EIGRP Summarization with Default Routing:
=====================================
ip prefix-list CONNECTED_TO_EIGRP seq 5 permit 4.0.0.0/24
ip prefix-list CONNECTED_TO_EIGRP seq 10 permit 4.0.1.0/24
ip prefix-list CONNECTED_TO_EIGRP seq 15 permit 4.0.2.0/24
ip prefix-list CONNECTED_TO_EIGRP seq 20 permit 4.0.3.0/24
!
route-map CONNECTED_TO_EIGRP permit 10
match ip address prefix-list CONNECTED_TO_EIGRP
!
router eigrp 100
redistribute connected route-map CONNECTED_TO_EIGRP
!
interface Tunnel0
ip summary-address eigrp 100 0.0.0.0 0.0.0.0
Summarization can also be used to originate a default route in EIGRP. The
disadvantage of this configuration, however, is that all subnets previously advertised
out an interface will be suppressed, because all IPv4 networks are a subnet of the
EIGRP Summarization with Leak Map
=================================
ip prefix-list CONNECTED_TO_EIGRP seq 5 permit 4.0.0.0/24
ip prefix-list CONNECTED_TO_EIGRP seq 10 permit 4.0.1.0/24
!
route-map CONNECTED_TO_EIGRP permit 10
match ip address prefix-list CONNECTED_TO_EIGRP
!
ip prefix-list LOOPBACK40 seq 5 permit 4.0.0.0/24
!
route-map LEAK_LOOPBACK40 permit 10
match ip address prefix-list LOOPBACK40
!
router eigrp 100
redistribute connected route-map CONNECTED_TO_EIGRP
!
interface Tunnel0
ip summary-address eigrp 100 0.0.0.0 0.0.0.0 leak-map LEAK_LOOPBACK40
EIGRP Floating Summarization:
============================
When summaries are created in EIGRP, OSPF, and BGP, the router automatically
installs a route to Null0 to match the summary. This is used to prevent the router
from forwarding traffic for destinations inside the summary that it does not have a
longer match for. However, in certain designs this can be an undesirable behavior.
To resolve this, EIGRP sets its interface-level summaries to have an administrative
distance of 5 by default. This means that any other route with a distance of 1–4 will
take precedence over the summary.
EIGRP Poisoned Floating Summarization:
======================================
On R5:
router eigrp 100
network 155.1.45.0 0.0.0.255
network 155.1.58.0 0.0.0.255
network 160.1.5.0 0.0.0.255
summary-metric 160.1.4.0/23 distance 255
!
interface GigabitEthernet1.58 -- To R8
ip summary-address eigrp 100 160.1.4.0 255.255.254.0
Before Applying:
---------------
R8#show ip route eigrp | b Gateway
Gateway of last resort is 155.1.58.5 to network 0.0.0.0
D* 0.0.0.0/0 [90/3328] via 155.1.58.5, 00:19:31, GigabitEthernet1.58
155.1.0.0/16 is variably subnetted, 7 subnets, 2 masks
D 155.1.45.0/24 [90/3072] via 155.1.58.5, 00:19:31, GigabitEthernet1.58
160.1.0.0/24 is subnetted, 1 subnets
D 160.1.5.0 [90/130816] via 155.1.58.5, 00:00:32, GigabitEthernet1.58
With only summary route:
------------------------
!R8#show ip route eigrp | b Gateway
Gateway of last resort is 155.1.58.5 to network 0.0.0.0
D* 0.0.0.0/0 [90/3328] via 155.1.58.5, 00:23:16, GigabitEthernet1.58
155.1.0.0/16 is variably subnetted, 7 subnets, 2 masks
D 160.1.4.0 [90/130816] via 155.1.58.5, 00:00:22, GigabitEthernet1.58
!R5#show ip route eigrp | b Gateway
Gateway of last resort is 155.1.45.4 to network 0.0.0.0
D* 0.0.0.0/0 [90/3072] via 155.1.45.4, 00:23:37, GigabitEthernet1.45
160.1.0.0/16 is variably subnetted, 3 subnets, 3 masks
D 160.1.4.0/23 is a summary, 00:00:42, Null0
After poisoning:
---------------
!R5#show ip route eigrp | b Gateway
Gateway of last resort is 155.1.45.4 to network 0.0.0.0
