STP Loop after root bridge reload

10 3560 Switches with RSTP enabled and with default bridge priorities and with redundant links between.
One bridge is elected as RSTP root, redundant links are blocked. Setup is stable.
What happens if the root bridge is reloaded ?
Are there loops in the network after reload ?
br Fritz

Fritz
The short answer is no there should not be any loops if the root switch is reloaded because RSTP should elect a new root bridge and build a new loop free topology.
There will however obviously be an outage while the switches work out a new topology.
There will also be an outage when the reloaded switch comes back online because if it was root before because of it's lower bridge ID then it will become root again when it is fully up and running.
But you should not see any loops.
Note the word "should" because you can never be fully sure.
If you are proposing to do this on a live network you should always schedule an outage for this sort of thing because you never know what could happen.
Jon

Similar Messages

6513 stp root bridge and Dell powerconnect 5316 issue

Hi everyone,
have this issue with root bridge on on a vlan being learnt incorrectly by itself from another vlan.
The topology is this
6513        vlan 10       interface f4/10   Dell 5316 interface g11   vlan 1
                vlan 20       interface f4/20                   interface g16   vlan 20
The 6513 vlan 10 priority 12228                 Dell configured with classic stp and priority 32768
                vlan 20 priority 8192
pvst+ used on ios 12.1 (i know really old, but going to be de-commissioned any way).
Now on the cisco switch a show spanning-tree vl 20 it is entered and reports its the root for this vlan, ok correct there.
But when this is done for vlan 10 it reports that the root brodge is via f4/10 with the priority and mac address of vlan 20.
Somehow this shows that vlan 10 is getting bpdu's via the Dell 5316 from vlan 20 . The blade server connectivity is fine.
Thanks for any advice
Cheers
TJ.

Hi Reza,
Inherited issue. The ports are set to access. The servers are regular Windows servers (2008).
I agree would have been a better configured setup done that way with an etherchanel.
Also I noted that the interfaces on the Dell are set to untagged.
Cheers
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How to find out Secondary STP Root bridge in cisco switche network

Hi, i need to find out Root Primary and Root Secondary bridge in all my offices.
sh spanning-tree summary command can tell me which switch is root bridge primary, but how can i find secondary root easily with some simple command?
sh spanning-tree summary
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Root bridge for: VLAN0001-VLAN0002, VLAN0005, VLAN0008, VLAN0031

I'm not sure if there is a simple way of finding the bridge with the SECOND best priority.

Developing: Endless loop in Adobe Bridge with and Adobe Drive CMIS Connector

Hi
Currently I’m implementing a CMIS-Server for the dam system of my company, using the apache chemistry framework. One of the main requirements is that adobe drive works with it.
At the moment I implemented only the navigation services (getChildren, getObject, …) and the repository services and test them against adobe drive. It’s already possible to navigate through folders and read assets with ad4 and the finder. So 3 days ago I installed adobe bridge (CS6) and test my server again.
My test environment is very easy.
root(1 object)->test1(0 objects; empty)
First I’m opening my repository with adobe drive and then I switch to bridge and connect it. Bridge shows me the folder test1 with no errors. So I double-click it and now bridge is in an endless loop. The notification switch between ‘Keine anzuzeigenden Elemente’(No elements to show) and ‘Einen Moment bitte, die Suche läuft …’(Searching, please wait …). This only happens in bridge. When I open the folder with the finder it just works, without the loop.
So I logged all requests, which were send by adobe drive, and get this list.
Connecting with adobe drive
getRepositoryInfos
getTypeChildren (null) -> all basetypes
getTypeDecendants (cmis:document)
getTypeChildren (null) -> all basetypes (Why two times?)
getTypeDecendants (cmis:document) (Why two times?)
getRepositoryInfos (Why two times?)
getObjectByPath (/.hidden)
getObjectByPath (/.hidden)
getObjectByPath (/.hidden) (Why so often?)
getObjectByPath (/DCIM)
getObjectByPath (/mach_kernel)
getObjectByPath (/.Spotlight-V100)
getObjectByPath (/.metadata_never_index)
getObjectByPath (/.metadata_never_index_unless_rootfs)
getObjectByPath (/.metadata_never_index)
getObjectByPath (/mach_kernel)
getObjectByPath (/.metadata_never_index_unless_rootfs)
getChildren (cmis:folder,0) (rootfolder) returning only one element (test1)
getObjectParents(cmis:folder,127) (test1) returning the rootfolder
getObjectByPath (/.hidden)
getObjectByPath (/mach_kernel) …
Open the Cmis repository in bridge and doubleclick the repository
getChildren (cmis:folder,0) (rootfolder) returning only one element (test1)
getObjectParents(cmis:folder,127) (test1) returning the rootfolder
Then I double click the test1 folder
getObject(cmis:folder,127)(test1)
getChildren(cmis:folder,127) -> empty list
… (endless loop)
I already checked getObject and getChildren against a reference implementation (FileShare Repository of apache Chemistry) and it returns exactly the same structure. Only the name and the timestamps are different. So my second though was to check the repository capabilities and as well they are both equal. Now I’m a little bit desperate because I spend already 3 days in try and error bugfixing but nothing worked. So here are my questions.
Is there a logfile for bridge because I thing this refreshing happens after an exception. I already checked the adobe drive log and it contains only asset not found errors for (e.g mach_kernel …).
In which circumstances does bridge reloads a folder?
Debugging of adobe drive: I already read http://forums.adobe.com/message/3928595 but it doesn’t work in AD4 any more, I only get info/error/fatal messages.(I changed the log4j config files in AD4ServiceManager.) Does something changed or did I forget something?
Why does AD4 make 2 or more times the exact same request? (Look table above).
I hope my English is good enough to understand.
Thanks

