MST Loop Effect Question

[Cloudy]

i have some question

if loop occur on some vlan. it will effect all vlan on same instance or not ? or effect to another instance ?

[Rolf Fischer · Accepted solution]

The scope of a bridging loop is normally the broadcast domain, which is a single VLAN. But if it results in the maloperation of one switch, the whole LAN can be affected.           

STP's purpose is to prevent bridging loops, so with STP enabled, a loop should no occur.

The former standard-based STP versions (802.1D, RSTP) prevent the occurence of bridging loops on a per-port basis regardless of the VLAN(s) assigned to a port; the Cisco proprietary versions do that on a per-VLAN basis and with MSTP it's done on a per-instance basis. The ST topology and the status of the instance applies to all VLANs mapped to that instance.

Instance 0 is a special case, because it also interacts with other regions/boundaries if they exist.

Hope that helps

Rolf