D* 0.0.0.0/0 [90/3072] via 155.1.45.4, 00:27:26, GigabitEthernet1.45
!R8#show ip route eigrp | b Gateway
Gateway of last resort is 155.1.58.5 to network 0.0.0.0
D* 0.0.0.0/0 [90/3328] via 155.1.58.5, 00:27:39, GigabitEthernet1.58
EIGRP Metric Weights
====================
By default, EIGRP uses only bandwidth and delay to calculate its composite metric,
as K1=K3=1 and K2=K4=K5=K6=0. Load, reliability, and extended attributes can
also be used, or the ratio at which bandwidth and delay are used can be changed,
by modifying the metric weights . Specifically, the calculation is as follows for
Classic EIGRP, which uses a 32-bit metric:
For 32 bit:
Metric = 256*[(K1*Scaled Bw) + (K2*Scaled Bw)/(256 - Load) + (K3*Scaled Delay)]*[K5/(Reliability + K4)]
For 64 bit:
Metric = [(K1*Minimum Throughput + (K2*Minimum Throughput/(256-Load) + (K3*Total Latency) + (K6*Extended Attributes)
If K5 equals zero, the second half of the equation is ignored in both cases. "Scaled
Bw" equals 107/(Minimum Bw/Kbps) and "Scaled Delay" equals (Delay/10) in
microseconds. "Minimum Throughput" equals (107 * 65535)/(Minimum Bw/Kbps),
"Total Latency" equals (Delay * 65536)/10 in microseconds for links below 1
GigabitEthernet and (107 * 65536/10)/Bw in microseconds for links above 1
GigabitEthernet.
R8#show ip protocols | section eigrp
Routing Protocol is "eigrp 100"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Default networks flagged in outgoing updates
Default networks accepted from incoming updates
EIGRP-IPv4 Protocol for AS(100) Metric weight K1=0, K2=0, K3=1, K4=0, K5=0
EIGRP Unequal Cost Load Balancing:
=================================
router eigrp 100
variance 5
EIGRP Convergence Timers:
=========================
interface GigabitEthernet1.146
ip hello-interval eigrp 100 1
ip hold-time eigrp 100 3
Unlike OSPF, EIGRP hello and hold-time intervals do not need to match to form
adjacencies. Just like OSPF, the locally configured Hello interval defines the local
rate interval for sending EIGRP hello packets, but the value is not transmitted in
EIGRP Hello packets. Unlike OSPF, the locally configured Hold-Time interval
defines for how long the remote router will wait for a EIGRP packet before resetting
the adjacency, so the value is transmitted in EIGRP Hello packets
EIGRP Stub Routing:
===================
router eigrp 100
eigrp stub connected
The EIGRP stub feature is used to limit the scope of EIGRP query messages and to
further limit which routes a neighbor advertises
EIGRP Stub Routing with Leak Map:
=============================
ip prefix-list R8_LOOPBACK0 seq 5 permit 150.1.8.8/32
!
route-map STUB_LEAK_MAP deny 10
match ip address prefix-list R8_LOOPBACK0
!
route-map STUB_LEAK_MAP permit 20
!
router eigrp 100
eigrp stub connected leak-map STUB_LEAK_MAP
EIGRP Filtering with Passive Interface:
====================================
router eigrp 100
passive-interface default
no passive-interface GigabitEthernet1.67
The passive-interface command in EIGRP, like in RIPv2, stops the sending of
updates out an interface. Unlike RIPv2, however, passive-interface in EIGRP will
prevent forming of an adjacency on the interface because it stops sending EIGRP
Hello packets as well, and hence the learning of any updates on the link.
EIGRP Filtering with Prefix-Lists:
=================================
Configure prefix-list filtering on R1 so that it does not install any updates received
from R4 on the VLAN 146 segment.
