Question: In the event of a suspected Network Element (NE) Certification Authority (CA) key compromise, what action is REQUIRED for existing intra-security domain connections established shortly before the suspected compromise but after the suspected time of compromise?
Option 1: These connections shall be torn down and re-established with new certificates.
Option 2: These connections may be left intact but must undergo additional security checks.
Option 3: No action is required for these connections; only new connections need new certificates.
Option 4: The decision to tear down or maintain these connections is at the operator's discretion.
Explanation: If an NE CA key is suspected to be compromised, existing intra-security domain connections formed after the suspected time of compromise must be torn down to prevent potential security breaches. They should be re-established with new, secure certificates.