SEMESTER 2 Chapter 9
EIGRP
V 4.0
9.0.1
9.1.1
What features are found in
EIGRP that are not found in
other distance vector routing
protocols?
What type of protocol does
EIGRP act like?
What type of routing protocol is
EIGRP?
How is EIGRP similar to RIP
v2?
What protocol was the
precursor to EIGRP?
What are the metrics
composed of?
What algorithm was used in
IGRP?
What two things does EIDRP
not do?
What table does EIGRP
maintain that is separate from
the routing table?
What is included in the above
table?
Define loop-free.
What is the result of using
mechanisms to prevent routing
loops and count to infinity
problems in RIP and IGRP?
What does EIGRP use to solve
these problems?
9.1.2
9.1.2.2
What are the three
type/length/value types in
EIGRP?
What is the protocol field value
for EIGRP?
What is the destination ip
address?
What is the MAC address for
an EIGRP packet in a frame?
What are the four Opcodes for
Reliable Transport Protocol (RTP)
Bounded Updates
Diffusing Update Algorithm (DUAL)
Establishing Adjacencies
Neighbor and Topology Tables
Link-state
Distance Vector
EIGRP can operate with classful or classless routing
behavior
IGRP
bandwidth, delay, reliability, and load
the Bellman-Ford algorithm
EIGRP does not send periodic updates and route
entries do not age out.
Topology table
includes both the best path to a destination network
and any backup paths that DUAL has determined to be
loop-free
the neighbor does not have a route to the destination
network that passes through this router
Slow convergence
loop-free paths are achieved through a system of route
calculations (diffusing computations) that are
performed in a coordinated fashion among the routers
EIGRP Parameters, IP Internal Routes, and IP External
Routes
88
224.0.0.10
01-00-5E-00-00-0A
EIGRP Parameters, IP Internal Routes, and IP External
EIGRP?
What are the two factors that
EIGRP weights?
Define delay.
Define Bandwidth.
9.1.3
9.1.4
9.1.4.2
9.1.5
What is the minimum length for
a subnet mask in EIGRP?
What is added to the subnet
mask to reach the minimum
length?
What are the three protocols
does EIGRP support?
What does EIGRP use to be
able to support these
protocols?
What protocol does EIGRP use
to deliver and receive packets?
Why does EIGRP have to use
the above protocol?
What are the two methods of
delivery for RTP?
What is the difference between
the two methods of delivery?
What are the two methods that
RTP can send packets?
What are Hello packets used
for?
What are Update packets used
for?
When are Update packets
sent?
What are ACK packets used
for?
When are ACK packets used in
EIGRP?
What type of delivery method
does an ACK packet use?
What are QUERY and REPLY
packets used for?
What must happen before
EIGRP can exchange packets
between routers?
What is a Hello packet used
for?
Routes
Bandwidth and delay
the sum of delays from source to destination in units of
10 microseconds
the lowest configured bandwidth of any interface along
the route
24
Zeros
IP, IPX, and AppleTalk
protocol-dependent modules (PDM)
used by EIGRP for the delivery and reception of EIGRP
packets
EIGRP was designed as a Network layer independent
routing protocol; therefore, it cannot use the services of
UDP or TCP because IPX and Appletalk do not use
protocols from the TCP/IP protocol suite.
reliable delivery and unreliable delivery
Reliable requires acknowledgement of the packet
Unreliable does not require acknowledgement
Multicast and unicast
used by EIGRP to discover neighbors and to form
adjacencies with those neighbors
used by EIGRP to propagate routing information
Only when necessary
sent by EIGRP when reliable delivery is used
for EIGRP update, query, and reply packets
Unreliable delivery
used by DUAL when searching for networks and other
tasks
EIGRP must first discover its neighbors
EIGRP routers discover neighbors and establish
adjacencies with neighbor routers using the Hello
packet
How often are hello packets
sent?
How often are hellos packets
sent on multipoint
nonbroadcast multiaccess
networks (NBMA)?
What does an EIGERP router
assume if it continues to
receive hello packets from a
neighbor?
Define Holdtime.