Allow all routes to be received from all other EIGRP neighbors
ip prefix-list NOT_FROM_R4 seq 5 deny 155.1.146.4/32
ip prefix-list NOT_FROM_R4 seq 10 permit 0.0.0.0/0 le 32
!
ip prefix-list PERMIT_ALL seq 5 permit 0.0.0.0/0 le 32
!
router eigrp 100
distribute-list prefix PERMIT_ALL gateway NOT_FROM_R4 in
EIGRP Filtering with Standard Access-Lists:
=========================================
Configure a one-line standard access-list on R9 to filter out all routes coming from R7
that have an odd number in the third octet.
access-list 1 permit 0.0.0.0 255.255.254.255
!
router eigrp 100
distribute-list 1 in GigabitEthernet1.79
EIGRP Filtering with Extended Access-Lists:
==========================================
Like RIP, extended access-lists when called as a distribute-list in IGP have a
different meaning than in redistribution or in BGP. With BGP and redistribution, the
“source” field in the ACL represents the network address, and the “destination” field
represents the subnet mask. In IGP distribute-list application, the “source” field in
the ACL matches the update source of the route, and the “destination” field
represents the network address. This implementation allows us to control which
networks we are receiving, but more importantly who we are receiving them from.
With VLAN 45 interface disabled and before the filter is applied, R5 routes as
follows
EIGRP Filtering with Offset Lists:
=================================
Configure an offset-list on R7 so traffic destined for R3’s Loopback0 prefix is sent to
R6.
If the Ethernet link to R6 is down, traffic should be rerouted directly to R3.
R7:
access-list 1 permit host 150.1.3.3
!
router eigrp 100
offset-list 1 in 2000 GigabitEthernet1.37
Like in RIP, the offset-list feature in EIGRP is used to modify the metric on a perroute
basis or a per-interface basis. Before any metric modifications, we can see
that R7 is routing directly to R3 to reach 150.1.3.3/32. There are no additional
entries in the EIGRP topology table of R7 for this prefix because R6 also routes
through R7 to reach it:
R7#show ip route 150.1.3.3
Routing entry for 150.1.3.3/32
Known via "eigrp 100", distance 90, metric 130816, type internal
Redistributing via eigrp 100
Last update from 155.1.37.3 on GigabitEthernet1.37, 01:05:42 ago
Routing Descriptor Blocks: * 155.1.37.3, from 155.1.37.3, 01:05:42 ago, via GigabitEthernet1.37
!R7#show ip eigrp topology 150.1.3.3/32
EIGRP-IPv4 Topology Entry for AS(100)/ID(150.1.7.7) for 150.1.3.3/32
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 130816
Descriptor Blocks: 155.1.37.3 (GigabitEtherGigabitEthernet1.37), from 155.1.37.3, Send flag is 0x0
Composite metric is (130816/128256)
****************
R7#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.R7(config)#router eigrp 100
R7(config-router)#offset-list 1 in 2000 GigabitEthernet1.37****************
!R7#show ip route 150.1.3.3
Routing entry for 150.1.3.3/32
Known via "eigrp 100", distance 90, metric 131328, type internal
Redistributing via eigrp 100
Last update from 155.1.67.6 on GigabitEthernet1.67, 00:00:15 ago
Routing Descriptor Blocks: * 155.1.67.6, from 155.1.67.6, 00:00:15 ago, via GigabitEthernet1.67
!R7#show ip eigrp topology 150.1.3.3/32
EIGRP-IPv4 Topology Entry for AS(100)/ID(150.1.7.7) for 150.1.3.3/32
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 131328
Descriptor Blocks: 155.1.67.6 (GigabitEthernet1.67), from 155.1.67.6, Send flag is 0x0
Composite metric is (131328/131072)
155.1.37.3 (GigabitEthernet1.37), from 155.1.37.3, Send flag is 0x0
Composite metric is (132816/130256), route is Internal*************************
EIGRP Filtering with Administrative Distance:
============================================
Configure administrative distance filtering on R6 so that it does not install the route to
R4’s Loopback0 prefix.
R6:
access-list 4 permit host 150.1.4.4
!
router eigrp 100
distance 255 0.0.0.0 255.255.255.255 4
EIGRP Filtering with Per Neighbor AD:
======================================
Configure administrative distance filtering on R3 so that traffic destined for R7’s
Loopback0 prefix is sent to R1.
ensure R3 never uses the direct path via R7.
