A network administrator is planning a network installation for a large organization.The design requires 100 separate subnetworks,so the company has acquired a Class B network address.What subnet mask will provide the 100 subnetworks required, if 500 usable host addresses are required per subnet?（）

Which command is used to display the collection of OSPF link states?（）

Which encapsulation type is a Frame Relay encapsulation type that is supported by Cisco routers?（）

After the show ip route command has been entered,the follwing routes are displayed.Which route will not be entered into the routing table of a neighboring router?（）

Which device might be installed at a branch office to enable and manage an IPsec site-to-site VPN?（）

At which layer of the OSI model dose PPP perform?（）

Which cisco ios command can help to determine the timing of various debug events,relative to each other,when you are debugging a complicated router issue?（）

Which statement describes the rule of split horizon?（）

A network administrator needs to configure a serial link between the main office and a remote location.The router at the remote office is a non-cisco router. How should the network administrator configure the serial interface of the main office router to make the connection?（）

Which command encrypts all plaintext passwords?（）