9.1.6
What is the holdtime by
default?
What happens if the holdtime
expires?
Define partial.
Define bounded.
9.1.7
9.1.8
9.1.9
9.2.2
Why does EIGRP use partial
bounded updates?
What is the Diffusing Update
Algorithm (DUAL)?
What problem is associated
with DUAL recalculations?
What does DUAL do to avoid
recalculations?
Define Administrative Distance.
What are the two default
administrative distances for
EIGRP?
What is the administrative
distance for a summary route?
Can EIGRP be configured to
use authentication?
Define an Autonomous System.
Who is responsible for
assigning AS?
What is the length of an AS
number?
Who needs an autonomous
system number?
9.2.2.2
What does EIGRP use a
process ID for?
Every 5 seconds
Every 60 seconds
the neighbor and its routes remain viable
the maximum time the router should wait to receive the
next Hello before declaring that neighbor as
unreachable
3 time the hello interval
EIGRP will declare the route as down and DUAL will
search for a new path by sending out queries
the update only includes information about the route
changes
the propagation of partial updates sent only to those
routers that are affected by the change
To conserve bandwidth
the convergence algorithm used by EIGRP
Processor intensive
DUAL maintains a list of backup routes it has already
determined to be loop-free.
the trustworthiness (or preference) of the route source
90 for internal routes
170 for external routes
5
Yes
autonomous system (AS) is a collection of networks
under the administrative control of a single entity that
presents a common routing policy to the Internet
Internet Assigned Numbers Authority (IANA)
32-bits
Usually ISPs (Internet Service Providers), Internet
backbone providers, and large institutions connecting
to other entities that also have an AS number.
to represent an instance of their respective routing
protocol running on the router
9.2.3
9.2.4
9.2.4.2
9.2.5
What is the command to enable
EIGRP as the routing protocol?
Who chooses the autonomous
system number used in the
above command?
What is the range available for
autonomous system numbers?
What are the two functions that
the network command
provides?
What is used in EIGRP to limit
the number of interfaces within
a network that will be
advertised?
What is the inverse of a subnet
called?
What must be established
before any updates can be sent
or received?
Define the following entries in
the EIGRP neighbor table:
H column
Address
Interface
Hold
Uptime
SRTT
Queue Count
Sequence Number
If a ping is successful but the
router still does not see the
other router as a neighbor,
what else should be checked?
eigrp autonomous-system
System administrator
1 and 65535
Any interface on this router that matches the network
address in the network command will be enabled to
send and receive EIGRP updates.
This network (or subnet) will be included in EIGRP
routing updates.
Wildcard mask
Wildcard mask
Adjacencies
Lists the neighbors in the order they were learned.
The IP address of the neighbor.
The local interface on which this Hello packet was
received.
The current hold time. Whenever a Hello packet is
received, this value is reset to the maximum hold time
for that interface and then counts down to zero. If zero
is reached, the neighbor is considered "down".
Amount of time since this neighbor was added to the
neighbor table.
Smooth Round Trip Timer) and RTO (Retransmit
Interval) - Used by RTP to manage reliable EIGRP
packets. SRTT and RTO are discussed further in
CCNP courses.
Should always be zero. If more than zero, then EIGRP
packets are waiting to be sent. Queue count is
discussed further in CCNP courses.
Used to track updates, queries, and reply packets.
Sequence numbers are discussed further in CCNP
courses.
Are both routers configured with the same EIGRP
process ID?
Is the directly connected network included in the
EIGRP network statements?
Is the passive-interface command configured to
prevent EIGRP Hello packets on the interface?
9.2.6
9.2.6.2
9.3.1
9.3.1.2
9.3.2
9.3.2.2
9.3.2.3
9.3.3
9.3.4
9.3.4.2
9.4.1
What is the command to
disable automatic route
summarization?
What variably subnetted mean?
What happens if a packet
matches the parent route but
none of the child routes?
What are the two conditions
that must be met for EIGRP to
include a null0 summary route?
What happens to the summary
route when the no autosummary command is issued?
What are the metrics that
EIGRP can use?
no auto-summary
Use different subnet masks for subnets
It is discarded
There is at least one subnet that was learned via
EIGRP.
