Variance question

Posted on 2011-10-22
Medium Priority
Last Modified: 2013-01-04
Can someone please expain why the answer is 3 on this one? variance q
Question by:ee4itpro
  • 2
LVL 50

Accepted Solution

Don Johnston earned 2000 total points
ID: 37013974
First, router A will only have 3 routes to the data center.


BCH would not have been advertised to A because it has a cost of 30 while BEH is only 20. The same is true for FGH since FEH has a lower cost.

To determine the number of unequal cost paths, first find the BEST path. In this case DEH at 30.

Then multiply that by the variance which is 2. 30*2=60.

Any paths of 60 or better will be used.

DEH is already in the routing table at a cost of 30
BEH is 60
FEH is 40
LVL 17

Expert Comment

ID: 37014745
Paths must also meet the feasibility condition for them to be considered by variance i.e. their advertised distance must be less than the current FD. They must be successor's or feasible successors.

Expert Comment

ID: 37016256
A-D-E-H main route
A-B-C-H =70 ( this route comply to the FD condition), but ( A-D-E-H) x variance=60 > A-B-C-H=70, so this route will not be added to the routing table.
Correct answer should be A ( 1 route ).

Expert Comment

ID: 37016267
sorry :D , instead of ( A-D-E-H) x variance=60 > A-B-C-H=70, ( A-D-E-H) x variance=60 < A-B-C-H=70

Featured Post

Become a Leader in Data Analytics

Gain the power to turn raw data into better business decisions and outcomes in your industry. Transform your career future by earning your MS in Data Analytics. WGU’s MSDA program curriculum features IT certifications from Oracle and SAS.  

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Many of the companies I’ve worked with have embraced cloud solutions due to their desire to “get out of the datacenter business.” The ability to achieve better security and availability, and the speed with which they are able to deploy, is far grea…
Let’s face it: one of the reasons your organization chose a SaaS solution (whether Microsoft Dynamics 365, Netsuite or SAP) is that it is subscription-based. The upkeep is done. Or so you think.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
Both in life and business – not all partnerships are created equal. Spend 30 short minutes with us to learn:   • Key questions to ask when considering a partnership to accelerate your business into the cloud • Pitfalls and mistakes other partners…
Suggested Courses

616 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question