thinQmaster Virtual testing partner Adaptive practice exams that find your weak spots and drill them. Every answer explained. From $69
Enroll

thinQmaster

Find your exam

Five questions free, before you decide.

Step 1 · choose a vendor

In one of our camps? Your practice exams come with the tuition — they are on your study page already.

Routing & Switching · Advanced

Internal Spanning Tree (IST)

MST instance 0, which carries BPDUs for the region and connects it to the Common and Internal Spanning Tree (CIST).

Definition

All VLANs not mapped to another instance belong to the IST. Only IST BPDUs are sent; MSTI information is carried as M-records inside them.

Example

spanning-tree mst 0 priority 4096

Exam tip

MST sends one BPDU containing all instance information, not a BPDU per instance.

Related terms