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

If all OSPF routers in a single area are configured with the same priority value,what value dose a router use for the ODPF router ID in the absence of a loopback interface?（）

While troubleshooting a network problem,a technician discovers that the current copy of the Cisco IOS is outdated and needs to be updated.Which of the following commands would the technician issue to replace the Cisco router IOS with the newer version?（）

What is the default administrative distance of OSPF?（）

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?（）

When you are troubleshooting an ACL issue on a router,which command can help you to verify which interfaces are affected by the ACL?（）

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

An administrator must assign static IP addresses to the servers in a network.For network 192.168.20.24/29, the router is assigned the first usable host address while the sales server is given the last usable host address. Which of the following should be entered into the IP propertied box for the sales server?（）

What is the result of issuing the frame-relay map ip 192.168.1.2 202 broadcast command?（）

What is the subnetwork address for a host with the IP address 201.100.5.68/28?（）