R3:
access-list 7 permit host 150.1.7.7
!
router eigrp 100
distance 255 155.1.37.7 0.0.0.0 7
The administrative distance for EIGRP internal routes can be changed on a
per-prefix basis, but external EIGRP routes cannot
EIGRP Filtering with Route Maps:
=================================
route-map FILTER_ON_TAGS deny 10
match tag 4
!
route-map FILTER_ON_TAGS permit 20
!
router eigrp 100
distribute-list route-map FILTER_ON_TAGS in
Unlike BGP, filtering with route-maps in IGP is usually limited to redistribution
filtering only. However, EIGRP supports route-map filtering as a distribute-list with
matches on metric and tag values. Route tags are set at the time of redistribution
and can be used like BGP community values to group prefixes together without
having to match on the actual route in a prefix-list or access-list.
EIGRP Bandwidth Pacing:
======================
Configure R5 so that EIGRP cannot use more than 200Kbps of bandwidth on its
DMVPN connection, assuming that the link speed is 2Mbps.
interface Tunnel0
bandwidth 2000
ip bandwidth-percent eigrp 100 10
By default EIGRP can use up to maximum 50% of the administrative bandwidth of
the interface. The absolut value can be changed by modifying the bandwidth on the
interface or by changing the percentage level with interface-level command
ip bandwidth-percent eigrp <AS_NR> <percentage> . Verify the SRTT and Pacing timers
for the tunnel interface before bandwidth usage is changed:
EIGRP Default Metric:
=====================
ip route 160.1.2.2 255.255.255.255 155.1.23.2
!
router eigrp 100
redistribute static
default-metric 100000 10 255 1 1500
When redistributing static and connected prefixes into EIGRP or between EIGRP
processes, metrics are automatically derived from the source prefix. For all other
redistribution, the metric must be manually set on the redistribute statement, under a
route-map, or from the default metric. The default metric affects all redistributed
prefixes for which a specific metric has not been configured.
EIGRP Neighbor Logging:
=====================
router eigrp 100
no eigrp log-neighbor-changes
eigrp log-neighbor-warnings 20
EIGRP Router-ID:
==============
EIGRP uses the router-id field in external routes as a loop prevention mechanism.
The router that originates the external route inserts its EIGRP router-id into the
update. If an update is received back in with a router-id in this field matching the
local router-id, the update is dropped.
EIGRP Maximum Hops:
==================
Configure all devices in EIGRP AS 100 so that routes with a hop count of greater
than 5 are considered invalid
R1 – R10:
router eigrp 100
metric maximum-hops 5
=====================================
ip prefix-list CONNECTED_TO_EIGRP seq 5 permit 4.0.0.0/24
ip prefix-list CONNECTED_TO_EIGRP seq 10 permit 4.0.1.0/24
ip prefix-list CONNECTED_TO_EIGRP seq 15 permit 4.0.2.0/24
ip prefix-list CONNECTED_TO_EIGRP seq 20 permit 4.0.3.0/24
!
route-map CONNECTED_TO_EIGRP permit 10
match ip address prefix-list CONNECTED_TO_EIGRP
!
router eigrp 100
redistribute connected route-map CONNECTED_TO_EIGRP
!
interface Tunnel0
ip summary-address eigrp 100 0.0.0.0 0.0.0.0
Summarization can also be used to originate a default route in EIGRP. The
disadvantage of this configuration, however, is that all subnets previously advertised
out an interface will be suppressed, because all IPv4 networks are a subnet of the
EIGRP Summarization with Leak Map
=================================
ip prefix-list CONNECTED_TO_EIGRP seq 5 permit 4.0.0.0/24
ip prefix-list CONNECTED_TO_EIGRP seq 10 permit 4.0.1.0/24
!
route-map CONNECTED_TO_EIGRP permit 10
match ip address prefix-list CONNECTED_TO_EIGRP
!
ip prefix-list LOOPBACK40 seq 5 permit 4.0.0.0/24
!
route-map LEAK_LOOPBACK40 permit 10
match ip address prefix-list LOOPBACK40
!
router eigrp 100
redistribute connected route-map CONNECTED_TO_EIGRP
!
interface Tunnel0
ip summary-address eigrp 100 0.0.0.0 0.0.0.0 leak-map LEAK_LOOPBACK40
EIGRP Floating Summarization:
============================
When summaries are created in EIGRP, OSPF, and BGP, the router automatically
installs a route to Null0 to match the summary. This is used to prevent the router
from forwarding traffic for destinations inside the summary that it does not have a
longer match for. However, in certain designs this can be an undesirable behavior.
To resolve this, EIGRP sets its interface-level summaries to have an administrative
distance of 5 by default. This means that any other route with a distance of 1–4 will
take precedence over the summary.
