US6674769B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Simultaneous searching of layer 3 policy filter and policy cache in a network switch port
Assignee: GlobalFoundries Inc
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Filing: 2000-03-07
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Granted: 2004-01-06
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Expires: 2020-03-07
Abstract
Abstract A network switch, configured for performing layer 2 and layer 3 switching in an Ethernet (IEEE 802.3) network without blocking of incoming data packets, includes network switch ports, each including a policy filter configured for obtaining layer 3 and layer 4 information from a received layer 2 frame. The layer 3 information and the layer 4 information are used to determine a policy identifier that specifies a layer 3 switching operation to be performed on the received layer 2 frame. Each network switch port also includes a policy cache that caches portions of the layer 3 information and the corresponding policy identifier. The policy filter and the policy cache are then simultaneously searched for subsequent layer 3 frames to find the appropriate policy; if the appropriate policy is located in the policy cache, the searching operation is completed, enabling the network switch port resources to begin searching operations for another packet. Hence, policy search performance can be improved by execution of simultaneous search operations in the policy filter and the policy cache.
Inventors
- 👤 Somnath Viswanath
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:12
CPC Classifications
H; H04; H04L; H04L49/00; H04L49/60; H04L49/604; H04L45/00; H04L45/74; H04L45/742
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
153 words
A method in a network switch, the method comprising: receiving a first layer 2 frame at a network switch port, the first layer 2 frame including layer 3 information and layer 4 information that specify payload data characteristics within the first layer 2 frame; determining by a policy filter in the network switch port a policy identifier for the first layer 2 frame based on the layer 3 information and the layer 4 information, the policy identifier specifying a layer 3 switching operation to be performed on the first layer 2 frame; storing first information identifying the first layer 3 information and the layer 4 information, and the policy identifier, in a policy cache in the network switch port; receiving a second layer 2 frame at the network switch port; and simultaneously searching, for a second policy identifier for the second layer 2 frame, by the policy filter and within the policy cache.
Claim 2
Independent Claim
153 words
A method in a network switch, the method comprising: receiving a first layer 2 frame at a network switch port, the first layer 2 frame including layer 3 information and layer 4 information that specify payload data characteristics within the first layer 2 frame; determining by a policy filter in the network switch port a policy identifier for the first layer 2 frame based on the layer 3 information and the layer 4 information, the policy identifier specifying a layer 3 switching operation to be performed on the first layer 2 frame; storing first information identifying the first layer 3 information and the layer 4 information, and the policy identifier, in a policy cache in the network switch port; receiving a second layer 2 frame at the network switch port; and simultaneously searching, for a second policy identifier for the second layer 2 frame, by the policy filter and within the policy cache.
Claim 3
Dependent Claim
32 words
The method of claim 1 , wherein the simultaneously searching step includes supplying an abort signal to the policy filter in response to detecting the second policy identifier in the policy cache.
Claim 4
Dependent Claim
37 words
The method of claim 2 , wherein the determining step includes generating the first information by generating hash keys for the layer 3 and layer 4 information, respectively, and combining the hash keys into a single signature.
Claim 5
Dependent Claim
32 words
The method of claim 3 , wherein the determining step further includes searching a signature table within the network switch for the policy identifier using the single signature as a search key.
Claim 6
Dependent Claim
24 words
The method of claim 4 , wherein the storing step includes storing the single signature and the corresponding policy identifier into the policy cache.
Claim 7
Dependent Claim
42 words
The method of claim 4 , wherein the generating step includes generating the hash keys for each of an Internet Protocol (IP) source address, IP destination address, Transmission Control Protocol/User Datagram Protocol (TCP/UDP) source port, TCP/UDP destination port, and a protocol number.
Claim 8
Dependent Claim
37 words
The method of claim 1 , wherein the determining step includes generating the first information by generating hash keys for the layer 3 and layer 4 information, respectively, and combining the hash keys into a single signature.
Claim 9
Dependent Claim
24 words
The method of claim 7 , wherein the storing step includes storing the single signature and the corresponding policy identifier into the policy cache.
Claim 10
Dependent Claim
32 words
The method of claim 8 , wherein the determining step further includes searching a signature table within the network switch for the policy identifier using the single signature as a search key.
Claim 11
Dependent Claim
44 words
The method of claim 9 , wherein the generating step includes generating the hash keys for at least two of an Internet Protocol (IP) source address, IP destination address, Transmission Control Protocol/User Datagram Protocol (TCP/UDP) source port, TCP/UDP destination port, and a protocol number.
Claim 12
Dependent Claim
35 words
The method of claim 10 , wherein the generating step includes generating the hash keys for each of the IP source address, IP destination address, TCP/UDP source port, TCP/UDP destination port, and the protocol number.
Claim 13
Dependent Claim
51 words
The method of claim 11 , wherein the simultaneously searching step includes generating the single signature for the second layer 2 frame, and simultaneously searching the signature table by the policy filter and the policy cache for the second policy identifier using the single signature for the second layer 2 frame.
Claim 14
Dependent Claim
193 words
An integrated network switch configured for executing layer 3 switching decisions, the integrated network switch comprising: an index table that includes addresses of layer 3 switching entries that specify respective layer 3 switching operations based on selected data fields within a received data packet, the index table also including for each address entry a corresponding entry signature representing a combination of the selected data fields hashed according to a prescribed hashing operation; and network switch ports each comprising: (1) a policy filter configured for obtaining layer 3 information and layer 4 information, corresponding to the selected data fields, from a received layer 2 frame and determining, based on generation of a second entry signature from the obtained layer 3 information and layer 4 information, a policy identifier that specifies the layer 3 switching operation to be performed on the corresponding layer 2 frame, and (2) a policy cache configured for storing the policy identifier having been determined by the policy filter and the corresponding entry signature, the network switch port simultaneously searching using the policy filter and the policy cache for determining the policy identifier for each corresponding subsequently received layer 2 frame.
Claim 15
Dependent Claim
193 words
An integrated network switch configured for executing layer 3 switching decisions, the integrated network switch comprising: an index table that includes addresses of layer 3 switching entries that specify respective layer 3 switching operations based on selected data fields within a received data packet, the index table also including for each address entry a corresponding entry signature representing a combination of the selected data fields hashed according to a prescribed hashing operation; and network switch ports each comprising: (1) a policy filter configured for obtaining layer 3 information and layer 4 information, corresponding to the selected data fields, from a received layer 2 frame and determining, based on generation of a second entry signature from the obtained layer 3 information and layer 4 information, a policy identifier that specifies the layer 3 switching operation to be performed on the corresponding layer 2 frame, and (2) a policy cache configured for storing the policy identifier having been determined by the policy filter and the corresponding entry signature, the network switch port simultaneously searching using the policy filter and the policy cache for determining the policy identifier for each corresponding subsequently received layer 2 frame.
Claim 16
Dependent Claim
48 words
The switch of claim 13 , wherein the policy filter generates the second entry signature by combining hash keys for at least two of an Internet Protocol (IP) source address, IP destination address, Transmission Control Protocol/User Datagram Protocol (TCP/UDP) source port, TCP/UDP destination port, and a protocol number.
Claim 17
Dependent Claim
39 words
The switch of claim 13 , wherein the policy filter aborts searching of the index table in response to an abort signal indicating detection of the policy identifier for a corresonding received layer 2 frame in the policy cache.
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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) | 2007-01-05 | 2007-07-07 | 2008-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2011-01-05 | 2011-07-07 | 2012-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2015-01-05 | 2015-07-07 | 2016-01-06 | $7700.00 | Window Closed / Lapsed |