US6014380A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mechanism for packet field replacement in a multi-layer distributed network element
Assignee: Oracle America Inc
•
Filing: 1997-06-30
•
Granted: 2000-01-11
•
Expires: 2017-06-30
Abstract
Abstract A multi-layer distributed network element for relaying packets according to known routing protocols. A distributed architecture of multiple subsystems delivers routing at wire-speed performance across subnetworks. Each subsystem includes a forwarding memory and an associated memory and is configured to identify unicast and multicast packets for routing purposes, modify the packets in hardware, including replace VLAN information, and forward the packets to the next hop. The routing decisions are made in the inbound subsystem, and packets and associated control information are forwarded, if necessary given the network topology, through a separate outbound subsystem. When packets traverse the internal links from one subsystem to another, encapsulation operations are conducted such as appending an additional cyclic redundancy code (CRC) to the packet before going through the internal link.
Inventors
- 👤 Ariel Hendel
- 👤 Shimon Muller
- 👤 Louise Yeung
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:10
CPC Classifications
H; H04; H04L; H04L49/00; H04L49/30; H04L49/3009; H04L9/00; H04L9/40; H04L49/25; H04L49/35; H04L49/351; H04L49/354; H04L69/00; H04L69/22
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
240 words
In a switch comprising a plurality of switch elements, an apparatus for selectively performing header field replacement of packets communicated between two switch elements, comprising: a cascading output process (COP) located in a first switch element and configured to receive a packet, said packet comprising a header, data and cycle redundancy code (CRC), said COP further configured to receive control information and modify the packet by prepending control information to the packet, said control information providing information regarding a type of the packet, said COP further configured to output the modified packet; an output interface located in the first switch element, said output interface coupled to receive the modified packet and is configured to selectively generate a CRC to append to the modified packet, said output interface further configured to output the modified packet; an input interface located in a second switch element and configured to receive the packet output by the output interface of the first switch element, check frame validity of the packet using the appended CRC, and strip the appended CRC from the packet; a cascading input process (CIP) located in the second switch element and coupled to the input interface, said CIP configured to strip the control information to provide the control information to the second switch element to enable the second switch element to selectively modify the header of the packet in accordance with the control information prior to output from the second switch element.
Claim 2
Dependent Claim
240 words
In a switch comprising a plurality of switch elements, an apparatus for selectively performing header field replacement of packets communicated between two switch elements, comprising: a cascading output process (COP) located in a first switch element and configured to receive a packet, said packet comprising a header, data and cycle redundancy code (CRC), said COP further configured to receive control information and modify the packet by prepending control information to the packet, said control information providing information regarding a type of the packet, said COP further configured to output the modified packet; an output interface located in the first switch element, said output interface coupled to receive the modified packet and is configured to selectively generate a CRC to append to the modified packet, said output interface further configured to output the modified packet; an input interface located in a second switch element and configured to receive the packet output by the output interface of the first switch element, check frame validity of the packet using the appended CRC, and strip the appended CRC from the packet; a cascading input process (CIP) located in the second switch element and coupled to the input interface, said CIP configured to strip the control information to provide the control information to the second switch element to enable the second switch element to selectively modify the header of the packet in accordance with the control information prior to output from the second switch element.
Claim 3
Dependent Claim
172 words
The switch as set forth in claim 1, wherein said CIP is further configured to output the packet and the control information to indicate additional modification of the packet prior to output from the switch; said second switch element further comprising; an output port process (OPP) configured to receive the packet and the control information, said OPP configured, in response to said control information, to selectively generate at least one control signal to notify that the packet is to be modified prior to output from the switch and to output a selectively modified packet; an output interface, said output interface coupled to receive the at least one control signal and the selectively modified packet and is configured to output a packet from the switch that corresponds to the selectively modified input packet, said output interface further configured to selectively modify, in response to the at least one control signal, at least one header field and the CRC of the selectively modified packet prior to transmission of the output packet from the switch.
Claim 4
Dependent Claim
53 words
The apparatus as set forth in claim 1, wherein said control information comprises a field to indicate that the source address field of the header is to be replaced prior to output of the modified input packet by the second switch element, said field set when the input packet is to be routed.
Claim 5
Dependent Claim
25 words
The apparatus as set forth in claim 2, wherein the control signals selectively indicate generation of a CRC and a replacement of a source address.
Claim 6
Dependent Claim
72 words
The apparatus as set forth in claim 2, wherein the output interface of the second switch element is configured to insert the address of the output interface in a source address field of the header in response to the receipt of the at least one control signal indicating replacement of the source address, and to generate a CRC in response to the at least one control signal indicating regeneration of the CRC.
Claim 7
Dependent Claim
39 words
The apparatus as set forth in claim 2, wherein the OPP is further configured to strip off the CRC during transmission of the modified input packet to the output interface if the output interface is to generate the CRC.
Claim 8
Dependent Claim
15 words
The apparatus as set forth in claim 1, wherein the output interface is a MAC.
Claim 9
Dependent Claim
21 words
The apparatus as set forth in claim 2, wherein the at least one control signal comprises a replace -- sa signal.
