I'm steadily improving the network from little/no redundancy to complete redundancy. I have to pick my budget battles right now and frankly there are a few other places I'd rather improve first. Fortunately all my server switches are linked via ether-channel. Although no matter how many links in your bundle, if you lose your STP root, then you are going to have a re-convergence. I had a core switch roll over on me due to a "parity error" (according to TAC) a few months ago. Things recovered really well, but I haven't implemented the voice yet so I didn't have anything quite that latency dependent at the time.
On Wed, Mar 9, 2011 at 8:38 PM, Jay Taylor <[email protected]> wrote: > Any chance of just doubling your links for each path? That would only > require 2 extra pairs of fiber to each IDF rather than uplinking each > switch. But then again, that 1 ping missed with RSTP was with default timers > and I'm sure you could trim that down. > > > On Wed, Mar 9, 2011 at 9:32 PM, Michael Smith <[email protected]> wrote: >> >> Well you guys are right. I've always dealt with switches that have been >> etherchannelled to another switch so I never really dealt with switches that >> are single linked like that. I just don't know the reason why anybody >> wouldn't etherchannel their switches together. Hey I guess you live and you >> learn! >> >> >> >> > Date: Wed, 9 Mar 2011 20:28:21 -0600 >> > Subject: Re: [OSL | CCIE_RS] Rapid Spanning Tree convergence times >> > From: [email protected] >> > To: [email protected] >> > CC: [email protected]; [email protected] >> > >> > Right because in my situation one of the links to the cores is going >> > to be in blocking state. I don't see any way around that. >> > >> > On Wed, Mar 9, 2011 at 8:25 PM, Jay Taylor <[email protected]> wrote: >> > > Even with HSRP and sub-second hellos you could lose pings depending on >> > > how >> > > STP needed to converge. >> > > >> > > On Wed, Mar 9, 2011 at 9:24 PM, Michael Smith <[email protected]> >> > > wrote: >> > >> >> > >> Well I'm talking as far as the VOIP phones go. They obviously need a >> > >> gateway and to not miss any pings you can always turn on HSRP. >> > >> I'm not saying HSRP has anything to do with spanning tree. Just >> > >> thinking >> > >> about the fact of not losing any pings. >> > >> >> > >> >> > >> >> > >> ________________________________ >> > >> Date: Wed, 9 Mar 2011 21:05:04 -0500 >> > >> Subject: Re: [OSL | CCIE_RS] Rapid Spanning Tree convergence times >> > >> From: [email protected] >> > >> To: [email protected] >> > >> CC: [email protected]; [email protected] >> > >> >> > >> Maybe I'm missing something but how can HSRP (or first hop redundancy >> > >> protocol) replace STP/Etherchannel? Even if 2 of the Catalyst >> > >> switches in >> > >> that topology were L3 gateways and ran HSRP you still need to deal >> > >> with the >> > >> L2 loop that exists. >> > >> >> > >> >> > >> On Wed, Mar 9, 2011 at 8:50 PM, [email protected] >> > >> <[email protected]> >> > >> wrote: >> > >> >> > >> Well if yor timers are that bad for VOIP you can always use hsrp if >> > >> you >> > >> don't want to use the etherchannel option. You can tune hsrp down to >> > >> milliseconds if you wanted to. Of course your distribution switches >> > >> need to >> > >> support an enhanced IOS image >> > >> >> > >> Sent from my Verizon Wireless Phone >> > >> >> > >> ----- Reply message ----- >> > >> From: "Jay Taylor" <[email protected]> >> > >> Date: Wed, Mar 9, 2011 7:57 pm >> > >> Subject: [OSL | CCIE_RS] Rapid Spanning Tree convergence times >> > >> To: "marc abel" <[email protected]> >> > >> Cc: <[email protected]> >> > >> >> > >> >> > >> Enable portfast on the host ports and you'll see a much quicker >> > >> transition. >> > >> Just labbed this up and with portfast enabled I lost a single ping >> > >> during >> > >> the failover. Without it enabled I lost 12. >> > >> >> > >> For the VoIP question - in production I'd recommend building with >> > >> Etherchannels just so STP never needs to converge. >> > >> >> > >> >> > >> On Wed, Mar 9, 2011 at 5:41 PM, marc abel <[email protected]> wrote: >> > >> >> > >> > I have 4 switches connected in a loop. >> > >> > >> > >> > Cat1-------------Cat2 >> > >> > | | >> > >> > | | >> > >> > Cat3----------Cat4 >> > >> > >> > >> > >> > >> > Cat 1 is the root, Cat 2 is the secondary root. All the switches >> > >> > are >> > >> > set to RPVSTP and I have confirmed that show spanning-tree shows >> > >> > RSTP >> > >> > as the protocol. Cat 4 shows it's interface to cat3 as it's root >> > >> > port >> > >> > and the interface to Cat3 as the Alternate. I have not tuned any >> > >> > timers. >> > >> > >> > >> > What should be the convergence time in this situation? >> > >> > >> > >> > If I run a ping from a host attached to Cat4 to a host attached to >> > >> > Cat1 and then I shut the Cat1-Cat3 interface (on the Cat1 side) it >> > >> > takes about 32 seconds before pings pick back up. I thought RSTP >> > >> > was >> > >> > supposed to converge in about 6 seconds? >> > >> > >> > >> > Another question, what is the fastest recovery time we can tune >> > >> > down >> > >> > to from RSTP? How do others tune this for VOIP? I know that I can >> > >> > get >> > >> > sub second convergence from OSPF but not all my switches have an >> > >> > appropriate image to run ospf. >> > >> > >> > >> > >> > >> > Thanks in advance. >> > >> > >> > >> > Marc >> > >> > _______________________________________________ >> > >> > For more information regarding industry leading CCIE Lab training, >> > >> > please >> > >> > visit www.ipexpert.com >> > >> > >> > >> _______________________________________________ >> > >> For more information regarding industry leading CCIE Lab training, >> > >> please >> > >> visit www.ipexpert.com >> > >> >> > >> >> > >> >> > >> >> > > >> > > > > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
