WIRE-SPEED PENDING INTEREST TABLE

1 . A method performed by a router, the method comprising:

receiving, at a first line card of the router, a request for content having a content identifier;

determining a second line card that is responsible for the content identifier;

switching the request for content to the second line card;

updating a pending interest table at the second line card based on the request for content.

2 . The method of claim 1 , wherein the step of determining a second line card comprises:

hashing the content identifier to obtain a content hash; and

performing a modulus operation on the content hash based on a number of line cards in the router.

3 . The method of claim 1 , wherein the step of updating the pending interest table comprises:

determining that the pending interest table does not include an entry for the content identifier;

creating a new pending interest table entry including the content identifier and the first line card; and

forwarding the request for content based on the content identifier.

4 . The method of claim 3 , further comprising: forwarding the request for content to a plurality of the line cards.

5 . The method of claim 1 , wherein the step of updating the pending interest table comprises:

determining that the pending interest table already includes an entry for the content; and

updating the pending interest table entry with the first line card.

6 . The method of claim 1 , further comprising:

receiving, at a third line card, data responsive to the request for content having the content identifier;

determining that the second line is responsible for the data based on the content identifier;

switching the data to the second line card;

looking up a pending interest table entry in the pending interest table based on the content identifier;

identifying the first line card that received a request for the content based on the pending interest table entry;

forwarding the data responsive to the request from the first line card; and

deleting the pending interest table entry from the pending interest table.

7 . The method of claim 6 , wherein the step of forwarding the data responsive to the request from the first line card comprises:

determining that a plurality of line cards, including the first line card, received a request for the content based on the pending interest table; and

multicasting the data responsive to the request from the plurality of line cards indicated by the pending interest table.

8 . The method of claim 1 , wherein the pending interest table is a d-left open-addressed hash-table.

9 . The method of claim 1 , wherein the pending interest table comprises a plurality of pending interest table entries, each entry including: a content identifier, an expiration time, a nonce, and a list of line cards.

10 . The method of claim 1 , further comprising:

storing a nonce included in the request for content in the pending interest table;

receiving a second request for the content having the content identifier;

determining that the second request includes the nonce stored in the pending interest table; and

determining that the second request has looped back to the router.

11 . A router for content based routing that receives a plurality of requests for contents, each including a content identifier, the router comprising:

a fabric switch; and

a plurality of line cards interconnected by the fabric switch, each line card comprising a network processor and a pending interest table configured to store entries for a subset of the requests defined by the content identifier,

wherein the network processor of a line card that receives a request is configured to determine which line card of the plurality of line cards is configured to process the received request based on the content identifier.

12 . The router of claim 11 , wherein the network processor is configured to hash the content identifier included in a received request and perform a modulus operation on the hash result to determine the line card configured to process the received request.

13 . The router of claim 11 , wherein the pending interest table comprises a plurality of pending interest table entries, each entry including: a content identifier, an expiration time, a nonce, and a list of line cards.

14 . The router of claim 11 , wherein the pending interest table of a line card is smaller than a cache of the network processor.

15 . The router of claim 11 , wherein the pending interest table is an open-addressed d-left hash table.

16 . The router of claim 11 , further comprising a forwarding table including a mapping of content identifiers to interfaces.

17 . The router of claim 16 , wherein each line card is configured to:

receive a request for content from a first line card via the fabric switch;

update the pending interest table of the line card with the content identifier and an identifier of the first line card; and

forward the request for content based on an interface indicated by the forwarding information base for the content identifier.

18 . The router of claim 17 , wherein each line card is further configured to:

receive content data responsive to a request for content, the content data including a content identifier; and

determine which line card of the plurality of line cards is configured to process the received content data based on the content identifier.

19 . The router of claim 18 , wherein each line card is further configured to:

receive the content data responsive to a request for content from the third line card via the fabric switch;

determine the first line card based on the content identifier and the pending interest table; and

forward the content data to the first line card.