Trip over the same rock fantastic....
Spanning Tree Protocol is where you want to go. Here's a typical symptom: Install new workstation on high end switch to troubleshoot multimedia through firewall. Connection fails. Link light fine. Realize all other cu ports are static address servers. Further realize DHCP uses broadcast for address. Static address on workstation connects. Hummmm. STP is the culprit. Why it comes up as a default for simple non-redundant route switched systems I'll leave up to the conjecturests. (Yes, I do know the advertised reason.) If you look at a STP packet through a sniffer, most of the settings will become clear. The most important is the time it takes to become what's known as in a 'forwarding' state. Typically this adds up to 50 seconds. Blocking--listening --learning and finally forwarding. By the time most of a minute has passed, Microsoft devices needing an address have given up. They have no address and so, have no network connection. I've tripped over this rock in my early days of Cisco switching. I'm tempted to entirely disable STP, in my environment; point to point, non-redundant, no ring. There have been discussions on this in previous threads. I believe the answer was similar to my feelings --- why not, if you don't need it? Not sure of the C(isco)ompany line, though. Port fast, simply enough, enables a quick STP forwarding state. Uplink fast is similar, but over trunked connections, I believe. Other vendors have other cutesy names for similar functions. And, by the way, while STP is a basic, and comparatively simple, those, like me, who have not much switching stick time, have found it confounding in that 'real world' we frequent. That world sometimes has some serious time limitations. I tend to learn more quickly by knowing what I looking for. Very best, G. VP OGC -----Original Message----- From: MADMAN [mailto:[EMAIL PROTECTED]] Sent: Wednesday, November 14, 2001 10:54 AM To: [EMAIL PROTECTED] Subject: Re: Uplink fast and Port fast [7:26236] Nothing wrong with questions but for these real basic things a simple search will work and you will learn more by looking around and reading: http://www.cisco.com/ Dave William wrote: > > Dear all, > > Any one know what is uplink fast and port fast? > > Thanks a lot!! -- David Madland Sr. Network Engineer CCIE# 2016 Qwest Communications Int. Inc. [EMAIL PROTECTED] 612-664-3367 "Emotion should reflect reason not guide it" Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=26297&t=26236 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
