Let me clarify something else as well here. IF switch 1 and switch 2 are the only switches in the STP topology here then we can assume 1 of them is the root bridge. Lets assume SW1 is the root bridge. Because it is the root bridge, one of the interfaces on SW2 connecting to SW1 is the root port and the other is in blocking state. If that trunk went down, it would be considered a DIRECT link failure, and SW2 would not need to wait max-age ...it detects a direct link failure and just waits 2x forward-delay (listening and learning).
With that being said...you could do a few other things too. You could implement uplinkfast here so that it would start forwarding IMMEDIATELY after direct failure. You could also implement RSTP. So the answer to your question is "it depends" but in a simple network with 2 switches the answer is #1 On Wed, Jul 22, 2009 at 9:17 PM, Joe Astorino <[email protected]>wrote: > Option #1 assuming the question means it will wait 16 seconds AFTER max_age > has already expired. After max_age expires it is 2x forward-delay. > > Option #2 assuming the question means it will wait 16 seconds in total. > > I suppose it depends on how you interpret "...when a port fails". My best > guess is option #1, but in the real lab if I got this,I would ask the > proctor and give him the information you just gave me so he knows that you > know what you are talking about. > > Also: > > Max-Age is still 20 seconds even with RSTP/MST (verify this by doing show > span in either of those modes). There is a subtle difference. RSTP/MST can > detect a failure in 6 seconds (3x hello-time of 2 seconds) but that is a > different function than the max age. The hello BPDUs in RSTP/MST work > differently than in traditional STP and PVSTP+ because in RSTP/MST the > hellos are used between routers on each segment as sort of a "keepalive." > > On Wed, Jul 22, 2009 at 9:08 PM, M Jay <[email protected]> wrote: > >> Hi >> I need help in this question: >> >> SW1 connected with SW2 through trunk ports, when a port fails the other >> port will wait for 16 second before the interface begins forwarding. >> >> Possible soltuions: >> >> SW1 >> spanning-tree VLANx forward-time 8 >> >> Or >> >> Spannin-tree VLANx forward-time 5 >> spanning-tree VLANx max-age 6 >> >> As forward-time includes listening and learning phases (5+5= 10) do I need >> to include the max-age time of 6 seconds ? Does max-age time effects in >> forwarding state of interface ?? >> >> Please assist!!!! >> >> Thanks >> >> >> >> >> >> ------------------------------ >> Windows Live™ SkyDrive™: Store, access, and share your photos. See >> how.<http://windowslive.com/Online/SkyDrive?ocid=TXT_TAGLM_WL_CS_SD_photos_072009> >> >> _______________________________________________ >> For more information regarding industry leading CCIE Lab training, please >> visit www.ipexpert.com >> >> > > > -- > Regards, > > Joe Astorino - CCIE #24347 R&S > Technical Instructor - IPexpert, Inc. > Cell: +1.586.212.6107 > Fax: +1.810.454.0130 > Mailto: [email protected] > -- Regards, Joe Astorino - CCIE #24347 R&S Technical Instructor - IPexpert, Inc. Cell: +1.586.212.6107 Fax: +1.810.454.0130 Mailto: [email protected]
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