US6606681B1
Expired / Lapsed
US
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Optimized content addressable memory (CAM)
Assignee: Cisco Technology Inc
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Filing: 2001-02-23
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Granted: 2003-08-12
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Expires: 2021-02-23
Abstract
Abstract A method and apparatus for realizing a content addressable memory. The content addressable memory including an associative memory portion including N entries, each entry including a key and an M-bit type indicator. The content addressable memory further including a random access memory portion. The random access memory portion includes K*N entries where a single key stored as an entry in the associative memory portion is mapped to K entries in the random access memory portion, where K is greater than 1.
Inventors
- 👤 Necdet Uzun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:42
CPC Classifications
H; H04; H04L; H04L45/00; H04L45/74; H04L45/745; H04L45/7453
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
196 words
A method for storing MAC addresses and MPLS labels in a content addressable memory, the content addressable memory including an associative portion and a random access portion, the associative portion including one or more entries each including a key, the random access portion for storing information relevant to each key, the method comprising: determining if a key is present in a first entry in the associative portion for a first context, either as a source address or destination address or both; locating a first key portion of the key to be associated with an MPLS label; checking first key portion for all other keys in the content addressable memory to see if the first key portion matches; if the first key portion does not match, marking the address in the associative portion of the first entry to indicate that the address is to be associated with a second context, the second context being an MPLS label; and adding information relevant to the second context and associated with the address to the random access portion including mapping the address to relevant information stored in the random access portion associated with the first context and the second context.
Claim 2
Independent Claim
196 words
A method for storing MAC addresses and MPLS labels in a content addressable memory, the content addressable memory including an associative portion and a random access portion, the associative portion including one or more entries each including a key, the random access portion for storing information relevant to each key, the method comprising: determining if a key is present in a first entry in the associative portion for a first context, either as a source address or destination address or both; locating a first key portion of the key to be associated with an MPLS label; checking first key portion for all other keys in the content addressable memory to see if the first key portion matches; if the first key portion does not match, marking the address in the associative portion of the first entry to indicate that the address is to be associated with a second context, the second context being an MPLS label; and adding information relevant to the second context and associated with the address to the random access portion including mapping the address to relevant information stored in the random access portion associated with the first context and the second context.
Claim 3
Dependent Claim
127 words
The method of claim 1 , further comprising: if the first key portion matches, locating a second key portion of the key to be associated with a second MPLS label; checking the second key portion for all other keys in the content addressable memory to see if the second key portion matches; if the second key portion does not match marking the address in the associative portion to indicate that the address is to be associated with a second context, the second context being an MPLS label; and adding information relevant to the second context and associated with the address to the random access portion including mapping the address to relevant information stored in the random access portion associated with the first context and the second context.
Claim 4
Dependent Claim
15 words
The method of claim 1 , wherein the first context corresponds to an Ethernet address.
Claim 5
Dependent Claim
14 words
The method of claim 1 , wherein the first entry includes two MPLS labels.
Claim 6
Independent Claim
207 words
An apparatus for storing MAC addresses and MPLS labels in a content addressable memory, the content addressable memory including an associative portion and a random access portion, the associative portion including one or more entries each including a key, the random access portion for storing information relevant to each key, the apparatus comprising: means for determining if a key is present in a first entry in the associative portion for a first context, either as a source address or destination address or both; means for locating a first key portion of the key to be associated with an MPLS label; means for checking the first key portion for all other keys in the content addressable memory to see if the first key portion matches; means for marking, if the first key portion does not match, the address in the associative portion of the first entry to indicate that the address is to be associated with a second context, the second context being an MPLS label; and means for adding information relevant to the second context and associated with the address to the random access portion including mapping the address to relevant information stored in the random access portion associated with the first context and the second context.
Claim 7
Independent Claim
207 words
An apparatus for storing MAC addresses and MPLS labels in a content addressable memory, the content addressable memory including an associative portion and a random access portion, the associative portion including one or more entries each including a key, the random access portion for storing information relevant to each key, the apparatus comprising: means for determining if a key is present in a first entry in the associative portion for a first context, either as a source address or destination address or both; means for locating a first key portion of the key to be associated with an MPLS label; means for checking the first key portion for all other keys in the content addressable memory to see if the first key portion matches; means for marking, if the first key portion does not match, the address in the associative portion of the first entry to indicate that the address is to be associated with a second context, the second context being an MPLS label; and means for adding information relevant to the second context and associated with the address to the random access portion including mapping the address to relevant information stored in the random access portion associated with the first context and the second context.
Claim 8
Dependent Claim
135 words
The apparatus of claim 5 , further comprising: means for locating, if the first key portion matches, a second key portion of the key to be associated with a second MPLS label; means for checking the second key portion for all other keys in the content addressable memory to see if the second key portion matches; means for marking, if the second key portion does not match, the address in the associative portion to indicate that the address is to be associated with a second context, the second context being an MPLS label; and means for adding information relevant to the second context and associated with the address to the random access portion including mapping the address to relevant information stored in the random access portion associated with the first context and the second context.
Claim 9
Dependent Claim
15 words
The apparatus of claim 5 , wherein the first context corresponds to an Ethernet address.
Claim 10
Dependent Claim
14 words
The apparatus of claim 5 , wherein the first entry includes two MPLS labels.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2006-08-11 | 2007-02-10 | 2007-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2010-08-11 | 2011-02-10 | 2011-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2014-08-11 | 2015-02-10 | 2015-08-12 | $7700.00 | Window Closed / Lapsed |