After two months I'm a little bit smarter so I can answer some of my question by my own.
No there is no logfile for bridge, but I was able to debug the scriptcode from the ad plugin, which is installed in bridge.
If an error occures in the plugin
I was able to decompile the cmis connector. That helps a lot when ad logs with weird exceptions.
Because AD maps the actions of the filebrowser(finder,explorer) to cmis and this one does sometimes the exact action two or more times.
Unfortunately is wasn't able to fix my main problem, but I found a workaround to use cmis in bridge. I deactivated the ad plugin in bridge and after that action, bride display the cmis volume as normal volume. Sadly some actions like to manage relationships etc. are with this workaround not usable but for me this is alright.

Network Design - Root and Non root bridges

Hi,
We have a network set-up as the below image. Where the switches have STP enable to handle the muliple paths for the data to flow.
What I would like to know is should the 2 bridges plugged into the same switch e.g Switch A (Bridge A and Bridge B) both be root bridges and (Bridge C and Bridge D) both be non root.
Or should for example, Bridge A be a root and Bridge C a non root and Bridge B a non root and Bridge D the root?
Similarly with the rest of the other bridges E, F, G and H
Thanks

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Posting
Ah, I think I understand. So the wireless bridges are "transparent" to the rest of the network. They just convert wired to wireless and back again.
If I have that right, we can ignore them and just consider your switches.
In that case, it appears you have two L2 loops, those formed by the dual paths between switches A and B and between switches C and D. From a topology standpoint, it doesn't seem to matter what switch you select as root and secondary root. However, as switches B and C are the interior switches, I would suggest those as your root and secondary root switches.

Stp loop, Not able to trace source

Hello,
I am new to cisco switches and learning about cisco switches now. we have a LAN with 6509 as core router and 2950s/3550s as access switches.
When I ran wireshark on my machine, I saw an stp loop repeating from a cisco device. I have noted down the MAC-address and tried in vain to find the same in our LAN. I am seeing packets like Address: "Spanning-tree-(for-bridges)_00" and "loop reply". I am not able to see any of the MAC addresses found in this loop conversation, on my LAN. I read that these loops are not good for the network. Where can I start to resolve this problem?
Thanks in advance for your advice.

