Avoiding recirculation of data packets in a network device

Abstract

In one embodiment, a method is provided. The method includes receiving a data packet via an ingress interface of the network device. The method also includes determining whether the data packet comprises an Internet Protocol version 4 (IPV4) or an Internet Protocol version 6 (IPV6) packet. The method further includes in response to determining that the packet comprises an IPV4 packet, identifying a first entry in an adjacency table. The first entry is associated with an address prefix. The address prefix is associated with first Internet Protocol (IP) address of the data packet. The first entry indicates a next hop for the data packet. The adjacency table comprises a second entry associated with the address prefix. The method further includes forwarding the packet to the next hop indicated by the first entry in the adjacency table, via an egress interface of the network device.

What is claimed is: 
     
         1 . A method of forwarding data in a network device, comprising:
 receiving a data packet via an ingress interface of the network device;   determining whether the data packet comprises an Internet Protocol version 4 (IPV4) or an Internet Protocol version 6 (IPV6) packet;   in response to determining that the packet comprises an IPV4 packet, identifying a first entry in an adjacency table, wherein:
 the first entry is associated with an address prefix; 
 the address prefix is associated with first Internet Protocol (IP) address of the data packet; 
 the first entry indicates a next hop for the data packet; and 
 the adjacency table comprises a second entry associated with the address prefix; 
 and 
   forwarding the packet to the next hop indicated by the first entry in the adjacency table, via an egress interface of the network device.   
     
     
         2 . The method of  claim 1 , wherein the next hop for the data packet comprises an IPV6 next hop. 
     
     
         3 . The method of  claim 2 , wherein the network device is unable to use an IPV6 access control list for the egress interface. 
     
     
         4 . The method of  claim 3 , wherein the network device is able to use an IPV4 access control list for the egress interface. 
     
     
         5 . The method of  claim 3 , wherein the network device recirculates IPV6 packets through the network device via a recirculation interface to use the IPV6 access control list. 
     
     
         6 . The method of  claim 5 , wherein the network device avoids recirculating the data packet through the network device by forwarding the packet to the next hop indicated by the first entry in the adjacency table. 
     
     
         7 . The method of  claim 1 , wherein identifying the first entry in the adjacency table comprises:
 identifying a third entry in a prefix match table, wherein the third entry comprises an indication of the first entry in the adjacency table.   
     
     
         8 . The method of  claim 1 , further comprising:
 determining whether an IPV6 access control list is used on the egress interface; and   in response to determining that the IPV6 access control list is used on the egress interface, creating the first entry and the second entry in the adjacency table.   
     
     
         9 . The method of  claim 1 , further comprising:
 in response to determining that the packet comprises an IPV6 packet, forwarding the packet to a second next hop indicated by the second entry in the adjacency table, via the egress interface of the network device.   
     
     
         10 . The method of  claim 1 , wherein the next hop comprises one or more of a next hop interface or a next hop network device. 
     
     
         11 . A network device, comprising:
 a memory to store data; and   a processing device coupled to the memory, the processing device to:
 receive a data packet via an ingress interface of the network device; 
 determine whether the data packet comprises an Internet Protocol version 4 (IPV4) or an Internet Protocol version 6 (IPV6) packet; 
 in response to determining that the packet comprises an IPV4 packet, identify a first entry in an adjacency table, wherein:
 the first entry is associated with an address prefix; 
 the address prefix is associated with first Internet Protocol (IP) address of the data packet; 
 the first entry indicates a next hop for the data packet; and 
 the adjacency table comprises a second entry associated with the address prefix; 
 and 
 
 forward the packet to the next hop indicated by the first entry in the adjacency table, via an egress interface of the network device. 
   
     
     
         12 . The network device of  claim 11 , wherein the next hop for the data packet comprises an IPV6 next hop. 
     
     
         13 . The network device of  claim 12 , wherein the network device is unable to use an IPV6 access control list for the egress interface. 
     
     
         14 . The network device of  claim 13 , wherein the network device is able to use an IPV4 access control list for the egress interface. 
     
     
         15 . The network device of  claim 13 , wherein the network device recirculates IPV6 packets through the network device via a recirculation interface to use the IPV6 access control list. 
     
     
         16 . The network device of  claim 15 , wherein the network device avoids recirculating the data packet through the network device by forwarding the packet to the next hop indicated by the first entry in the adjacency table. 
     
     
         17 . The network device of  claim 11 , wherein to identify the first entry in the adjacency table the processing device is further to:
 identify a third entry in a prefix match table, wherein the third entry comprises an indication of the first entry in the adjacency table.   
     
     
         18 . The network device of  claim 11 , further comprising:
 determining whether an IPV6 access control list is used on the egress interface; and   in response to determining that the IPV6 access control list is used on the egress interface, creating the first entry and the second entry in the adjacency table.   
     
     
         19 . The network device of  claim 11 , wherein the processing device is further to:
 in response to determining that the packet comprises an IPV6 packet, forward the packet to a second next hop indicated by the second entry in the adjacency table, via the egress interface of the network device.   
     
     
         20 . A non-transitory machine-readable medium having executable instructions to cause one or more processing devices to perform a method comprising:
 receiving a data packet via an ingress interface of a network device;   determining whether the data packet comprises an Internet Protocol version 4 (IPV4) or an Internet Protocol version 6 (IPV6) packet;   in response to determining that the packet comprises an IPV4 packet, identifying a first entry in an adjacency table, wherein:
 the first entry is associated with an address prefix; 
 the address prefix is associated with first Internet Protocol (IP) address of the data packet; 
 the first entry indicates a next hop for the data packet; and 
 the adjacency table comprises a second entry associated with the address prefix; 
 and 
   forwarding the packet to the next hop indicated by the first entry in the adjacency table, via an egress interface of the network device.