Hi Dale, The bandwidth that is set on R7 s0/0/0 is completely irrelevant to the calculation. It could be set to 1544k it could be set for 10Gb it will make no difference to R8 in it's calculations. The reason is because R7 makes it's own calculation based on it's knowledge of the minimum bandwidth and cumulative delay and then sends that information to R8. R8 will then crunch it's own numbers.
So basically R7 says "the minimum bandwidth to my directly connected loopback interface is 10,000,000 Kbps". R7 sends that information along with it's delay of 5000 uSec to R8 and also crunches the numbers based on the formula 256*min_bw + delay. R8 gets the information and says "R7 has a minimum bandwidth of 10,000,000 Kbps. What do I have? Oh, I have 1544k on my s0/0/0 interface (inbound interface)....mine is better. min_bw = 1544k." It also adds in the delay of s0/0/0 to the delay R7 sent R8. If you set this up in a lab check out a "sh ip eigrp topology 7.7.7.7/32" on R8. Then change the bandwidth on s0/0/0 and run it again. Nothing will change. On Wed, Mar 3, 2010 at 4:32 PM, Dale Shaw <[email protected]<dale.shaw%[email protected]> > wrote: > Hi Marko, > > On Thu, Mar 4, 2010 at 8:28 AM, Marko Milivojevic <[email protected]> > wrote: > > On Wed, Mar 3, 2010 at 21:01, Dale Shaw > > <[email protected]<dale.shaw%[email protected]>> > wrote: > >> > >> Is the bandwidth value on R7's s0/0/0 interface really used to > >> determine the minimum bandwidth along the path from R8 to R7's > >> loopback? > > > > The lowest bandwidth on the path is always used... The chain is only as > > strong as its weakest link :-) > > But the scenario was calculating the metric from R8 to R7's loopback. > Is the bandwidth value on R7's serial interface _facing R8_ used? :-) > > cheers, > Dale > -- Regards, Joe Astorino CCIE #24347 (R&S) Sr. Technical Instructor - IPexpert Mailto: [email protected] Telephone: +1.810.326.1444 Live Assistance, Please visit: www.ipexpert.com/chat eFax: +1.810.454.0130 IPexpert is a premier provider of Classroom and Self-Study Cisco CCNA (R&S, Voice & Security), CCNP, CCVP, CCSP and CCIE (R&S, Voice, Security & Service Provider) Certification Training with locations throughout the United States, Europe and Australia. Be sure to check out our online communities at www.ipexpert.com/communities and our public website at www.ipexpert.com
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