https://www.cisco.com/c/dam/global/zh_cn/solutions/industry/segment_sol/enterprise/programs_for_large_enterprise/pdf/sln/cisco_sba_sln_teleworking_asa5505deploymentguide-aug2012_chn.pdf https://www.cisco.com/c/en/us/support/security/asa-5505-adaptive-security-appliance/model.html https://www.cisco.com/c/dam/global/zh_cn/products/collateral/