Acme Company has offices around the country. With the use of Cisco Unified CallManager， the company has deployed a VoIP network in a multisite centralized configuration. Which IOS gateway feature should be deployed to enable VoIP devices to register with a local gateway and continue to function when the connection to the Cisco Unified CallManager is broken？ （）

A.VPN traffic needs to be classified based on the Layer2 header information
B.VPN traffic needs to be classified based on the IP precedence or DSCP
C.VPN traffic needs to be classified based on IP flow or Layer 3 information， such as source and destination IP address
D.VPN traffic with Authentication Header （AH） needs to preserve the ToS byte

A.the two methods of authentication using the WEP encryption are open and shared key
B.the 802.11 standard defines WEP security using 128-bit keys
C.WEP can provide stronger authentication through the use of LEAP， PEAP， or EAP-FAST
D.WEP is a scalable encryption solution that uses static keys for authentication
E.WEP security provides only one-way authentication
F.WEPv2 offers improved encryption by replacing the RC4 encryption mechanism with the AES （symmetric block cipher） mechanism

A.enabling modular QoS over Frame Relay
B.enabling Real-Time Transport Protocol （RTP） header compression
C.enabling distributed compressed Transmission Control Protocol
D.enabling latency and jitter reduction for Transmission Control traffic
E.enabling TCP header compression