EIGRP Poisoned Floating Summarization:
======================================
On R5:
router eigrp 100
network 155.1.45.0 0.0.0.255
network 155.1.58.0 0.0.0.255
network 160.1.5.0 0.0.0.255
summary-metric 160.1.4.0/23 distance 255
!
interface GigabitEthernet1.58 -- To R8
ip summary-address eigrp 100 160.1.4.0 255.255.254.0
Before Applying:
---------------
R8#show ip route eigrp | b Gateway
Gateway of last resort is 155.1.58.5 to network 0.0.0.0
D* 0.0.0.0/0 [90/3328] via 155.1.58.5, 00:19:31, GigabitEthernet1.58
155.1.0.0/16 is variably subnetted, 7 subnets, 2 masks
D 155.1.45.0/24 [90/3072] via 155.1.58.5, 00:19:31, GigabitEthernet1.58
160.1.0.0/24 is subnetted, 1 subnets
D 160.1.5.0 [90/130816] via 155.1.58.5, 00:00:32, GigabitEthernet1.58
With only summary route:
------------------------
!R8#show ip route eigrp | b Gateway
Gateway of last resort is 155.1.58.5 to network 0.0.0.0
D* 0.0.0.0/0 [90/3328] via 155.1.58.5, 00:23:16, GigabitEthernet1.58
155.1.0.0/16 is variably subnetted, 7 subnets, 2 masks
D 160.1.4.0 [90/130816] via 155.1.58.5, 00:00:22, GigabitEthernet1.58
!R5#show ip route eigrp | b Gateway
Gateway of last resort is 155.1.45.4 to network 0.0.0.0
D* 0.0.0.0/0 [90/3072] via 155.1.45.4, 00:23:37, GigabitEthernet1.45
160.1.0.0/16 is variably subnetted, 3 subnets, 3 masks
D 160.1.4.0/23 is a summary, 00:00:42, Null0
After poisoning:
---------------
!R5#show ip route eigrp | b Gateway
Gateway of last resort is 155.1.45.4 to network 0.0.0.0
D* 0.0.0.0/0 [90/3072] via 155.1.45.4, 00:27:26, GigabitEthernet1.45
!R8#show ip route eigrp | b Gateway
Gateway of last resort is 155.1.58.5 to network 0.0.0.0
D* 0.0.0.0/0 [90/3328] via 155.1.58.5, 00:27:39, GigabitEthernet1.58
EIGRP Metric Weights
====================
By default, EIGRP uses only bandwidth and delay to calculate its composite metric,
as K1=K3=1 and K2=K4=K5=K6=0. Load, reliability, and extended attributes can
also be used, or the ratio at which bandwidth and delay are used can be changed,
by modifying the metric weights . Specifically, the calculation is as follows for
Classic EIGRP, which uses a 32-bit metric:
For 32 bit:
Metric = 256*[(K1*Scaled Bw) + (K2*Scaled Bw)/(256 - Load) + (K3*Scaled Delay)]*[K5/(Reliability + K4)]
For 64 bit:
Metric = [(K1*Minimum Throughput + (K2*Minimum Throughput/(256-Load) + (K3*Total Latency) + (K6*Extended Attributes)
If K5 equals zero, the second half of the equation is ignored in both cases. "Scaled
Bw" equals 107/(Minimum Bw/Kbps) and "Scaled Delay" equals (Delay/10) in
microseconds. "Minimum Throughput" equals (107 * 65535)/(Minimum Bw/Kbps),
"Total Latency" equals (Delay * 65536)/10 in microseconds for links below 1
GigabitEthernet and (107 * 65536/10)/Bw in microseconds for links above 1
GigabitEthernet.
