Disable Spanning Tree on Catalyst 6509 & Catalyst 3750

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Dec 14th, 2009
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Can i disable STP on Catalyst 6509 & Catalyst 3750 globally ?  If yes command ?

Can i disable STP on Catalyst 6509 & Catalyst 3750 per interface ? If yes command ?

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c_wombles Mon, 12/14/2009 - 23:19
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Yes you can.


You can disable STP per VLAN with

switch(config)# no spanning-tree vlan vlan-id


Useful if you want to default ports to use portfast. Then you can have STP enabled for uplinks.
swithc(config)#spanning-tree portfast default


To disable spanning-tree per port you can use

switch(config-if)#spanning-tree portfast


Make sure your topology is free of loops when enabling this, as you'll create yourself a world of pain.


some links for more information.

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.1E/native/command/reference/S1.html#wp1180500


Information of configuring STP

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/catos/5.x/configuration/guide/spantree.html

csawest.dc Mon, 12/14/2009 - 23:29
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Dear satish,


Yes it is possible but before pl give me the details.


Regards.


Vaibhav.

Giuseppe Larosa Mon, 12/14/2009 - 23:55
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Hello Satish,


even if it  is possible, I strongly recommend to avoid this: STP is still useful even if the device is standalone to detect when a cable connects two ports of the same switch.


STP is there to prevent bridging loops, disabling STP does not mean that bridging loops can not occur even if someone calls them STP loops they are not caused by STP.


if there is a question of STP scalability (number of STP instances running on C3750 for example) you can minimize STP instances running on a device using

switchport trunk allowed vlan

VTP pruning does not provide STP instances minimization.


If the problem is interoperability with other vendors you can consider MST 802.1s.


if you are providing L2 services to a customer and you don't want to participate in customer's STP you can use


switchport bpufilter enable


in port mode


Hope to help

Giuseppe

vvasisth Tue, 12/15/2009 - 02:56
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"no spanning-tree vlan " this will definatly disable STP but its not recommended as it wont detect any layer 2 loop and makes your network more prone to loops and failures.


Regards,

varun

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