There is likely no problem at all. ;-)
If you were really experiencing a loop, you would have other problems.
Best for you will be to start making a study of spanning tree (STP) and it's inner workings. Here is a good starting point:
http://www.cisco.com/en/US/tech/tk389/tk621/tsd_technology_support_protocol_home.html
Armed with this knowledge you can try to analyze the traffic that was observed by wireshark.
regards,
Leo

Root Bridge can see NonRoot Bridges but does not Associate

This is a point-to-multipoint bridging LAN for networking eight serial devices (air quality monitors) to a central Windows box for real-time wireless data acquisition. Thus far, I have configured a single Aironet 1310 as the root bridge (RB: 150.100.0.2, 255.255.0.0) at the Windows box (PC: 150.100.0.1, 255.255.0.0) and three Aironet 1310s as non-root bridges (NRB1: 150.100.0.3; NRB2: 150.100.0.4; NRB3: 150.100.0.5). When the system's working, each of the NRBs will connect to an ethernet-to-serial device server with its own IP, and the serial devices will connect to the device servers as COM2-COM9, respectively. Each node in this network has an external antenna, an omni at the RB and directional/Yagi antennae at the NRBs. Distances are short, hundreds of meters, so power will not be the limiting factor. (We could have done this with Zigbee but decided to overdesign for reliability.)
After assigning IP addresses to all four bridges using the command-line interface, and with the RB connected to an ethernet hub/switch, we configured each of the NRBs by connecting them to the same hub/switch and using the browser interface. We used the document at
http://www.cisco.com/application/pdf/paws/68087/bridges_pt_to_pt.pdf
and followed it to the letter to configure first the RB, then the NRBs.
After configuring all four bridges, and while all four were still hard-wired together through the hub/switch, all four bridges showed the proper associations in the "State" column of the web interface under "Association." To test the wireless links we disconnected the three NRBs from the hub/switch by removing the ethernet cables, leaving the RB connected to the hub/switch (naturally) to maintain connection to the host PC. We then refreshed all associations.
On the RB web interface, all three NRBs showed up with the proper IP addresses, but the "State" fields showed "Attempting Association" or something like that rather than "EAP-Associated."
All three NRB web interfaces disappeared because the links were lost. I tried to PING each of the IP addresses using a DOS command, but all three timed out.
So, in short, the RB can "see" all three NRBs and "knows" they're there; but the association does not complete. What are my options for diagnosing the problem?
Thanks in advance...
Brent Auvermann
Amarillo, TX

Chieu Dinh,
For the non-root bridge, is there a way to set the scan? I can see in the log file shows that the scan is starting when I changed from Install to non-root bridge. Once I am on the non-root bridge role, I don't see any more the log for scanning.
I don't know about any command that controls the scanning interval when the bridge is in non-root mode. I also don't think it logs every time it goes into a scan cycle because I think they're pretty close together, maybe at most a few seconds.
My question is "is there some ways that I can initiate the scan on the non-root bridge?
You can shut/no-shut the non-root bridge radio interface. Every time you do this it intiates a new scan immediately.
can I use the "parent" command on the point-to-multipoint environment?
As far as I know, yes. I think the only mode parent doesn't work in is repeater mode. For repeaters, you don't configure a list of parents, you only configure one single MAC peer.
An added thought: if you are having trouble with the bridge link coming up, then there is likely either a signal or a configuration issue (and chasing the scan interval probably won't net you any solutions). I've found that a great way to narrow the troubleshooting is to configure the bridges on the ground at close range (maybe 50-100 feet apart, not right up against each other) to control for signal. Once you have a working configuration and you know for sure that the bridges will come up, then install them in your outdoor locations. Keep in mind that when outdoors, a lot of factors can play into signal claritiy and usability (trees/foliage, distance, LOS/fresnel, earth curvature, weather, noise and interference, etc.). Also, unfortunately for the 1310s, the 2.4GHz space is really congested in most populated areas so they are not a reliable solution unless you're out in the country. Always survey first.
Justin

Intallation loop after configuring X in Solaris 8

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It test my X setting, attempt to continue the installation, laungh a X test screen, goes back to the logging screen and says "All devices configured" go back to X test screen and then bag to the log screen and says the same "All devices configured" again. And it does it forever.
Does any one has an idea what is going on?
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Need to reboot root bridge for RF connectivity

