Abstract: A variable valve actuation device for an engine includes a rocker arm mechanism, a camshaft, an actuation mechanism and a blocking mechanism. The rocker arm roller can slide on a roller shaft so as to have two operating positions, a first cam and a second cam which are adjacent are provided on the camshaft, the rocker arm mechanism is actuated, based on the different operating positions of the rocker arm roller, by the first cam or the second cam, respectively, to enable the engine to have two valve lifts, a control cam is further provided on one side of the first cam or the second cam, the control cam can actuate the blocking mechanism, and the rocker arm roller is blocked from switching in a switching prohibited portion of the first cam and the second cam, and is allowed to switching in a non-switching prohibited portion.

Abstract: A variable valve actuation device for an engine includes a rocker arm mechanism, a camshaft, an actuation mechanism and a blocking mechanism. The rocker arm roller can slide on a roller shaft so as to have two operating positions, a first cam and a second cam which are adjacent are provided on the camshaft, the rocker arm mechanism is actuated, based on the different operating positions of the rocker arm roller, by the first cam or the second cam, respectively, to enable the engine to have two valve lifts, a control cam is further provided on one side of the first cam or the second cam, the control cam can actuate the blocking mechanism, and the rocker arm roller is blocked from switching in a switching prohibited portion of the first cam and the second cam, and is allowed to switching in a non-switching prohibited portion.

Abstract: Dynamically selecting a DHCP server for a DHCP client terminal device may include triggering, by a network device, an authentication performed by an authentication server on a DHCP client terminal device user when receiving a DHCP packet for requesting a configuration parameter sent from a DHCP client terminal device, receiving, by the network device, an identity of a DHCP server designated by the authentication server for the DHCP client terminal device user when the DHCP client terminal device user passes the authentication, and establishing an entry for user information of the DHCP client terminal device user and the identity of the designated DHCP server, and matching, by the network device, the user information carried in a packet with established entries when receiving the packet subsequently sent from the DHCP client terminal device, and forwarding the packet using the identity of the DHCP server in the entry matching the user information.

Abstract: Dynamically selecting a DHCP server for a DHCP client terminal device, according to an example, includes: triggering, by a network device with a DHCP relay function, an authentication performed by an authentication server on a DHCP client terminal device user when receiving a DHCP packet for requesting a configuration parameter sent from a DHCP client terminal device; receiving, by the network device, an identity of a DHCP server designated by the authentication server for the DHCP client terminal device user when the DHCP client terminal device user passes the authentication, and establishing an entry for user information of the DHCP client terminal device user and the identity of the designated DHCP server; and matching, by the network device, the user information carried in a packet with established entries when receiving the packet subsequently sent from the DHCP client terminal device, and forwarding the packet using the identity of the DHCP server in the entry matching the user information.