Категории: Все - topology - metrics

по emanresu emanresu 14 лет назад

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EIGRP

EIGRP, or Enhanced Interior Gateway Routing Protocol, is a Cisco-proprietary distance vector routing protocol designed to facilitate efficient routing within an autonomous system. It primarily uses the DUAL algorithm to calculate the least cost loop-free routes and feasible successors, ensuring backup routes are in place.

EIGRP

EIGRP

Metric

concepts
route distance
feasible condition

matched by

feasible sucessors

AD less than the FD of the current successor route

next-hop router for a backup path

successor

up to 6 successors can exist if they have the same FD

installed in routing table

lowest FD

lowest cost

best route

The lower the better
formula
default

k3=0

k2=1

k1=1

k2*delay/(k1*bandwidth+k3*reliability)
parameters
delay
reliability

0-255

bandwidth

Tables

Routing
(Externas) D EX

Administrative Distance = 170

i.e IGRP

Topology
includes feasible successors
Neighbor
interface
next-hop

Comparison with other Routing Protocols

Differences with RIP
higher bandwidth utilization
slow convergence

holddown timer

No backup routes
Periodic updates

EIGRP has

bounded

only send to who needs it

partial

only send what changes

packets

Hello
Ethernet

multicast

commands

verification
show ip protocols
show ip eigrp topology

show routes that match feasible condition

backup route

all-links

you can see all the routes

routes that NOT match feasible condition

routes that match feasible condition

configuration
network

interfaces matching network addr and wildcard

will appear in routing table

will send eigrp updates

router eigrp

MUST be equal in every router running eigrp on the network

Not related with AS number

1-65536

Characteristics

partial triggered updates
Subtema
updates are sent only when the path or the metric changes for a route
routes are automatically summarized at the major network number boundary
classless
Cisco-proprietary
Network protocols supported
AppleTalk
IPX
IP
Transport Protocol
RTP

Only IP

guaranteed ordered delivery and reception of EIGRP packets to all neighbors

Reliable Transport Protocol

load-balance between 4 unequal cost routes
Distance Vector Routing Protocol
Enhaced Interior Gateway Protocol

Routing Algorithm

DUAL
feasible distance (FD)

AD+cost between the local router and the next-hop router

advertised distance (AD)

cost between the next-hop router and the destination

calculates backup routes

feasible successor

calculates least cost loop-free routes