We have installed RF connectivity with Cisco Aironet 1300 between two sites.The distance is 1 km.
The connectivity is intermittent and shows radio errors in logs.
After rebooting the root bridge at one site the connectivity is restored.
We have not been able to locate the problem . Plz Help
the configs are as below :
Site 1 :
ROOT BRIDGE
ip subnet-zero
aaa new-model
aaa group server radius rad_eap
aaa group server radius rad_mac
aaa group server radius rad_acct
aaa group server radius rad_admin
cache expiry 1
cache authorization profile admin_cache
cache authentication profile admin_cache
aaa group server tacacs+ tac_admin
cache expiry 1
cache authorization profile admin_cache
cache authentication profile admin_cache
aaa group server radius rad_pmip
aaa group server radius dummy
aaa authentication login eap_methods group rad_eap
aaa authentication login mac_methods local
aaa authorization exec default local
aaa accounting network acct_methods start-stop group rad_acct
aaa cache profile admin_cache
all
aaa session-id common
dot11 activity-timeout client default 99999
dot11 activity-timeout repeater default 99999
dot11 activity-timeout workgroup-bridge default 99999
dot11 activity-timeout bridge default 99999
dot11 ssid yyyy
authentication open
dot11 network-map
bridge irb
interface Dot11Radio0
bandwidth inherit
no ip address
no ip route-cache
ssid yyyy
speed basic-1.0 basic-2.0 5.5 6.0 9.0 basic-11.0 12.0 18.0 24.0 36.0 48.0 54.0
no preamble-short
station-role root bridge
cca 75
concatenation
distance 2
antenna gain 14
infrastructure-client
bridge-group 1
bridge-group 1 port-protected
bridge-group 1 spanning-disabled
interface FastEthernet0
no ip address
no ip route-cache
full-duplex
bridge-group 1
bridge-group 1 spanning-disabled
interface BVI1
ip address 10.1.254.252 255.255.255.248
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ip default-gateway 10.1.254.249
ip http server
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ip radius source-interface BVI1
radius-server attribute 32 include-in-access-req format %h
radius-server vsa send accounting
control-plane
bridge 1 route ip
Site 2 :
aaa new-model
aaa group server radius rad_eap
aaa group server radius rad_mac
aaa group server radius rad_acct
aaa group server radius rad_admin
aaa group server tacacs+ tac_admin
aaa group server radius rad_pmip
aaa group server radius dummy
aaa authentication login eap_methods group rad_eap
aaa authentication login mac_methods local
aaa authorization exec default local
aaa accounting network acct_methods start-stop group rad_acct
aaa session-id common
dot11 activity-timeout client default 99999
dot11 activity-timeout repeater default 99999
dot11 activity-timeout workgroup-bridge default 99999
dot11 activity-timeout bridge default 99999
dot11 ssid yyyy
authentication open
infrastructure-ssid
bridge irb
interface Dot11Radio0
bandwidth inherit
no ip address
no ip route-cache
ssid yyyy
short-slot-time
cca 75
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speed basic-1.0 basic-2.0 basic-5.5 6.0 9.0 basic-11.0 12.0 18.0 24.0 36.0 48.0 54.0
station-role workgroup-bridge
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keepalive 9999
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bridge-group 1 port-protected
bridge-group 1 spanning-disabled
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no ip route-cache
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bridge-group 1 spanning-disabled
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ip address 10.1.254.253 255.255.255.248
no ip route-cache
ip default-gateway 10.1.254.249
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Hi Sanjay,
Nothing is jumping out from the config all seems fairly standard. Points more to an RF problem.
Can you post the error logs/messages from the radios.
How much clearence above obstacles do you have between the link? At that distance on 2.4GHz there should be around 6m free space.
What antennas are you using? Have you performed a spectrum analysis at either end of the link to determine potential interference on the channel used?
From each end could run the following command and post the output:
show dot11 stat cli
show dot11 carrier busy
Thanks
Mat

1310 Root Bridge will not Authenticate with 350 Non Root Bridge

I've exhausted myself solving this issue.
I have a 1310 set as a root bridge using WEPS. I have a 350 set as a non root bridge/without clients, also using WEPS (they both use the same SSID)
The 350 will not authenticate to the 1310. After doing a Carrier Busy Test, it is clear the 350 see's the 1310 with signal strengh of 100 percent.
(I have a test lab setup in my office)
If I make the 350 the Root Bridge and the 1310 the Non Root, The 1310 will authenticate to the 350.
I hoping someone else has seen this problem and can enlighten me.
Thank you.

I have successfully configured a 1310 Bridge as a Root Bridge and a BR350 Bridge and a Non Root Bridge/with Clients. I also had to force the 1310 to operate at 11MB only.
As soon as I make the BR350 Bridge a Non Root Bridge/without Clients, the authentication is dropped between the two.
I was hoping I could transition to the 1310 one unit at a time since I have over a dozen 350's to replace.

