Abstract: In an embodiment, a network router includes plural interfaces and a chain walker which, upon receipt of a first protocol packet in a first interface, processes the packet by walking the packet through a decapsulation chain associated with the interface and the first protocol and an encapsulation chain associated with an identified second interface and identified second protocol. The walker passes the packet to elements of the decapsulation chain to produce a decapsulated packet. The walker passes the decapsulated packet to elements of an encapsulation chain to produce an encapsulated packet. Each chain includes at least one packet-processing element. An element receives the packet from the walker as processed by a previous element, the packet being further processed as appropriate. The walker, upon receipt of the first protocol packet, passes the packet to elements of a demultiplexer chain associated with the first interface to produce a demultiplexed packet.

Abstract: A network device provides services for multiple virtual private networks (VPNs) via one or more virtual hosts. For example, a router receives packets from multiple VPNs, and communicates the packets to a service card via a logical interface in accordance with a forwarding information base. A virtual host within the service card processes the packets and provides a service for the network device from which the packet was sent. The virtual host may, for example, provide print services for network devices within a corresponding VPN. The virtual host acts, in essence, as a print server within the corresponding VPN. In this manner, the router may eliminate the need for the customer associated with the VPN to maintain print servers within remote customer sites.

Abstract: A network device provides services for multiple virtual private networks (VPNs) via one or more virtual hosts. For example, a router receives packets from multiple VPNs, and communicates the packets to a service card via a logical interface in accordance with a forwarding information base. A virtual host within the service card processes the packets and provides a service for the network device from which the packet was sent. The virtual host may, for example, provide print services for network devices within a corresponding VPN. The virtual host acts, in essence, as a print server within the corresponding VPN. In this manner, the router may eliminate the need for the customer associated with the VPN to maintain print servers within remote customer sites.

Abstract: A method for processing packets in a router includes specifying operations on packets as chains of processing elements. Each chain is uniquely associated with one interface/protocol pair, and each processing element performs at least one function on a packet. An incoming packet is received, and processed, first by a demultiplexor element which determines the protocol of the next higher level used by the packet. Then, the packet is processed by the elements of a decapsulation chain associated with the interface on which the packet was received, and by the elements of an encapsulation chain associated with the interface on which the packet is to be transmitted. The demultiplexor element or operation passes the packet on to a decapsulation chain associated with the protocol and with the incoming interface, depending on protocol information contained in the incoming packet.

Abstract: A method for processing packets in a router includes specifying operations on packets as chains of processing elements. Each chain is uniquely associated with one interface/protocol pair, and each processing element performs at least one function on a packet. An incoming packet is received, and processed, first by a demultiplexor element which determines the protocol of the next higher level used by the packet. Then, the packet is processed by the elements of a decapsulation chain associated with the interface on which the packet was received, and by the elements of an encapsulation chain associated with the interface on which the packet is to be transmitted. The demultiplexor element or operation passes the packet on to a decapsulation chain associated with the protocol and with the incoming interface, depending on protocol information contained in the incoming packet.