packetlife.net
by Jeremy Stretch v2.1
EIGRP
Protocol Header
Type
Attributes
Algorithm
Internal AD
External AD
Distance Vector
DUAL
90
170
Summary AD
Standard
Protocols
Transport
5
Cisco proprietary
IP, IPX, Appletalk
IP/88
Version Opcode Checksum
8 16 24 32
Flags
Sequence Number
Acknowledgment Number
Autonomous System Number
Type Length
Value
Authentication
Multicast IP
Hello Timers
Hold Timers
MD5
224.0.0.10
5/60
15/180
Metric Formula
256 * (K
1
* bw + + K
3
* delay) *
K
2
* bw
256 - load
K
5
rel + K
4
· bw = 10
7
/ minimum path bandwidth in kbps
· delay = interface delay in µsecs / 10
EIGRP Configuration
! Enable EIGRP
router eigrp <ASN>
! Add networks to advertise
network <IP address> <wildcard mask>
! Configure K values to manipulate metric formula
metric weights 0 <k1> <k2> <k3> <k4> <k5>
! Disable automatic route summarization
no auto-summary
! Designate passive interfaces
passive-interface (<interface> | default)
! Enable stub routing
eigrp stub [receive-only | connected | static | summary]
! Statically identify neighoring routers
neighbor <IP address> <interface>
Protocol Configuration
! Set maximum bandwidth EIGRP can consume
ip bandwidth-percent eigrp <AS> <percentage>
! Configure manual summarization of outbound routes
ip summary-address eigrp <AS> <IP address> <mask> [<AD>]
! Enable MD5 authentication
ip authentication mode eigrp <AS> md5
ip authentication key-chain eigrp <AS> <key-chain>
! Configure hello and hold timers
ip hello-interval eigrp <AS> <seconds>
ip hold-time eigrp <AS> <seconds>
! Disable split horizon for EIGRP
no ip split-horizon eigrp <AS>
Interface Configuration
K Defaults Packet Types
K
1
1
K
2
0
K
3
1
K
4
0
K
5
0
1Update
3Query
4Reply
5Hello
8Acknowledge
Terminology
Feasible Distance
The distance advertised by a neighbor plus the cost
to get to that neighbor
Reported Distance
The metric for a route advertised by a neighbor
Stuck In Active (SIA)
The condition when a route becomes unreachable
and not all queries for it are answered; adjacencies
with unresponsive neighbors are reset
Passive Interface
An interface which does not participate in EIGRP but
whose network is advertised
Stub Router
A router which advertises only a subset of routes,
and is omitted from the route query process
Troubleshooting
show ip eigrp interfaces
show ip eigrp neighbors
show ip eigrp topology
show ip eigrp traffic
clear ip eigrp neighbors
debug ip eigrp [packet | neighbors]