AP1200 as Root Bridge: Accept wireless clients or not?

Cisco's docs precisely contradict themselves on this topic. In some places they state clearly that configuring an AP1200 as a root bridge means it will NOT accept connections from normal wireless clients. In other places they state just as clearly that in root bridge mode an AP1200 WILL accept connections from both non-root bridges and normal wireless clients.
Which is correct?

Yes, I discovered that after setting up several units and running some experiments. At first all I saw were the options offered in the "express setup" area. The root-bridge choice there says nothing about wireless clients, and the help screen it invokes says it won't work. But on the radio interface config screen the option you mention is offered and ITS help screen notes wireless clients will be accepted (as its name implies).
The telnet interface offers all the options as well.
I can confirm that it does work: In root-bridge with wireless client mode the unit will accept associations from non-root bridges, other AP1230's in WGB mode, and even non-Cisco clients.
The testing continues... thanks!

Non-root bridge association problem

I have an installation using Cisco 1242 Access Points (IOS) as bridges
in 5Ghz band, and as AP in 2,4 GHz band. Sometimes I get problems
with the non-root bridges, after mains outage, they will not
associate to the root bridge. Command "dot11 do 1 carrier busy"
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Hi Frank,
I think I have found the reason of my troubles. It is the following configuration command:
(interface Dot11Radio1)
world-mode dot11d country CZ outdoor
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Regards
Frantisek Opravil

Wireless Root Bridge - Non Root Bridge

I've been reading a lot about bridge configuration for wireless AP but i cannot make it work the following scenario:
PC -- ethernet port --> Non-Root-Bridge -----------> Root Bridge ---------> Switch
vlan111                     native 18 - vlan111           native 18 - vlan111      vlan native 18,111
Its pinging fine between switch and Non-Root. But when i put vlan111 on Non-Root the two AP's stop responding to the network.
What am i doing wrong? Plz i need some help!! I have two 1242.
------------------------ Root Config ----------------------
dot11 syslog
dot11 vlan-name JGS111 vlan 111
dot11 vlan-name JGS18 vlan 18
dot11 ssid WGB
   vlan 18
   authentication open
   guest-mode
   infrastructure-ssid
username Cisco password 7 047802150C2E
bridge irb
interface Dot11Radio0
no ip address
no ip route-cache
ssid WGB
station-role root bridge
infrastructure-client
interface Dot11Radio0.18
encapsulation dot1Q 18 native
no ip route-cache
bridge-group 1
bridge-group 1 spanning-disabled
interface Dot11Radio0.111
encapsulation dot1Q 111
no ip route-cache
bridge-group 111
bridge-group 111 spanning-disabled
interface Dot11Radio1
no ip address
no ip route-cache
shutdown
dfs band 3 block
channel dfs
station-role root
bridge-group 1
bridge-group 1 subscriber-loop-control
bridge-group 1 block-unknown-source
no bridge-group 1 source-learning
no bridge-group 1 unicast-flooding
bridge-group 1 spanning-disabled
interface FastEthernet0
no ip address
no ip route-cache
duplex auto
speed auto
interface FastEthernet0.18
encapsulation dot1Q 18 native
no ip route-cache
bridge-group 1
bridge-group 1 spanning-disabled
interface FastEthernet0.111
encapsulation dot1Q 111
no ip route-cache
bridge-group 111
bridge-group 111 spanning-disabled
interface BVI1
ip address 10.1.8.50 255.255.255.0
no ip route-cache
ip default-gateway 10.1.8.254
ip http server
no ip http secure-server
ip http help-path http://www.cisco.com/warp/public/779/smbiz/prodconfig/help/eag
bridge 1 route ip
------------- Non-Root-Bridge -------------
ot11 syslog
dot11 vlan-name JGS111 vlan 111
dot11 vlan-name JGS18 vlan 18
dot11 ssid WGB
   vlan 18
   authentication open
   guest-mode
   infrastructure-ssid
username Cisco password 7 14341B180F0B
bridge irb
interface Dot11Radio0
no ip address
no ip route-cache
ssid WGB
station-role non-root bridge
infrastructure-client
interface Dot11Radio0.18
encapsulation dot1Q 18 native
no ip route-cache
bridge-group 1
bridge-group 1 spanning-disabled
interface Dot11Radio0.111
encapsulation dot1Q 111
no ip route-cache
bridge-group 111
bridge-group 111 spanning-disabled
interface Dot11Radio1
no ip address
no ip route-cache
shutdown
dfs band 3 block
channel dfs
station-role root
bridge-group 1
bridge-group 1 subscriber-loop-control
bridge-group 1 block-unknown-source
no bridge-group 1 source-learning
no bridge-group 1 unicast-flooding
bridge-group 1 spanning-disabled
interface FastEthernet0
no ip address
no ip route-cache
duplex auto
speed auto
interface FastEthernet0.18
encapsulation dot1Q 18 native
no ip route-cache
bridge-group 1
bridge-group 1 spanning-disabled
interface FastEthernet0.111
encapsulation dot1Q 111
no ip route-cache
bridge-group 111
bridge-group 111 spanning-disabled
interface BVI1
ip address 10.1.8.51 255.255.255.0
no ip route-cache
ip default-gateway 10.1.8.254
ip http server
no ip http secure-server
ip http help-path http://www.cisco.com/warp/public/779/smbiz/prodconfig/help/eag
bridge 1 route ip

