单项选择题
A. The authentication needs to be changed to PAP for both routers.
B. The serial IP addresses of routers are not on the same subnet.
C. The username/password combination is incorrectly configured.
D. The router names are incorrectly configured.
单项选择题 What kind of message does a PING send out to test connectivity?（）
单项选择题 The Testking router is running RIP as the routing protocol, and the IP routing table is displayed below: Gateway of last resort is 10.1.2.2 to network 0.0.0.0 10.0.0.0/24 is subnetted, 2 subnets R 10.1.3.0 [120/1] via 10.1.2.2, 00:00:00, Serial0/0 C 10.1.2.0 is directly connected, Serial0/0 C 10.1.5.0 is directly connected, Serial0/1 C 10.1.6.0 is directly connected, FastEthernet0/0 R* 0.0.0.0/0 [120/1] via 10.1.5.5, 00:00:00, Serial0/1 Based on the output above, if an administrator pings host 10.1.8.5 from host 10.1.6.100, how will the router TestkingA process the ICMP packets?（）
单项选择题 You work as a network engineer at TestKing.com. TestKing users have noticed extremely slow network performance, intermittent connectivity, and connection loss. After entering the show interfaces command, you notice that the Ethernet interface is configured as 100 Mbps full-duplex and that there is evidence of late collisions. What could be the cause of this problem?（）
