Tri-colour data packet counting for tri-colour marking policies
View Patent ↗The invention is directed to counting data packets marked according to tri-color marking techniques. Packets of a packet flow that are marked according to a three color (or tri-color) marking scheme are counted using a counter implemented on a ternary content addressable memory (TCAM). Advantages of some embodiments of the invention are to enable the use of generic and cost-efficient TCAMs to quickly obtain the counts of all three colors of packets in such a packet flow. These counts can be used to provide detailed statistics on characteristics of the packet flow, which can be useful for debugging and accounting purposes.
1. A method of configuring a tri-color packet counter for counting packets of a data packet flow marked according to a tri-color marking scheme, comprising the steps of:
determining an identifier for the flow;
ascertaining if there is a Ternary Content Accessible Memory (TCAM) entry for the identifier;
ascertaining, responsive to there being said TCAM entry, if there are three TCAM counters associated with the entry; and
configuring, responsive to there being fewer than three such TCAM counters, one or more TCAM counters associated with the entry so there are a total of at least three TCAM counters associated with the entry.
2. The method of claim 1 , wherein ascertaining if there is a TCAM entry comprises configuring, responsive to there not being said entry, a TCAM entry with the identifier.
3. The method of claim 2 , wherein determining comprises ascertaining if there is a tri-color marking flow policy for the flow and responsive to there not being such a policy, configuring said policy in a flow policy storage.
4. The method of claim 1 , wherein configuring comprises configuring the one or more counters such that two of the at least three counters are configured on a first TCAM and a third of the at least three counters is configured on a second TCAM.
5. The method of claim 3 wherein configuring said policy in the flow policy storage comprises configuring said policy on either the first or second TCAM.
6. The method of claim 1 , further comprising determining if any of said counters should be read and, responsive to an affirmative determination, reading such counters.
7. The method of claim 1 , further comprising determining if any of said counters should be reset and, responsive to an affirmative determination, resetting such counters.
8. The method of claim 2 , determining a tri-color marking flow policy associated with the identifier, wherein the tri-color marking flow policy is a srTCM flow policy.
9. An apparatus for counting packets of a data packet flow marked according to a tri-color marking scheme, the apparatus comprising:
a plurality of ternary content addressable memories (TCAMs), each TCAM having a plurality of TCAM entries;
a flow identifier configured to determine an identifier for the flow and ascertain if there is a TCAM entry for the identifier; and
a TCAM controller configured to:
ascertain, responsive to there being said TCAM entry, if there are three TCAM counters associated with the entry; and
configure, responsive to there being fewer than three such TCAM counters, one or more TCAM counters associated with the entry so there are a total of at least three TCAM counters associated with the entry.
10. The apparatus of claim 9 , wherein the TCAM controller is further configured to configure a TCAM entry with the identifier responsive to there not being said entry.
11. The apparatus of claim 10 further comprising a flow policy storage, wherein the flow identifier is further configured to ascertain if there is a tri-color marking flow policy for the flow and responsive to there not being such a policy, configure said policy in a flow policy storage.
12. The apparatus of claim 9 , wherein the TCAM controller is configured to configure the one or more counters such that two of the at least three counters are configured on a first TCAM and a third of the at least three counters is configured on a second TCAM.
13. The apparatus of claim 11 wherein configuring said policy in the flow policy storage comprises configuring said policy on either the first or second TCAM.
14. The apparatus of claim 9 , further comprising a packet processor, wherein the TCAM controller is further configured to determine if any of said counters should be read and, responsive to an affirmative determination, reading such counters and sending a packet count of each counter to the packet processor.
15. The apparatus of claim 9 , wherein the TCAM controller is further configured to determine if any of said counters should be reset and, responsive to an affirmative determination, reset said counters.
16. The apparatus of claim 10 , wherein the TCAM converter is further configured to determine a tri-color marking flow policy associated with the identifier, wherein the tri-color marking flow policy is a srTCM flow policy.