9th Lecture - Networking

[kakatiya]

[quote author=k2s link=topic=243110.msg3040341#msg3040341 date=1317155045]
Spanning tree states :


State                            Forwards Data Frames?                  Learns MACs Based on                              Transitory or
                                                                                            Received Frames?                                        Stable State?

Blocking                                      No                                                No                                                    Stable
Listening                                    No                                                No                                                    Transitory
Learning                                      No                                                Yes                                                  Transitory
Forwarding                                  Yes                                                Yes                                                  Stable
Disabled                                      No                                                  No                                                    Stable
[/quote] is there any ocmmand to modify the states ?

[k2s]

When STP converges, a switch chooses transition interfaces from one state to another.
However, a transition from blocking to forwarding cannot be done immediately because an
immediate change to forwarding could temporarily cause frames to loop. To prevent these
temporary loops, STP transitions an interface through two intermediate interface states, as
follows:


■ Listening: Like the Blocking State, the interface does not forward frames. Old, now-
  incorrect MAC table entries are timed out during this state, because the old incorrect
  MAC table entries would be the root cause of the temporary loops.

■ Learning: Interfaces in this state still do not forward frames, but the switch begins to
  learn the MAC addresses of frames received on the interface.



STP moves an interface from Blocking to Listening, then to Learning, and then to
Forwarding State. STP leaves the interface in each interim state for a time equal to the
forward delay timer. As a result, a convergence event that causes an interface to change
from Blocking to Forwarding requires 30 seconds to transition from Blocking to
Forwarding. Additionally, a switch might have to wait MaxAge seconds before even
choosing to move an interface from Blocking to Forwarding state. Following the same
example shown in the last several figures, SW3 might wait MaxAge seconds before
deciding that it is no longer receiving the same root BPDU on its root port (20 seconds is
the default), and then wait 15 seconds each in Listening and Learning States on interface
Gi0/2, resulting in a 50-second convergence delay

[CaliStar]

%<>(

source : [url=http://www.cisco.com]www.cisco.com[/url]

[k2s]

[quote author=kakatiya link=topic=243110.msg3040365#msg3040365 date=1317155273]
is there any ocmmand to modify the states ?
[/quote]these states changed when an STP is run..... user / admin doesn't have option to change the states.......whereas, when a STP converges, u can surely issue the command " show span" to see the state changes for every 15-20 secs

[k2s]

[quote author=CaliStar link=topic=243110.msg3040381#msg3040381 date=1317155449]
%<>(

source : [url=http://www.cisco.com]www.cisco.com[/url]
[/quote] thankyou

see my 1st lecture
*7*^

[k2s]

[quote author=Kakateeyudu© link=topic=243110.msg3040290#msg3040290 date=1317154472]
cry@fl cry@fl cry@fl cry@fl cry@fl cry@fl cry@fl cry@fl cry@fl cry@fl  em ardam kavatla
[/quote] sSa_j@il

[k2s]

[img]http://lh3.ggpht.com/-VzVBmI6BcSQ/TmBTnWul7WI/AAAAAAAAD9s/2PDYlrB-gmA/Brahmi.gif[/img] evavru lera......

[ding]

[img]http://chalanachithram.com/discus/clipart2/chiru6.gif[/img]

[andala ramudu]

sSc_hidingsofa sSc_hidingsofa

[ToughGuy]

#~` #~` #~` nuvvu evvarini pattincukomaku ...vesthaane vundu

[k2s]

[quote author=!!!! FeRRo !!!! link=topic=243110.msg3040509#msg3040509 date=1317156992]
#~` #~` #~` nuvvu evvarini pattincukomaku ...vesthaane vundu
[/quote][img]http://i1142.photobucket.com/albums/n616/raves27/ahuti2.gif[/img]

[k2s]

Guys pls see this flash:

briefly explains about STP operation & root bridge election etc

[url=http://www.cisco.com/image/gif/paws/10556/spanning_tree1.swf]http://www.cisco.com/image/gif/paws/10556/spanning_tree1.swf[/url]

[robo]

F@!n

[ToughGuy]

[quote author=k2s link=topic=243110.msg3040513#msg3040513 date=1317157045]
[img]http://i1142.photobucket.com/albums/n616/raves27/ahuti2.gif[/img]
[/quote][img width=320 height=180]http://www.desigifs.com/sites/default/files/2wokq4i.gif?1290230355[/img]

[tom bhayya]

*=: