View all questions & answers for the NSE 5 - FortiSwitch 7.6 Administrator Exam Materials exam
Question 42 Discussion
Comments
Selected Answers: B, C
Network administrators often prefer to use LAGs and MCLAGs to enable redundancy and increase network bandwidth. Although you can achieve the same outcome using Multiple Spanning Tree Protocol (MSTP) and mapping VLANs to different instances, the setup is not as simple.
A spanning tree sees LAGs and MCLAGs as a single logical interface. Also, LAGs and MCLAGs are considered up if at least one of their links is up. This means that changes in the state of the links in a LAG or MCLAG do not trigger a spanning tree topology change unless all the links in the LAG or MCLAG come down. In addition, in the case of an MCLAG peer group, the MCLAG clients see the two peers as a single switch participating in STP.
The example on this slide shows four interconnected switches. Switch 1 and Switch 2 are MCLAG peers. Switch 3 is the MCLAG client. Switch 4 is connected to Switch 3 using a regular LAG. STP sees the MCLAG peers as a single switch, and the uplinks on Switch 3 and Switch 4 are treated as single interfaces. (PAGE 186 IMAGE FOR REFERENCE).
Spanning Tree Protocol bases its decisions on logical interfaces and logical bridge identities rather than raw physical links. When a LAG is configured, multiple physical links are bundled into a single logical interface, so STP treats that connection as one port. This is why uplinks from Switch 3 and Switch 4 are seen as single interfaces. In an MCLAG setup, two physical switches are configured to operate as peers and present themselves as a single logical switch to downstream devices. The inter chassis link allows the peer switches to synchronize forwarding state, MAC learning, and STP information so they share one bridge identity. Because of this coordination, STP does not see Switch 1 and Switch 2 as separate devices but as one logical switch, which prevents loops while still allowing active active forwarding.
PAGE: 44&186 | fortiswitch 7.6 admin guide
Refer to the exhibit. How does Spanning Tree Protocol (STP) see MCLAG and LAG if they are configured based on the physical view shown in the exhibit? (Choose two answers)
Brave-Dump Clients Votes