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Re: Spanning Tree Protocol - Disabled by Default????

Julio Cassettez
Occasional Contributor

Spanning Tree Protocol - Disabled by Default????

I was deploying a few HP switches the other day (an 8212zl and a couple of 5406zl switches) running the latest software (K.15.04.0003) and was shocked to see that STP is disabled by default?!?!?!?!

Please tell me I'm wrong. If I'm correct why on earth would this be a default setting? This is crazy dangerous!

I googled it and someone mentioned an HP instructor said it was because of Appletalk or Netware giving up on address acquisition if STP was enabled. So instead of just doing something like Cisco's portfast* option, they just disabled it by default all together.

Check this link out:

// begin HP quote
Q: When I power on my PC, I get the message "a file server could not be found." How do I fix that?

A: There are several workarounds available:
1.Disable Spanning Tree on the switch (if Spanning Tree is not needed, i.e. no loops in the network topology).

In the Fall of 1998, HP released switch firmware with an enhancement to resolve this timing problem between Novell and STP. The enhancement allows users to configure Spanning Tree so that it does not go through the 4 states, on a port-by-port basis. Instead, for those configured ports, Spanning Tree will immediately begin forwarding packets to and from the port. This allows Novell clients to communicate with the server as soon as the network card (NIC) is enabled. After that, the switch continues to listen for and send Spanning Tree packets on those configured ports. This protects the user who might inadvertently connect a hub or switch to that port and create a network loop—Spanning Tree will detect the loop after a short time, since the port listens for and sends STP packets on that port.

// end HP quote
Richard Brodie_1
Honored Contributor

Re: Spanning Tree Protocol - Disabled by Default????

Julio Cassettez
Occasional Contributor

Re: Spanning Tree Protocol - Disabled by Default????

Thanks for responding. I read that post. But that's like a car company saying "We aren't really sure if seat belts or air bags are better, so we won't give you either by default".

To me it makes absolutely no sense. They should just default to good old fashioned 802.1d STP (seat belts). All the newer versions of STP are backward compatible (air bags will function just fine along side seat belts). So ship the product with the good old fashioned version enabled. That's good enough to prevent most disasters.

I'm trying to give HP the benefit of the doubt. Surely they must have a better reason. Otherwise they should be embarrassed.

Please post here if you agree!!! Maybe they can change the default mode in upcoming releases.
New Member

Re: Spanning Tree Protocol - Disabled by Default????

Yeah, protocols are set of rules between two transaction. Even it helps to transmit the data from one place to another.