多项选择题 A brand new network application is required for the Acme Company, and they are considering the use of a connectionless service. What are the characteristics of a connectionless service?（）

单项选择题 The Testking Corporation consists of the head office in New York with its regional offices in: Chicago, Detroit, Philadelphia, Toronto, and Atlanta. These offices need to be connected in a WAN, and Testking wishes to do this via a hub and spoke arrangement that will utilize packet-switched technology.Which one of the WAN technologies below would be the best choice for Testking?（）

单项选择题 The TestKing network is subnetted using 29 bits for the subnet mask. Which wild card mask should be used to configure an extended access list to permit or deny access to an entire subnetwork?（）