Patent ID: 8379649
Filing Date: 2013-02-19
Classification: H04L

Abstract:
1. A forwarding apparatus including multiple VPN routing and forwarding tables (VRFs) configured to individually have routing tables provided for respective virtual private networks (VPNs), wherein each of the routing tables is structured to record a communication route of a packet based on a layer 3 address specifying an address of the packet and a forwarding destination layer 3 address specifying a forwarding destination of the packet from an assigned VRF or a VRF assigned to the routing table, as well as an extranet communication route of forwarding the packet from the assigned VRF to another VRF, the forwarding apparatus comprising: a first storage module configured to store a layer 2-layer 3-integrated forwarding table structured to record at least one entry, wherein each entry includes VRF information and a packet destination layer 3 address as search conditions for specifying the forwarding destination of the packet, as well as a forwarding destination layer 3 interface, a forwarding destination layer 3 address, and a forwarding destination layer 2 address as search results, when a correspondence relation of the forwarding destination layer 3 address to the forwarding destination layer 2 address is unresolved for an entry, the entry including specific data representing an ‘unresolved’ state of the forwarding destination layer 2 address; a route introducer configured to introduce each communication route, which is recorded in each of the routing tables, into the layer 2-layer 3-integrated forwarding table; an address resolving module configured to introduce a correspondence relation of a layer 3 address to a layer 2 address of an adjacent device as an adjacent device layer 3 address-to-layer 2 address correspondence relation with regard to the forwarding destination layer 3 interface of an entry recorded in the layer 2-layer 3-integrated forwarding table, into the layer 2-layer 3-integrated forwarding table; and a forwarding destination identification module configured to search the layer 2-layer 3-integrated forwarding table with a layer 3 address specifying an address recorded in the packet as a search key to specify the forwarding destination of the packet, in response to presence of an entry, which includes a direct route using a packet destination layer 3 address as the forwarding destination layer 3 address and the VRF information as the search condition for specifying the forwarding destination of the packet that is different from a VRF assigned to the forwarding destination layer 3 interface, in the layer 2-layer 3-integrated forwarding table, the address resolving module utilizing VRF information identical with the VRF information as the search condition to introduce the adjacent device layer 3 address-to-layer 2 address correspondence relation into the layer 2-layer 3-integrated forwarding table; a second storage module configured to store a direct route VRF table that is structured to record at least one entry, wherein each entry includes a correspondence relation of a layer 3 interface and a layer 3 address to a VRF identifier group, wherein the address resolving module searches the direct route VRF table with a layer 3 interface connected to the adjacent device and the layer 3 address of the adjacent device as search keys to obtain a VRF identifier group and uses each VRF identifier of the obtained VRF identifier group for the VRF information as the search condition of specifying the forwarding destination of the packet to introduce the adjacent device layer 3 address-to-layer 2 address correspondence relation into the layer 2-layer 3-integrated forwarding table.