Information Technology Reference
In-Depth Information
Record the formula used to calculate the
default
EIGRP composite metric.
Default metric = [K1*bandwidth + K3*delay] * 256
What command do you use to verify the K values used by EIGRP?
show ip protocols
What command do you use to verify the actual values of the EIGRP metric?
show interface
The
bandwidth
metric is displayed in Kbit (kilobits). Most serial interfaces use the default value of
1,544,000
bps, which is the value for a
T1
connection. The value might or might not reflect the actual
physical
bandwidth
of the interface. If the actual
bandwidth
of the link differs from the default value,
you should modify the value.
Delay
is a measure of the time it takes for a packet to traverse a route. This metric is a static value and
is expressed in
microseconds
.
Reliability
is a measure of the probability that the link will fail or how often the link has experienced
errors. Unlike delay, it is measured dynamically with a value between
0
and
255
, with
1
being a mini-
mally reliable link and
255
being 100 percent reliable. Reliability is calculated on a 5-minute
weight-
ed
average to avoid the sudden impact of high (or low) error rates.
Load
reflects the amount of traffic utilizing the link. It is measured dynamically with a value between
0
and
255
. A
lower
value is more desirable because it indicates a less saturated link.
Modifying the Bandwidth
On most serial links, the bandwidth metric will default to 1544 Kbits. This is the case with all the
serial interfaces in Packet Tracer Exercise 9-1. However, notice in the chapter topology shown earlier
in Figure 9-6 that the links between HQ and the Branch routers each have an actual bandwidth that is
not the same as the default value on the interfaces.
Record the commands necessary on each router to change the bandwidth metric to match the actual
bandwidth. Remember: HQ will have to modify the bandwidth on all interfaces connected to Branch
routers.
HQ commands to change bandwidth:
HQ(config)#
int s0/0/1
HQ(config-if)#
bandwidth 768
HQ(config-if)#
int s0/1/0
HQ(config-if)#
bandwidth 512
HQ(config-if)#
int s0/1/1
HQ(config-if)#
bandwidth 384
B1 commands to change bandwidth:
B1(config)#
int s0/0/0
B1(config-if)#
bandwidth 768
B2 commands to change bandwidth:
B2(config)#
int s0/0/0
B2(config-if)#
bandwidth 512