Which of the following should the network administrator troubleshoot FIRST in order to rectify the issue?

A company has attempted to introduce a new major network segment to allow growth in capacity. On the core switch, a GBIC was used to interconnect with a newly placed downstream distribution switch for the first time. Soon after this implementation, a network flood and an outage occurred between the core and new distribution network modules.

Which of the following should the network administrator troubleshoot FIRST in order to rectify the issue?
A . Check for switching loops between core and distribution switches.
B . Check whether an incorrect VLAN has been assigned to the new distribution switch.
C . Check for inconsistent or missing routes between the core and distribution switches.
D . Check whether the GBIC was set to multi-mode instead of single-mode SF

Answer: A