For acceptable voice calls, the packet error rate should be less than（）%

多项选择题What are three primary activities in the cycle of building an enterprise security strategy?（）

A. activity audit
B. administration
C. policy establishment
D. technology implementation

多项选择题Which two of these are recommended practices with trunks? （）

A. use ISL encapsulation
B. use 802.1q encapsulation
C. set ISL to desirable and auto with encapsulation negotiate to support ILS protocol negotiation
D. use VTP server mode to support dynamic propagation of VLAN information across the network
E. set DTP to desirable and desirable with encapsulation negotiate to support DTP protocol negotiation.

单项选择题When is the site-to-site remote access model appropriate? （）

A. for multiple ISDN connections
B. for modem concentrated dial-up connections
C. for a group of users in the same vicinity sharing a connection
D. for use by mobile users

多项选择题Which two design concerns must be addressed when designing a multicast implementation?（）

A. only the low-order 23 bits of the MAC address are used to map IP addresses
B. only the low-order 24 bits of the MAC address are used to map IP addresses
C. only the high-order 23 bits of the MAC address are used to map IP addresses
D. only the low-order 23 bits of the IP address are used to map MAC addresses
E. the 0x01004f MAC address prefix is used for mapping IP addresses to MAC addresses
F. the 0x01005e MAC address prefix is used for mapping IP addresses to MAC addresses

单项选择题Which routing protocol supports a flexible area structure using routing levels one and two?（）

A.OSPF
B.EIGRP
C.IS-IS
D.BGP