Try this:
interface Dot11Radio0.18
encapsulation dot1Q 18 native
no ip route-cache
bridge-group 1
bridge-group 1 subscriber-loop-control
bridge-group 1 block-unknown-source
no bridge-group 1 source-learning
no bridge-group 1 unicast-flooding
bridge-group 1 spanning-disabled
interface Dot11Radio0.111
encapsulation dot1Q 111
no ip route-cache
bridge-group 111
bridge-group 111 subscriber-loop-control
bridge-group 111 block-unknown-source
no bridge-group 111 source-learning
no bridge-group 111 unicast-flooding
bridge-group 111 spanning-disabled
interface FastEthernet0.18
encapsulation dot1Q 10 native
no ip route-cache
bridge-group 1
no bridge-group 1 source-learning
bridge-group 1 spanning-disabled
interface FastEthernet0.111
encapsulation dot1Q 111
no ip route-cache
bridge-group 111
no bridge-group 111 source-learning
bridge-group 111 spanning-disabled
Make sure your switchort is setup similar
interface GigabitEthernet0/7
description 1242 AP Bridge
switchport trunk encapsulation dot1q
switchport trunk native vlan 18
switchport trunk allowed vlans 18,111
switchport mode trunk
Thanks,
Scott
Help out other by using the rating system and marking answered questions as "Answered"

How Root bridge notifies it Topology change ?

Hi Friends ..
when there is any topology change in non-root bridge , it will generate the TCN bpdu and it will send to all bridges , once root bridge sends the TC bpdu it will flush out the mac table in 15 seconds. What happens when there is a topology change in the root bridge itself ? Will it directly starts the TC bpdu or it will also start the TCN bpdu ?

My personal guess is that there will be a STP recalculation and not simple TCN frame exchange. If a link on a designated port fails, then that port will no longer be in a forwarding state. And given the fact that a root bridge has Designated Ports which are in a forwarding state, then logically an election might take place.

Root Bridge Configuration

Hei,guys. As i got from the Cisco Official documents that the cmd to configure a root bridge has two styles. one is to set the switch to be root directly, and the other is to deploy the priority of the switch. However, I am confused by the cmd.
Switch(config)#spanning-tree Vlan 1 root primary
why should mention the Vlan 1 in the cmd. if it is the native vlan or other reasons?

Wei,
A gross simplification but perhaps helpful to you:
Use Rapid PVST+ if you have at most tens of VLANs and the entire network is based on Cisco switches
Use MSTP if you have hundreds of VLANs or the network is composed of Cisco and non-Cisco switches
Do not either use or activate STP. Both Rapid PVST+ and MSTP will automatically downgrade their operation to STP if they detect an old neighbor on a per-port basis while retaining their advantages on remaining ports.
A good reading can be found here:
http://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cfa.shtml
http://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cfc.shtml
http://blog.ine.com/2008/07/17/pvst-explained/
http://blog.internetworkexpert.com/2008/07/27/mstp-tutorial-part-i-inside-a-region/
http://blog.ine.com/2008/09/24/mstp-tutorial-part-ii-outside-a-region/
Best regards,
Peter

STP Loop after root bridge reload

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