Your network consists of a large hub-and-spoke Frame Relay network with a CIR of 56 kb/s
for each spoke. Which statement about the selectionof a dynamic protocol is true? Select
the best response.
A.
EIGRP would be appropriate if LMI type ANSI is NOT used.
B.
EIGRP would be appropriate, because the Frame Relayspokes could be segmented into
their own areas.
C.
EIGRP would be appropriate, because by default, queries are not propagated across the
slow speed Frame Relay links.
D.
EIGRP would be appropriate, because you can manage how much bandwidth is
consumed over the Frame Relay interface.
Explanation:
By default, EIGRP will limit itself to using no more than 50% of the interface bandwidth. The
primary benefit of controlling EIGRP’s bandwidth usage is to avoid losing EIGRP packets,
which could occur when EIGRP generates data faster than the interface line can absorb it.
This is of particular benefit on Frame Relay networks, where the access interface bandwidth
and the PVC capacity may be very different.
For example, in our Frame Relay topology a Hub is connected with 4 Spoke routers. The
main Frame Relay interface on Hub router is 512Kpbswhich is not enough to use for 6 links
of 128 Kbps ( = 768 Kbps).
The solution here is we can use 512 / 6 = 85 Kbps on each subinterface of Hub by using
“bandwidth 85″command. For example:
Hub(config)#interface Serial0/0.1 point-to-point
Hub(config-subif)#bandwidth 85
Also on Spoke routers we need to set this value. For example on Spoke1:
Spoke1(config)#interface Serial0/1.0 point-to-point
Spoke1(config-subif)#bandwidth 85
Notice that by default, EIGRP limits itself to use no more than 50% of the configured
interface bandwidth. In this case EIGRP will not use more than 42.5 Kbps (50% of 85 Kbps).
(For more information about implementing EIGRP overFrame Relay, please read http://
www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094063.shtml)