R8#show ip protocols | section eigrp
Routing Protocol is "eigrp 100"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Default networks flagged in outgoing updates
Default networks accepted from incoming updates
EIGRP-IPv4 Protocol for AS(100) Metric weight K1=0, K2=0, K3=1, K4=0, K5=0
EIGRP Unequal Cost Load Balancing:
=================================
router eigrp 100
variance 5
EIGRP Convergence Timers:
=========================
interface GigabitEthernet1.146
ip hello-interval eigrp 100 1
ip hold-time eigrp 100 3
Unlike OSPF, EIGRP hello and hold-time intervals do not need to match to form
adjacencies. Just like OSPF, the locally configured Hello interval defines the local
rate interval for sending EIGRP hello packets, but the value is not transmitted in
EIGRP Hello packets. Unlike OSPF, the locally configured Hold-Time interval
defines for how long the remote router will wait for a EIGRP packet before resetting
the adjacency, so the value is transmitted in EIGRP Hello packets
EIGRP Stub Routing:
===================
router eigrp 100
eigrp stub connected
The EIGRP stub feature is used to limit the scope of EIGRP query messages and to
further limit which routes a neighbor advertises
EIGRP Stub Routing with Leak Map:
=============================
ip prefix-list R8_LOOPBACK0 seq 5 permit 150.1.8.8/32
!
route-map STUB_LEAK_MAP deny 10
match ip address prefix-list R8_LOOPBACK0
!
route-map STUB_LEAK_MAP permit 20
!
router eigrp 100
eigrp stub connected leak-map STUB_LEAK_MAP
EIGRP Filtering with Passive Interface:
====================================
router eigrp 100
passive-interface default
no passive-interface GigabitEthernet1.67
The passive-interface command in EIGRP, like in RIPv2, stops the sending of
updates out an interface. Unlike RIPv2, however, passive-interface in EIGRP will
prevent forming of an adjacency on the interface because it stops sending EIGRP
Hello packets as well, and hence the learning of any updates on the link.
EIGRP Filtering with Prefix-Lists:
=================================
Configure prefix-list filtering on R1 so that it does not install any updates received
from R4 on the VLAN 146 segment.
Allow all routes to be received from all other EIGRP neighbors
ip prefix-list NOT_FROM_R4 seq 5 deny 155.1.146.4/32
ip prefix-list NOT_FROM_R4 seq 10 permit 0.0.0.0/0 le 32
!
ip prefix-list PERMIT_ALL seq 5 permit 0.0.0.0/0 le 32
!
router eigrp 100
distribute-list prefix PERMIT_ALL gateway NOT_FROM_R4 in
EIGRP Filtering with Standard Access-Lists:
=========================================
Configure a one-line standard access-list on R9 to filter out all routes coming from R7
that have an odd number in the third octet.
access-list 1 permit 0.0.0.0 255.255.254.255
!
router eigrp 100
distribute-list 1 in GigabitEthernet1.79
EIGRP Filtering with Extended Access-Lists:
==========================================
Like RIP, extended access-lists when called as a distribute-list in IGP have a
different meaning than in redistribution or in BGP. With BGP and redistribution, the
“source” field in the ACL represents the network address, and the “destination” field
represents the subnet mask. In IGP distribute-list application, the “source” field in
the ACL matches the update source of the route, and the “destination” field
represents the network address. This implementation allows us to control which
networks we are receiving, but more importantly who we are receiving them from.
With VLAN 45 interface disabled and before the filter is applied, R5 routes as
follows
EIGRP Filtering with Offset Lists:
=================================
Configure an offset-list on R7 so traffic destined for R3’s Loopback0 prefix is sent to
R6.
If the Ethernet link to R6 is down, traffic should be rerouted directly to R3.
R7:
access-list 1 permit host 150.1.3.3
!
