02:15:30 8 200 0 9

0 172.68.16.2 Se1 10 02:38:29 29 200 0 6

13

10

should normally bea value between

10 and 15.

Troubleshooting OSPF

7/27/2019 cnap_3_03_EIGRP

53/57


configuration The majority of problems encountered with

OSPF relate to the formation of adjacencies andthe synchronization of the link-state databases.

The show ip ospf neighborcommand is usefulfor troubleshooting adjacency formation.

Use the debug ip ospf events privileged EXECcommand to display the following informationabout OSPF-related events:

Adjacencies

Flooding information

Designated router selection

Shortest path first (SPF) calculation


7/27/2019 cnap_3_03_EIGRP

54/57


configuration (cont.) If a router configured for OSPF routing is

not seeing an OSPF neighbor on anattached network, perform the following

tasks: Verify that both routers have been

configured with the same IP mask,OSPF hello interval, and OSPF dead

interval.

Verify that both neighbors are part of thesame area.

7/27/2019 cnap_3_03_EIGRP

55/57

Summary Cisco released EIGRP in 1994 as a scalable,improved version of its proprietary distance

vector routing protocol, IGRP.

EIGRP improves the convergence properties

and the operating efficiency significantly over

IGRP. EIGRP includes may new technologies.

These technologies fall into one of the

following foure categories: Neighbor discovery and recovery


DUAL finite-state machine algorithm

7/27/2019 cnap_3_03_EIGRP

56/57

Q&A

7/27/2019 cnap_3_03_EIGRP

57/57

cnap_3_03_eigrp

Documents