Dynamic table sharing of memory space within a network device

Abstract

A network device for processing data on a data network includes a port interface configured to receive a data packet from a data network and to send a processed data packet to an egress port of the plurality of ports, a packet evaluation module configured to parse the received data packet and modify the received data packet to form the processed data packet and a search engine configured to perform searches of lookup tables using parsed data packet values and to return search results to the packet evaluation module to assist in modifying the received data packet. At least one lookup table shares at least two different types of entries in that same at least one lookup table, where the search engine is configured to distinguish between the at least two different types of entries in that same at least one lookup table.

What is claimed is: 
     
         1 . A network device comprising:
 a tunnel parser configured to determine whether tunneling is being employed by checking at least one received packet for inner and outer tags;   a tunnel type determiner configured to determine a tunnel type being employed by the at least one received packet based on a first set of one or more values included in the at least one received packet; and   a port determiner configured to determine at least one egress port via which to send the at least one received packet based on a second set of one or more values included in the at least one received packet.   
     
     
         2 . The network device of  claim 1 , further comprising a port interface configured to receive the at least one received packet from a data network and to send the at least one received packet to one or more egress ports. 
     
     
         3 . The network device of  claim 2 , further comprising the one or more egress ports. 
     
     
         4 . The network device of  claim 1 , further comprising a parser configured to parse fields of the at least one received data packet. 
     
     
         5 . The network device of  claim 1 , further comprising a parser FIFO configured to maintain a length(s) of the at least one received data packet. 
     
     
         6 . The network device of  claim 5 , further comprising a packet evaluation module configured to forward the at least one received data packet to both the tunnel parser and the parser FIFO to maintain a same packet order. 
     
     
         7 . The network device of  claim 1 , further comprising:
 a lookup table including:
 entries of a first type for determining an egress port via which to send received data packets of a first type; and 
 entries of a second type for determining an egress port via which to send received data packets of a second type; 
   wherein the port determiner is configured to determine the at least one egress port by checking the lookup table.   
     
     
         8 . The network device of  claim 1 , further comprising at least one ingress backpressure counter configured to determine whether the network device is in a backpressure state. 
     
     
         9 . The network device of  claim 8 , wherein the network device is configured to send at least one pause control frame based on the at least one ingress backpressure counter determining that the network device is in the backpressure state. 
     
     
         10 . The network device of  claim 1 , wherein the tunnel type determiner is configured to determine the tunnel type by checking the first set of one or more values against at least one preconfigured table. 
     
     
         11 . A method performed by a network device, the method comprising:
 determining whether tunneling is being employed by checking at least one received packet for inner and outer tags;   determining a tunnel type being employed by the at least one received packet based on a first set of one or more values included in the at least one received packet; and   determining at least one egress port via which to send the at least one received packet based on a second set of one or more values included in the at least one received packet.   
     
     
         12 . The method of  claim 11 , further comprising receiving the at least one received packet from a data network. 
     
     
         13 . The method of  claim 12 , further comprising sending the at last one packet via one or more egress ports. 
     
     
         14 . The method of  claim 11 , further comprising parsing fields of the at least one received data packet. 
     
     
         15 . The method of  claim 11 , further comprising maintaining a length(s) of the at least one received data packet. 
     
     
         16 . The method of  claim 15 , further comprising forwarding the at least one received data packet to both a tunnel parser and a parser FIFO to maintain a same packet order. 
     
     
         17 . The method of  claim 11 , further comprising determining at least one egress port by checking a lookup table. 
     
     
         18 . The method of  claim 11 , further comprising determining whether the network device is in a backpressure state. 
     
     
         19 . The method of  claim 18 , further comprising sending at least one pause control frame based on the determining that the network device is in the backpressure state. 
     
     
         20 . A network device comprising:
 means for determining whether tunneling is being employed by checking at least one received packet for inner and outer tags;   means for determining a tunnel type being employed by the at least one received packet based on a first set of one or more values included in the at least one received packet; and   means for determining at least one egress port via which to send the at least one received packet based on a second set of one or more values included in the at least one received packet.