" hubs, concentrators, switches, bridges, etc... to this interface when portfast is enabled, can cause temporary bridging loops."
Those are all Layer 2 devices. A router is a layer 3 device (unless you explicitly turn bridging on). Ken Matlock Network Analyst 303-467-4671 [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Chris Gotstein Sent: Wednesday, May 23, 2012 1:19 PM To: Gert Doering Cc: [email protected] Subject: Re: [c-nsp] Lot of input errors on a NPE-G1 interface %Warning: portfast should only be enabled on ports connected to a single host. Connecting hubs, concentrators, switches, bridges, etc... to this interface when portfast is enabled, can cause temporary bridging loops. My understanding of this was a router would be included as well since it's used to connect multiple hosts. I only enable portfast on ports connected to end-user devices. I don't see a good reason to enable it on ports connected to routers, but that's just how it was explained to me, I very well could be wrong. On 5/23/2012 1:29 PM, Gert Doering wrote: > Hi, > > On Wed, May 23, 2012 at 01:15:16PM -0500, Chris Gotstein wrote: >> It's probably not going to address the overrun issue, but from a best >> practices stand point, it should not be enabled on interfaces that >> connected to other connected devices, ie a router or switch. > > Uh, so it should only be turned on for switchports that connect to... > "no device"? > > Anyway: right for "to switch", dead wrong for "to router". It should > be turned on for any connection that is known to not go to a switch or > hub, and doubly so if rapid-pvstp is used (due to TCNs being sent on a > link flap otherwise, possibly causing stalls elsewhere). > > As far as a switch is concerned, a "router" is the same thing as "a > host" - it doesn't forward layer2 things, so can't cause a routing loop. > > gert > -- ---- ---- ---- ---- Chris Gotstein, Network Engineer, U.P. Logon/Computer Connection U.P. http://uplogon.com | +1 906 774 4847 | [email protected] _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/ *** Exempla Confidentiality Notice *** The information contained in this message may be privileged and confidential and protected from disclosure. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any other dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify me immediately by replying to the message and deleting it from your computer. Thank you. *** Exempla Confidentiality Notice *** _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
