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hydemoore_84718's avatar
hydemoore_84718
Icon for Nimbostratus rankNimbostratus
Dec 19, 2008

BIG-IP Spanning-tree behavior question

Hello.

 

Now I'm designing four-back style website

 

loadalancing site.

 

 

In F5 explanation,STP behavior is described

 

 

"A list of Spanning Tree Protocol modes. The difference between STP_MODE_TYPE_DISABLED and

 

STP_MODE_TYPE_PASSTHROUGH is that the pass-through mode forwards spanning tree bridge

 

protocol data units (BPDUs) received on any interface to all other interfaces, whereas

 

the disabled mode discards them."

 

Source:http://devcentral.f5.com/wiki/default.aspx/iControl.Networking

 

 

However, my company boss says the pass-through mode STP behaves IN THE SAME

 

VLAN SEGMENTS.

 

 

Which is the true answer?

2 Replies

  • Hamish's avatar
    Hamish
    Icon for Cirrocumulus rankCirrocumulus

    However, my company boss says the pass-through mode STP behaves IN THE SAME

     

    VLAN SEGMENTS.

     

    \

     

     

    Sorry... I don't understand this statement? Behaves in the same VLAN segments?

     

     

    basically the difference between the two is that STP_MODE_TYPE_DISABLED just drops BPDU's without forwarding, and STP_MODE_TYPE_PASSTHROUGH just forwards them... But I'm not sure what your statement form your boss is trying to say... Is he saying they do the same thing? Because if you're bridging two connections back to the same VLAN they certainly don't behave the same. if you bridge with STP_MODE_TYPE_DISABLED you'll probably end up with a bridging loop...

     

     

     

  •  

    I think your boss was asking you if F5 is forwarding BPDUs to all vlans or only within the vlan where BPDU was received? On that depends how flexible you are creating redundand links.

     

    1. In case of the common STP the second link between two devices will be blocked even if every link belongs to different vlan.

     

    2. In case of "per vlan STP" you can have redundand link for every vlan.

     

     

    I would also like to know the answer to that question. Actually, I'm going to test it in the lab this week.