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US 7,412,507 B2Granted
Efficient cascaded lookups at a network node
AssigneeLucent Technologies Inc.
InventorsApoorv Saxena, Apurva Mehta
Life of this patent
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Abstract
Performing cascading lookups at a network node involves using first header information from a packet to search a first set of search criteria for a match, identifying a tag associated with the match, and using second header information from the packet and the tag to search a second set of search criteria for another match.
Claims24
A method for performing a lookup at a network node comprising:
- associating multiple entries in a first set of search criteria with a same tag, wherein said multiple entries correspond to different traffic profiles;
- and
- establishing a single entry in a second set of search criteria that provides associated data for said multiple entries in said first set of search criteria with said same tag, wherein said single entry in said second set of search criteria includes said tag as search criteria;
- using first header information from a packet to search a first set of search criteria for a first match;
- identifying said tag associated with said first match;
- using second header information from said packet and said tag to search a second set of search criteria for a second match.
3 more elements
A method for performing a lookup at a network node comprising:
- associating multiple entries in a L3 lookup table with a same tag, wherein said multiple entries correspond to different traffic profiles;
- and
- establishing a single entry in a L4 lookup table that provides associated data for said multiple entries in said L3 lookup table with said same tag, wherein said single entry in said L4 lookup table includes said tag as search criteria;
- searching said layer three (L3) lookup table comprising L3 table entries for an L3 table entry that matches L3 header information of a packet;
- identifying said tag associated with said L3 table entry;
- searching said layer four (L4) lookup table comprising L4 table entries for an L4 table entry that matches L4 header information of said packet and said tag.
3 more elements
A system for performing lookups at a network node, comprising:
- a first content addressable memory (CAM)-based lookup table that has associated data, said first CAM-based lookup table including a tag field as part of said associated data;
- a first lookup engine configured to receive first search keys related to packets and to search said first CAM-based lookup table using said first search keys;
- a second CAM-based lookup table that includes search criteria, said second CAM-based lookup table including a tag field as part of said search criteria;
- and
- a second lookup engine configured to receive second search keys related to said packets and to search said second CAM-based lookup table using said second search keys, wherein said second search keys include tags;
- wherein:
- multiple entries in said first CAM-based lookup table are associated with a same tag, wherein said multiple entries correspond to different traffic profiles;
- and
- a single entry in said second CAM-based lookup table is established that provides associated data for said multiple entries in said first CAM-based lookup table with said same tag, wherein said single entry in said second CAM-based lookup table includes said tag as search criteria.
6 more elements
A system for performing a lookup at a network node comprising:
- a first lookup engine configured to receive a first search key relating to a packet and to search a first lookup table using said first search key, said first lookup table comprising first lookup table search criteria entries, a first lookup table search criteria entry of said first lookup table search criteria entries being associated with a tag as a result field, wherein a match between said first search key and said first lookup table search criteria entry yields said tag;
- and
- a second lookup engine configured to receive a second search key relating to said packet, wherein said second search key includes said tag, said second lookup engine also configured to search a second lookup table using said second search key, said second lookup table comprising second lookup table search criteria entries, a second lookup table search criteria entry of said second lookup table search criteria entries including said tag as part of said search criteria for said second lookup table search criteria entry;
- wherein said first and second lookup tables are implemented in content addressable memory (CAM);
- wherein:
- multiple entries in said first lookup table are associated with a same tag, wherein said multiple entries correspond to different traffic profiles;
- and
- a single entry in said second lookup table is established that provides associated data for said multiple entries in said first lookup table with said same tag, wherein said single entry in said second lookup table includes said tag as search criteria.
5 more elements
Dependencies are inferred from the claim text.