Hi
Lab was on gns3 attempted a few different IOS's and platforms including the VXR 7200's all the same behaviour
I'd like to try it on real hardware time-permitting but hoping someone bails me out
-- BR Tony Sent from my iPhone on 3 > On 7 Oct 2013, at 14:29, "Venkataramanaiah.R" <vramanaiah_at_gmail.com> wrote: > > Dear Tony, > > I would suggest you to run a different version of IOS and try out... I > can only suspect a bug here. > > The behavior you are experience is indeed strange.. It is surprising > to see the route installed in RIB while it is not shown in topology > table. > > Regards > >> On 10/7/13, Joe Astorino <joeastorino1982_at_gmail.com> wrote: >> Hmmmm....also this Cisco white paper seems to agree with the book and with >> how I thought it worked. They have a simplified version of what you are >> testing with easier to read numbers. >> >> In the example, the path through D is not chosen because it's metric is not >> < variance * FD. However, it also goes on to make this point: >> >> "Also, the reported distance of neighbor D is 25, which is greater than the >> feasible distance (FD) of 20 through C. This means that, even if variance >> is set to 3, the E-D-A path is not selected for load balancing because >> Router D is not a feasible successor." >> >> This seems to certainly be making the case that to be considered for >> unequal cost load balancing via variance, a path must first pass the >> feasibility condition. Clearly, your lab results show otherwise though. >> >> http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a008009437d.shtml#var >> >> >> >> >> On Mon, Oct 7, 2013 at 3:34 AM, Joe Astorino >> <joeastorino1982_at_gmail.com>wrote: >> >>> This certainly seems strange to me. Granted, it is like 4AM or something >>> here, but if you had asked me I would have thought EIGRP would not >>> consider >>> the F1/0 path for anything, given it doesn't meet the feasibility >>> condition. I'd certainly be interested to hear if anybody else has an >>> answer. >>> >>> >>> >>> >>>> On Sun, Oct 6, 2013 at 2:53 PM, Tony Singh <mothafungla_at_gmail.com> wrote: >>>> >>>> CCNP ROUTE 642-902 Official Certification Guide >>>> >>>> "Routes that are neither successor nor feasible successor can never be >>>> added to the IP routing table, regardless of the variance setting" >>>> >>>> I did a little lab >>>> >>>> --- r2 --- >>>> r1 ----r3 ---- r5 loopback 5.5.5.5 >>>> ----r4 ---- >>>> >>>> >>>> no variance >>>> >>>> all-links >>>> P 5.5.5.5/32, 1 successors, FD is 158720, serno 55 >>>> via 10.0.0.1 (158720/156160), FastEthernet0/0 >>>> via 20.0.0.1 (161536/158976), FastEthernet1/1 >>>> via 30.0.0.1 (1790976/156160), FastEthernet1/0 >>>> >>>> topology >>>> P 5.5.5.5/32, 1 successors, FD is 158720 >>>> via 10.0.0.1 (158720/156160), FastEthernet0/0 >>>> via 30.0.0.1 (1790976/156160), FastEthernet1/0 >>>> >>>> global-rib >>>> D 5.5.5.5 [90/158720] via 10.0.0.1, 00:00:44, FastEthernet0/0 >>>> >>>> >>>> the reason we choose f1/0 path as FS over f1/1 is due to the AD<FD of >>>> successor holding true even if it has a worse FD - expected behaviour >>>> and >>>> end result no load-balancing as no equal cost paths (max 4 equal cost >>>> paths >>>> by default) >>>> >>>> >>>> >>>> >>>> if I apply a variance of x2 >>>> >>>> >>>> >>>> all-links >>>> P 5.5.5.5/32, 2 successors, FD is 158720, serno 52 >>>> via 10.0.0.1 (158720/156160), FastEthernet0/0 >>>> via 20.0.0.1 (161536/158976), FastEthernet1/1 >>>> via 30.0.0.1 (1790976/156160), FastEthernet1/0 >>>> >>>> topology >>>> P 5.5.5.5/32, 2 successors, FD is 158720 >>>> via 10.0.0.1 (158720/156160), FastEthernet0/0 >>>> via 30.0.0.1 (1790976/156160), FastEthernet1/0 >>>> >>>> global-rib >>>> D 5.5.5.5 [90/158720] via 10.0.0.1, 00:00:53, FastEthernet0/0 >>>> [90/161536] via 20.0.0.1, 00:00:53, FastEthernet1/1 >>>> >>>> >>>> ok so we're now permitting the f1/1 path being installed as a viable >>>> load-balancing destination, this shows me two things, first that dual >>>> will >>>> permit a non-successor or non-feasible successor into global rib as >>>> viable >>>> load-balancing paths and second dual compares the end-to-end FD for >>>> making >>>> a decision on which path it would prefer to load-balance looking at the >>>> all-links topology as f1/1 has a lower FD than f1/0 >>>> >>>> >>>> >>>> this does make the above argument invalid - im wondering if EIGRP has >>>> since >>>> been enhanced for this DUAL behaviour? if so then I guess the whole >>>> point >>>> for the statement in the first place was to avoid a loop i.e if you're >>>> not >>>> a successor or feasible successor then you a loop, what has changed? >>>> >>>> >>>> -- >>>> BR >>>> >>>> Tony >>>> >>>> >>>> Blogs and organic groups at http://www.ccie.net >>>> >>>> _______________________________________________________________________ >>>> Subscription information may be found at: >>>> http://www.groupstudy.com/list/CCIELab.html >>> >>> >>> -- >>> Regards, >>> >>> Joe Astorino >>> CCIE #24347 >>> http://astorinonetworks.com >>> >>> "He not busy being born is busy dying" - Dylan >> >> >> >> -- >> Regards, >> >> Joe Astorino >> CCIE #24347 >> http://astorinonetworks.com >> >> "He not busy being born is busy dying" - Dylan >> >> >> Blogs and organic groups at http://www.ccie.net >> >> _______________________________________________________________________ >> Subscription information may be found at: >> http://www.groupstudy.com/list/CCIELab.html Blogs and organic groups at http://www.ccie.netReceived on Mon Oct 07 2013 - 15:33:24 ART
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