best way to prevent and avoid network loop?

[jeje1g]

Hi guy,
to prevent loop between to ports of the same switch/stack, we can use spanning tree.

But I want to know if there is a way to prevent a loop which is on a micro switch (like d'link or netgear) without STP enabled.

The use of rate-limit allow to the network to survive, but is there a mecanism to avoid this kind of loop?


thx

[Michael McNamara]

You can use STP/RSTP on a switch and it will detect a loop between any two switch ports regardless of what device is creating the loop. We use rate-limiting to prevent the switch software from going mad during a broadcast storm and/or loop event. The rate-limiting occurs in hardware so the software is protected from all the traffic it needs to "examine". In case where rate-limiting is not being used you'll often find that even after you've resolve the original "loop" you'll need to reboot the switch to make it happy again.

Good Luck!

[jeje1g]

So RSTP can prevent from this kind of loop (see attached file) ?

[Michael McNamara]

Indirectly, yes.

You'll need to have BPDU guard enabled... the switch will see it's own STP BPDU and will disable the port per the BPDU guard configuration.

Good Luck!