Need help with Spanning Tree issue

[joch2joch]

Hi,

We are trying to implement a web farm as depicted in the diagram. We were recommended to enable 'STP Fast Learning' on the relevant interfaces of the Cisco switches, but I noticed that Fast Learning is a global command, and not interface-specific.

Does anyone have any ideas?

Jo

[Roberto Salazar]

stp fast lerning command does not seem to exist for any of the cisco switches. You said you are able to do it on global mode? Can you post that command from global mode from the switch you are able to do it?

[joch2joch]

OOPS!! sorry...i believe i have mistyped it..:P

I was actually referring to the command 'UplinkFast', which I thought was related to'fast learning'

Thank you for the sanity check :)

[mahmoodmkl]

HI

To understand what uplinkfast does follow this link

http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a0080094641.shtml

Thanks

Mahmood

[ankurbhasin]

Hi Friend,

Yes UPLINK FAST is a global mode command and is not an individual interface command.

When you enable UplinkFast, it affects all VLANs on the switch. You cannot configure UplinkFast on an individual VLAN

Check this link

http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12120ea2/3550scg/swstpopt.htm#wp1032095

If you talk ot STP portfast command it is confiured on invidual interfaces.

HTH, if yes please rate the post.

Ankur

[Roberto Salazar]

Uplink fast is global only and from the drawing I do not see any switches that are dual homed in which uplink fast might be most useful.

Please see the link:

http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12225see/scg/swstpopt.htm#wp1031144

[joch2joch]

Hi,

If UplinkFast is not the solution, then what does it mean by 'fast learning'??

[ankurbhasin]

Hi Friend,

I am not sure what exactly you mean by fast learning cause I haven't read anything like that on cisco switches.

Talking about your web farm I think these are web servers if yes you can configure "spantree portfast" on interfaces where you have connected your web servers which is 3560A nd B switches.

HTH, if yes please rate the post.

Ankur

[Bobby Thekkekandam]

Ankur is correct. It is definitely a good idea to enable portfast for the switchports connected to the webservers. Additionally, it is recommended to configure the macro command "switchport host" which combines "spanning-tree portfast" with disabling DTP (trunk negotiation) and channeling.

See more on this here:

http://www.cisco.com/warp/public/473/53.shtml#Using_set_port_host_or_portfast_for

HTH,

Bobby

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