Reason for sudden loss of BPDUs

[tiwariharish44]

Hi,

I was studying for my CCNP switch exam. During the topic of Loopguard, I came across "Due to sudden loss of BPDUs, a loop may be introduced in the network".

Now what is the exact technical reason for a switch to not receive the BPDUs from the neigbouring switch?

[Rolf Fischer]

Hi,

especially fiber connections can cause loops during unidirectional conditions; we normally prefer UDLD to prevent this from happening because it works independantly from the STP port state/role (directly on link-layer), but LoopGuard could also detect such conditions on non-designated ports.

But in addition LoopGuard can also detect situations in which a neighbor switch does not send BPDUs due to misconfiguration, high CPU load (STP is a software process), implementation errors, etc.

So both features/enhancements have their own reason for existence.

HTH
Rolf