router eigrp 100
offset-list 1 in 2000 GigabitEthernet1.37
Like in RIP, the offset-list feature in EIGRP is used to modify the metric on a perroute
basis or a per-interface basis. Before any metric modifications, we can see
that R7 is routing directly to R3 to reach 150.1.3.3/32. There are no additional
entries in the EIGRP topology table of R7 for this prefix because R6 also routes
through R7 to reach it:
R7#show ip route 150.1.3.3
Routing entry for 150.1.3.3/32
Known via "eigrp 100", distance 90, metric 130816, type internal
Redistributing via eigrp 100
Last update from 155.1.37.3 on GigabitEthernet1.37, 01:05:42 ago
Routing Descriptor Blocks: * 155.1.37.3, from 155.1.37.3, 01:05:42 ago, via GigabitEthernet1.37
!R7#show ip eigrp topology 150.1.3.3/32
EIGRP-IPv4 Topology Entry for AS(100)/ID(150.1.7.7) for 150.1.3.3/32
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 130816
Descriptor Blocks: 155.1.37.3 (GigabitEtherGigabitEthernet1.37), from 155.1.37.3, Send flag is 0x0
Composite metric is (130816/128256)
****************
R7#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.R7(config)#router eigrp 100
R7(config-router)#offset-list 1 in 2000 GigabitEthernet1.37****************
!R7#show ip route 150.1.3.3
Routing entry for 150.1.3.3/32
Known via "eigrp 100", distance 90, metric 131328, type internal
Redistributing via eigrp 100
Last update from 155.1.67.6 on GigabitEthernet1.67, 00:00:15 ago
Routing Descriptor Blocks: * 155.1.67.6, from 155.1.67.6, 00:00:15 ago, via GigabitEthernet1.67
!R7#show ip eigrp topology 150.1.3.3/32
EIGRP-IPv4 Topology Entry for AS(100)/ID(150.1.7.7) for 150.1.3.3/32
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 131328
Descriptor Blocks: 155.1.67.6 (GigabitEthernet1.67), from 155.1.67.6, Send flag is 0x0
Composite metric is (131328/131072)
155.1.37.3 (GigabitEthernet1.37), from 155.1.37.3, Send flag is 0x0
Composite metric is (132816/130256), route is Internal*************************
EIGRP Filtering with Administrative Distance:
============================================
Configure administrative distance filtering on R6 so that it does not install the route to
R4’s Loopback0 prefix.
R6:
access-list 4 permit host 150.1.4.4
!
router eigrp 100
distance 255 0.0.0.0 255.255.255.255 4
EIGRP Filtering with Per Neighbor AD:
======================================
Configure administrative distance filtering on R3 so that traffic destined for R7’s
Loopback0 prefix is sent to R1.
ensure R3 never uses the direct path via R7.
R3:
access-list 7 permit host 150.1.7.7
!
router eigrp 100
distance 255 155.1.37.7 0.0.0.0 7
The administrative distance for EIGRP internal routes can be changed on a
per-prefix basis, but external EIGRP routes cannot
EIGRP Filtering with Route Maps:
=================================
route-map FILTER_ON_TAGS deny 10
match tag 4
!
route-map FILTER_ON_TAGS permit 20
!
router eigrp 100
distribute-list route-map FILTER_ON_TAGS in
Unlike BGP, filtering with route-maps in IGP is usually limited to redistribution
filtering only. However, EIGRP supports route-map filtering as a distribute-list with
matches on metric and tag values. Route tags are set at the time of redistribution
and can be used like BGP community values to group prefixes together without
having to match on the actual route in a prefix-list or access-list.
EIGRP Bandwidth Pacing:
======================
Configure R5 so that EIGRP cannot use more than 200Kbps of bandwidth on its
DMVPN connection, assuming that the link speed is 2Mbps.
interface Tunnel0
bandwidth 2000
ip bandwidth-percent eigrp 100 10
By default EIGRP can use up to maximum 50% of the administrative bandwidth of
the interface. The absolut value can be changed by modifying the bandwidth on the
interface or by changing the percentage level with interface-level command
ip bandwidth-percent eigrp <AS_NR> <percentage> . Verify the SRTT and Pacing timers
for the tunnel interface before bandwidth usage is changed:
EIGRP Default Metric:
=====================
ip route 160.1.2.2 255.255.255.255 155.1.23.2
!
router eigrp 100
redistribute static
default-metric 100000 10 255 1 1500
When redistributing static and connected prefixes into EIGRP or between EIGRP
processes, metrics are automatically derived from the source prefix. For all other
redistribution, the metric must be manually set on the redistribute statement, under a
route-map, or from the default metric. The default metric affects all redistributed
prefixes for which a specific metric has not been configured.
EIGRP Neighbor Logging:
=====================
router eigrp 100
no eigrp log-neighbor-changes
eigrp log-neighbor-warnings 20
EIGRP Router-ID:
==============
EIGRP uses the router-id field in external routes as a loop prevention mechanism.
The router that originates the external route inserts its EIGRP router-id into the
update. If an update is received back in with a router-id in this field matching the
local router-id, the update is dropped.
EIGRP Maximum Hops:
==================
Configure all devices in EIGRP AS 100 so that routes with a hop count of greater
than 5 are considered invalid
R1 – R10:
router eigrp 100
metric maximum-hops 5
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