links, define the bandwidth of the link for the
purpose of sending routing update traffic, using the
bandwidth kilobits command. In this command, the
parameter kilobits indicates the intended bandwidth in
kilobits per second. For example, for a 64-kbps link, use the
following command: router(config-if)#bandwidth 64 If you
do not change the bandwidth for serial interfaces, EIGRP
assumes that the bandwidth on the link is the default T1 speed.
If the link is actually slower, the router might not be able to
converge, or routing updates might be lost. For generic serial
interfaces such as PPP or High-Level Data Link Control (HDLC),
set the bandwidth to the line speed. For Frame Relay on
point-to-point interfaces, set the bandwidth to the committed
information rate (CIR). For Frame Relay multipoint connections,
set the bandwidth to the sum of all CIRs, or if the permanent
virtual circuits (PVCs) have different CIRs, set the bandwidth
to the lowest CIR multiplied by the number of PVCs on the
multipoint connection.
Web Links Configuring
EIGRP
http://www.cisco.com/en/US/products/sw/iosswrel/
ps1828/products_configuration_guide_chapter0918
6a00800ca56e.html
Content 2.3
Implementing and Verifying EIGRP 2.3.2
Configuring Basic EIGRP Example Figure illustrates the
configuration of router A for EIGRP. Router A, along with all
routers in the figure, is part of EIGRP AS 109. For EIGRP to
establish a neighbor relationship, all neighbors must be in the
same autonomous system.Because the wildcard mask is not used in
the router A configuration, all interfaces on router A that are
part of networks 10.0.0.0/8 and 172.16.0.0/16 participate in
the EIGRP routing process. In this case, this includes all four
interfaces. Note that network 192.168.1.0 is not configured in
the EIGRP configuration on router A, because router A does not
have any interfaces in that network. In this example, consider
what would happen if the following configuration were entered
on router A: router eigrp 109
network
10.1.0.0
network 10.4.0.0
network
172.16.7.0
network 172.16.2.0 Router A would
change the network commands to have classful networks, and the
resulting configuration would be the following: router
eigrp 109
network 10.0.0.0
network 172.16.0.0 By
default, EIGRP summarizes networks on the classful boundary.
Alternatively, consider what would happen if the following
configuration were entered on router A: router eigrp
109
network 10.1.0.0 0.0.255.255
network 10.4.0.0 0.0.255.255
network 172.16.2.0
0.0.0.255
network 172.16.7.0 0.0.0.255 In this
case, router A uses the wildcard mask to determine which
directly connected interfaces participate in the EIGRP routing
process for AS 109. All interfaces that are part of networks
10.1.0.0/16, 10.4.0.0/16, 172.16.2.0/24, and 172.16.7.0/24
participate in the EIGRP routing process for AS 109; in other
words, all four interfaces participate in EIGRP. A wildcard
mask can be used to selectively configure which routes to
advertise. For example, a wildcard mask is useful when a router
in an autonomous system connects to a router external to its
autonomous system. In this case, the router can be configured
with a wildcard mask so that the router does not try to form an
adjacency with the router in the other autonomous system. For
instance, in Figure , router C includes subnets of the Class B
network 172.16.0.0 on all interfaces. The router C
configuration in the figure uses a wildcard mask, because
router C connects to a router external to AS 100 on its serial
interface, and EIGRP with AS 100 should not be run there.
Without the wildcard mask, router C would send EIGRP packets to
the external network, which would waste bandwidth and CPU
cycles and would provide unnecessary information to the
external network. The wildcard mask tells EIGRP to establish a
relationship with EIGRP routers from interfaces that are part
of subnets 172.16.3.0/24 or 172.16.4.0/24, but not
172.16.5.0/24.
Content 2.3 Implementing
and Verifying EIGRP 2.3.3 Configure Basic
Propagation of Default Route You can create an EIGRP
default route with the ip default-network
network-number global configuration command. The
configured router advertises the specified network listed as
the gateway of last resort. Other routers use their next-hop
address to the advertised network as their default route. The
network specified must be reachable by the router before it
announces the network as a candidate default route to other
EIGRP routers. The network must also be passed to other EIGRP
routers so that those routers can use this network as their
default network and gateway of last resort. Therefore, the
network must be either an EIGRP-derived network in the routing
table or generated using a static route that has been
redistributed into EIGRP. Multiple default networks can be
configured. Downstream routers use the EIGRP metric to
determine the best default route. For example, in Figure ,
router A is directly attached to external network
172.31.0.0/16. Router A is configured with the 172.31.0.0
network as a candidate default network using the ip
default-network 172.31.0.0 command. This network is passed
to router B, because router A has it listed in a network
command under the EIGRP process. Notice that the routing table
for router A does not set the gateway of last resort; the
ip default-network command does not benefit router A
directly. On router B, the EIGRP-learned 172.31.0.0 network is
flagged as a candidate default network (as indicated by the
asterisk [*] in the routing table). Router B also sets the
gateway of last resort to 10.64.0.2 (router A) to reach the
default network of 172.31.0.0. Note
When you
configure the ip default-network command, a static route
(the ip route command) is generated in the router
configuration. However, the Cisco IOS software does not display
a message to indicate this. The entry appears as a static route
in the routing table of the router in which the command is
configured, as can be seen in the router A configuration and
routing table in the figure. This entry can be confusing if you
want to remove the default network. The configuration must be
removed with the no ip default-network network
command. Static Default Routes
EIGRP and IGRP behave
differently than RIP when you are using the ip route 0.0.0.0
0.0.0.0 command. For example, EIGRP does not redistribute
the 0.0.0.0 0.0.0.0 default route by default. The configuration
in Figure results in the 0.0.0.0 route being passed to the
EIGRP neighbors of the router.
Content 2.3
Implementing and Verifying EIGRP 2.3.4
Verifying EIGRP Example Understanding which show
commands to use when troubleshooting the EIGRP configuration
saves valuable time. Use the show ip eigrp neighbors
command to verify that the router recognizes its neighbors. Use
the show ip route eigrp command to verify that the
router recognizes routes from its neighbors. Figure shows a
network that will be used to illustrate the configuration,
verification, and troubleshooting of EIGRP in this topic and
the following topics. The configuration of the R1 router is
also shown in the figure. EIGRP is enabled in AS 100. The