640-811 drag and drop 1

[hauchinango]

Has anyone taken the 640-811 and had the Drag and Drop question regarding routing protocols? It ask to match characteristics to the protocols. Here is what I have:

RIP
-uses hop count to determine best path
-has max hop count of 15
-has default admin distance of 120

IGRP
-has max hop count of 255????????
-Has default admin distance of 100

EIGRP
-uses DUAL algorithm
-supports classles routing
-Max hop count of 224?????????????

Items Remaining
-uses SPF algorithm
-Has defualt admin distance of 110

I am unsure of the hop counts on the IGRP and EIGRP, but confident on the others.

Thanks

 

[Greenice]

Looks right to me. The only one that's a bit of a mystery is the max hop count for EIGRP. Lammle's book says 255, while a practice exam question from Odom's book says 224. Found only a couple of references on Google - one of which was an EIGRP powerpoint slide from the Cisco Networking Academy - it also said 224. You can check it here,

http://hills.ccsf.edu/~lbaca/CCNA3v3_Mod03.ppt.

Note that the default max hop count for IGRP and EIGRP is 100.

Cheers.

 

[hauchinango]

The max hop count is the one I was unsure of. Found conflicting results for EIGRP.

thanks

 

[Lundah]

Wow, where was this info 2 months ago. Thanks for the info on this, another one that apparently got me yesterday. I believe on this one I put the 255 hop count under EIGRP, and put SPF algorithm under IGRP.

 

[CiscoGuy33]

Did a Google on EIGRP and hop count, appears per Cisco it is 220.

From Cisco -

http://www.cisco.com/warp/public/103/eigrp-toc.html

Very long white paper but talks about metrics at the very bottom
--------------------------------------------------------

Enhanced Interior Gateway Routing Protocol
Document ID: 16406

Introduction
Enhanced Interior Gateway Routing Protocol (EIGRP) is an interior gateway protocol suited for many different topologies and media. In a well designed network, EIGRP scales well and provides extremely quick convergence times with minimal network traffic.............

-------- Lots of content left out here ----------

........Vector metric shows the individual metrics used by EIGRP to calculate the cost to a network. EIGRP does not propagate total cost information throughout the network; the vector metrics are propagated, and each router computes the cost and reported distance individually.

------- more content deleted here --------------

Hop count is 2 This is not used in metric calculations, but does limit the maximum size of an EIGRP AS. The maximum number of hops that EIGRP will accept is 100 by default, although the maximum can be configured to 220 with metric maximum hops.

---------------------------------------------------------

I hope this helps !!!





E.A. Broda
CCNA, CCDA, CCAI, Network +

 

[Cluebird]

The maximum number of hops is 255 just like IGRP. Under the routing process on the router the command "metric maximum hops" has an upper limit of 255. I would not be surprised if there are typos in the documentation or the 220 number is for an older implementation of EIGRP.

 

[CiscoGuy33]

Cluebird,

Thanks I thought it was 255, I guess Cisco docs can be wrong also......

I even checked the whitepaper for a "last update" - it had been updated 1-10-2005?

To settle it once and for all I went to the source, what I should have checked right away but I was off and did not have access to the lab -

a Cisco 2610 router running IOS 12.1(4)

--------- EIGRP ---------------------------------

Lab-B(config)#router eigrp 100
Lab-B(config-router)#network 219.17.100.0
Lab-B(config-router)#?
Router configuration commands:
metric Modify IGRP routing metrics and parameters
Lab-B(config-router)#metric ?
holddown Enable IGRP holddown
maximum-hops Advertise IGRP routes greater than <hops> as unreachable
weights Modify IGRP metric coefficients

Lab-B(config-router)#metric max
Lab-B(config-router)#metric maximum-hops ?
<1-255> Hop count

--------- IGRP ----------------------------------

Lab-B(config)#router igrp 100
Lab-B(config-router)#network 199.6.13.0
Lab-B(config-router)#metric ?
holddown Enable IGRP holddown
maximum-hops Advertise IGRP routes greater than <hops> as unreachable
weights Modify IGRP metric coefficients

Lab-B(config-router)#metric max
Lab-B(config-router)#metric maximum-hops ?
<1-255> Hop count

I hope this settles it for all once and for all - per a Cisco 2610 router the max hops for EIGRP and IGRP is 255.

Keep networking along .......



E.A. Broda
CCNA, CCDA, CCAI, Network +