What is the difference between a School Resource Officer (SRO) and a School Security Officer (SSO)?

SRO == School Resource Officer: A deputy/officer of a local law enforcement agency who is uniformed, armed, possesses arrest powers and who is assigned to a Virginia middle or high school where he/she enforces the law, instructs law-related education classes, advises on crime prevention, investigates crime and serves as mentor and role model.

SSO == School Security Officer: A person hired by a local school board, who usually wears a uniform, does not carry a gun, may detain but not arrest crime suspects, and serves mainly to safeguard occupants of their assigned school.