Automatic summarization is enabled.
It is removed
Bandwidth
Delay
Reliability
Load
Bandwidth
Delay
Show ip protocols
What two metrics are used by
default?
What command can be issued
to see the K values?
What command can be used to show interface
examine the actual values used
for bandwidth, delay, reliability,
and load in the computation of
the routing metric?
Define delay.
a measure of the time it takes for a packet to traverse a
route
Define reliability.
a measure of the probability that the link will fail or how
often the link has experienced errors
Define load.
the amount of traffic utilizing the link
Does the bandwidth command
no
change the actual speed of the
interface?
What is the multiplier used to
256
calculate EIGRP metric?
What bandwidth is used in
The slowest
calculating the EIGRP value
between two interfaces?
What is the reference value for 10,000,000
bandwidth in EIGRP?
How is delay calculated in
EIGRP uses the cumulative sum of delay metrics of all
EIGRP?
of the outgoing interfaces.
How is the final metric that
Add the bandwidth and delay metric calculations
EIGRP uses calculated?
together
What is the algorithm EIGRP
DUAL (Diffusing Update Algorithm)
uses to determine the best
path?
What are the four main features Loop-free paths
that DUAL provides?
What are the terms associated
with DUAL?
9.4.2
Define successor.
Define feasible distance(FD).
9.4.3
Define feasible successor(FS).
Define feasibility condition
(FC).
9.4.4
9.4.4.2
9.4.6
9.4.6.2
9.4.6.3
9.5.1
Loop-free backup paths which can be used
immediately
Fast convergence
Minimum bandwidth usage with bounded updates
Successor
Feasible Distance (FD)
Feasible Successor (FS)
Reported Distance (RD) or Advertised Distance (AD)
Feasible Condition or Feasibility Condition (FC)
a neighboring router that is used for packet forwarding
and is the least-cost route to the destination network
the lowest calculated metric to reach the destination
network
a neighbor who has a loop-free backup path to the
same network as the successor by satisfying the
feasibility condition
when a neighbor's reported distance (RD) to a network
is less than the local router's feasible distance to the
same destination network
an EIGRP neighbor's feasible distance to the same
destination network.
EIGRP topology table or topology database
Define Reported Distance (RD)
or Advertised Distance (AD)
Where are the successor,
feasible distance, and any
feasible successors with their
reported distances kept by a
router?
What command will show you
show ip eigrp topology
the topology database?
Know each piece of the
topology table.
What is the centerpiece of
Finite State Machine (FSM)
EIGRP is DUAL and its EIGRP
route-calculation engine called?
What does the FSM define?
a set of possible states that something can go through,
what events cause those states, and what events result
from those states
What happens after the
DUAL searches for and then install a new route in the
interface is shut down?
routing table
What state does DUAL place a Active
route in if the successor goes
down and there is no feasible
successor?
What happens if the sender
It will not have a route to the network.
does not receive replies that
have a route to the network?
What happens if a packet
It is dropped
matches the parent route but
not any of the child routes?
What happens is you disable
The null0 routes are removed
9.5.1.2
9.5.3
9.5.4
9.5.5
9.5.5.2
auto summarization?
What happens to all
adjacencies after the no autosummary command is issued?
What command is used to
enter a manual route
summarization?
What happens to the routing
table after the above command
is entered?
What type of route can be used
with any of the routing
protocols we have used so far?
What command is used to
include a static default route
with its EIGRP routing
updates?
What does a default route
provide a default path to?
What can be changed to
improve EIGRP?
What are the two areas
discussed that can also be fine
tuned?
What happens if the hold time
is not adjusted when the hello
interval is adjusted?
What should the hold time be
set to?
All adjacencies are removed and recalculated
Router(config-if)#ip summary-address eigrp asnumber network-address subnet-mask
A summary route is listed instead of the individual
subnets
The "quad zero" static default route
redistribute static
outside the routing domain
Bandwidth utilization
Hello intervals and hold times
The neighbor adjacency will go down before the next
hello interval expires
3 times the hello interval