Just one minor correction on Tyson's response. Port ID used by STP is derived from SNMP ifindex for that port.
-- Marko Milivojevic - CCIE #18427 Senior Technical Instructor - IPexpert YES! We include 400 hours of REAL rack time with our Blended Learning Solution! Mailto: [email protected] Telephone: +1.810.326.1444 Fax: +1.810.454.0130 Web: http://www.ipexpert.com/ On Wed, Jun 23, 2010 at 14:39, Tyson Scott <[email protected]> wrote: > 1 Yes > > 2 Yes > > 3 Total Accumulated Path Cost to the root Bridge > > 4. The number of times SPT has been recalculated on the Path > > 5. A port set to mode dynamic desirable will default to access mode if no > device negotiates on the remote end yet it is still the recommendation to > set the mode to access when you know it is connected to end devices. > > > > HTH > > > > Regards, > > > > Tyson Scott - CCIE #13513 R&S, Security, and SP > > Managing Partner / Sr. Instructor - IPexpert, Inc. > > Mailto: [email protected] > > Telephone: +1.810.326.1444, ext. 208 > > Live Assistance, Please visit: www.ipexpert.com/chat > > eFax: +1.810.454.0130 > > > > IPexpert is a premier provider of Self-Study Workbooks, Video on Demand, > Audio Tools, Online Hardware Rental and Classroom Training for the Cisco > CCIE (R&S, Voice, Security & Service Provider) certification(s) with > training locations throughout the United States, Europe, South Asia and > Australia. Be sure to visit our online communities at > www.ipexpert.com/communities and our public website at www.ipexpert.com > > > > From: [email protected] > [mailto:[email protected]] On Behalf Of Atle Ørn Hardarson > Sent: Wednesday, June 23, 2010 5:21 AM > To: [email protected] > Subject: [OSL | CCIE_RS] show spanning-tree int xx detail > > > > Hi everyone > > > > Can someone please explain to me so that I understand the following output > better: > > > > switch# show spanning-tree interface Po1 detail > > > > Port 1665 (Port-channel1) of VLAN0001 is designated forwarding > > Port path cost 3, Port priority 128, Port Identifier 128.1665. > > Designated root has priority 24577, address 0009.12e9.aec0 > > Designated bridge has priority 32769, address 0014.f113.fc00 > > Designated port id is 128.1665, designated path cost 10 > > Timers: message age 0, forward delay 0, hold 0 > > Number of transitions to forwarding state: 16 > > Link type is point-to-point by default > > BPDU: sent 9090982, received 2782 > > > > > > Please find the breakdown of my questions below: > > > > "Port 1665 (Port-channel1) of VLAN0001 is designated forwarding" > > *** Where does the switch get the value of "Port 1665" from? Is this an STP > internal identifier of the port? > > > > "Port path cost 3, Port priority 128, Port Identifier 128.1665." > > *** The port path cost and port priority shown here are LOCAL values, am I > correct in this assumption? There are no cumulative values represented here. > > > > "Designated port id is 128.1665, designated path cost 10" > > *** The designated port ID is the REMOTE value sent from the neighboring > switch, but *what* is the "designated path cost" and how is it calculated? > > *** Is the designated path cost the same as the "root path cost"? > > > > "Number of transitions to forwarding state: 16" > > *** What exactly does this mean? I used to think that this number > represented the classic STP states, but a value of 16 has me confused. What > states are they referring to here? > > > > "Link type is point-to-point by default" > > *** In Cisco's CCIE official study guide, it is recommended that a port > channel is configured with the "spanning-tree link-type point-to-point" > command, in order to facilitate a quick connection, but is it really > necessary to hard-code this command on the interface, as it is obviously the > default link-type on etherchannel? A bit confusing > > > > Thanks! > > > > Atle > > _______________________________________________ > 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
