Article Title: Service Credit
Here is an informative article from OPM if you are a federal employee seeking to increase your time toward federal retirement by adding your military service. The article details the eligibility requirements, what service is applicable, FERS and CSRS answers, deposit/redeposit for service, procedures for paying a deposit or redeposit, procedures for paying, and Military under USERRA.
Article Source: www.opm.gov