D is obviously a right answer and has nothing to do with switching
performance or how fast a router forwards traffic. The answer said
"bandwidth utilization," not throughput. The issue is how much bandwidth a
routing protocol uses to send route updates, hellos, etc. Mostly it's an
issue for distance-vector routing protocols. On a large network with
low-speed serial links, you probably don't want to use a distance-vector
protocol. This is an issue that is covered in the CID class.
In the Cisco Press CID book, see page 135 for a general discussion of how
much bandwidth is consumed by routing updates. On page 184 of the Cisco
Press CID book, see an IGRP example with 1000 routes and 50 DLCIs. The
result is 63.7 Kbps bandwidth utilization, which could be a large chunk.
See page 223 for a discussion of IPX RIP and SAP bandwidth utilization. See
page 238 for a discussion of bandwidth utilization by AppleTalk RTMP.
As another example, consider a large enterprise network with 500 routes.
Say, you're using RIPv1 on a Frame Relay network with a hub-and-spoke
design. To save money, you have a CIR of only 256 Kbps at the hub router.
The hub router has 50 DLCIs defined. RIPv1 sends an update every 30 seconds
for each subinterface (DLCI). RIP only allows 25 routes per packet, so 20
packets are required for each update. A full-size RIP packet, not counting
a data-link-layer header is 532 bytes. How much bandwidth will you consume
just sending routing-protocol updates? Does it leave any bandwidth for
sending user data?
Is this a design issue? Is this real-world (are there still networks that
look like this?) Is bandwidth utilization a consideration when selecting a
routing protocol? Does Cisco want you to know this? YES TO ALL OF THOSE.
I haven't seen the Boson test. Did it allow all 4 answers to be right? I
gather that it must not have allowed this or there would be no discussion.
All the answers are correct, although "address flexibility" is poorly
written. I guess they mean addressing flexibility and are referring to
support for VLSM, discontiguous subnets, and supernetting.
Priscilla
At 11:14 PM 8/7/01, Baety Wayne A1C 18 CS/SCBX wrote:
>If you look at this question one way, one
>Answer sticks out like a swore thumb.
>
>When deciding on a particular routing protocol
>(one vs. another) What protocol considerations for
>routing are most likely to be made?
>
>A) resource utilization
> (Does the impact to a router's resource utililization for a particular
> protocol significant. i.e. OSPF is resource intensive during SPF
> calculations)
>
>b) address flexibility
> (Is address flexibility significant in protocol selection.
> i.e. RIPv1 allows no flexibility in address assignment beyond
> initially choosing a default subnet mask used throughout
> The contingent domain)
>
>c) convergence time
> (Does the impact on how fast a protocol views the entire network
> consistently at all points of routing decision significant in
> protocol selection. EIGRP has extremely fast convergence
> characteristics in the face of redundant links and )
>
>d) bandwidth utilization
> (Does the impact on how well one routing protocol vs another manages
> available bandwidth for forwarding traffic significant in routing
> protocol selection? i.e. Does one routing protocol forward traffic
> faster than another?)
>
>
>in that case choice d is more a switching method design choice, I'd bet
>there are other questions on this test dealing with switching methods,
>therefore this question acts as a primer for those.
>
>Of course, if I was taking this test I would have wanted to click all the
>answers, but since I know test makers always put a "All above" at the end
>for the questions they want answered in that fashion, I would have been this
>critical in deciding the answers. In test taking, repeat the question, (or
>questionize the statement) for each answer and usually you'll see the light
>8)
>
>IMHO
>
>Wayne
>
>
>-----Original Message-----
>From: Stephen Skinner [mailto:[EMAIL PROTECTED]]
>Sent: Wednesday, August 08, 2001 2:41 AM
>To: [EMAIL PROTECTED]
>Subject: CID test question [7:15131]
>
>howdy...
>
>do you chaps agree or disagree....i personally think it should be ABD
>
>indetify the considerations for routing protocol selection
>A) resource utilization
>b) address Flexibilty
>c) convergence time
>d) bandwidth utilization
>
>it says A,B,C ....i say A,C,D.....your thought please
>
>steve
>
>_________________________________________________________________
>Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp
________________________
Priscilla Oppenheimer
http://www.priscilla.com
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=15339&t=15131
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