Claim 10
Dependent Claim
36 words
The apparatus as set forth in claim 2, wherein the at least one control signal comprises a state of a NO -- CRC bit in a control word transmitted to the output interface by the OPP.
Claim 11
Dependent Claim
58 words
The apparatus as set forth in claim 1, wherein the switch supports virtual local area networks (VLANs) and the control information comprises an indication of whether the packet is tagged with VLAN information as it arrived in the first switch element, and whether the packet arrived tagged but has been modified and tags are not to be used.
Claim 12
Dependent Claim
118 words
The apparatus as set forth in claim 2, wherein said OPP determines whether to strip a VLAN tag field of the packet and send a control signal to the output interface to regenerate and append a CRC according to the following table: ______________________________________
regenerate
dont.sub.-- tag
tag.sub.-- enable
orig.sub.-- tag
mod.sub.-- tag
strip.sub.-- tag
CRC
______________________________________
1 x 0 x Y N
1 x 1 x Y N
0 0 0 x Y N
0 0 1 x Y Y
0 1 0 x N Y
0 1 1 0 N N
0 1 1 1 N Y
______________________________________ wherein tag -- enable is a network variable indicative that a network receiving node does not support VLAN routing.
Claim 13
Dependent Claim
39 words
The apparatus as set forth in claim 1, wherein the packet further comprises a preamble and interpacket gap which is reduced in size in order to append the CRC and prepend the control information without slowing down data rates.
Claim 14
Dependent Claim
153 words
In a switch comprising a plurality of switch elements, a method for selectively performing header field replacement of packets communicated between two switch elements of the plurality of switch elements, comprising: modifying a packet in a first switch element by prepending control information to the packet, said control information providing information regarding a type of the packet; generating a cycle redundancy code (CRC) in the first switch element to append to the modified packet to produce an encapsulated packet; said first element communicating the encapsulated packet to a second switch element; checking frame validity of the encapsulated packet received at the second switch element; stripping the appended CRC and the control information from the encapsulated packet; providing the control information to the second switch element to enable the second switch element to selectively modify a header of the packet in accordance with the control information prior to output from the second switch element.
Claim 15
Dependent Claim
153 words
In a switch comprising a plurality of switch elements, a method for selectively performing header field replacement of packets communicated between two switch elements of the plurality of switch elements, comprising: modifying a packet in a first switch element by prepending control information to the packet, said control information providing information regarding a type of the packet; generating a cycle redundancy code (CRC) in the first switch element to append to the modified packet to produce an encapsulated packet; said first element communicating the encapsulated packet to a second switch element; checking frame validity of the encapsulated packet received at the second switch element; stripping the appended CRC and the control information from the encapsulated packet; providing the control information to the second switch element to enable the second switch element to selectively modify a header of the packet in accordance with the control information prior to output from the second switch element.
Claim 16
Dependent Claim
67 words
The method as set forth in claim 13, further comprising the steps of: said second switch element selectively generating at least one control signal to notify that the packet is to be modified prior to output from the switch; selectively modifying in response to the at least one control signal, at least one header field and a CRC of the packet prior to output from the switch.
Claim 17
Dependent Claim
50 words
The method as set forth in claim 13, wherein said control information comprises a field to indicate that the source address field of the header is to be replaced prior to output of the packet from the second switch element, said field set when the packet is to be routed.
Claim 18
Dependent Claim
25 words
The method as set forth in claim 14, wherein the control signals selectively indicate generation of a CRC and a replacement of a source address.
Claim 19
Dependent Claim
63 words
The method as set forth in claim 14 further comprising the steps of: inserting an address of the output interface in a source address field of the header in response to receipt of the at least one control signal indicating replacement of the source address; and generating a CRC in response to the at least one control signal indicating regeneration of the CRC.
Claim 20
Dependent Claim
24 words
The method as set forth in claim 17, further comprising the step of stripping off the CRC if a CRC is to be generated.
Claim 21
Dependent Claim
49 words
The method as set forth in claim 13, wherein the switch supports virtual local area networks (VLANs) and the control information comprises an indication of whether the packet is tagged as it arrived, whether the packet arrived tagged but has been modified and tags are not to be used.
Claim 22
Dependent Claim
109 words
The apparatus as set forth in claim 19, further comprising the step of determining whether to strip a VLAN tag and regenerate and append a CRC to the packet according to the following table: ______________________________________
regenerate
dont.sub.-- tag
tag.sub.-- enable
orig.sub.-- tag
mod.sub.-- tag
strip.sub.-- tag
CRC
______________________________________
1 x 0 x Y N
1 x 1 x Y N
0 0 0 x Y N
0 0 1 x Y Y
0 1 0 x N Y
0 1 1 0 N N
0 1 1 1 N Y
______________________________________ wherein tag -- enable is a network variable indicative that a receiving node does not support VLAN routing.
Claim 23
Dependent Claim
40 words
The method as set forth in claim 13, wherein the packet further comprises a preamble and interpacket gap, said method further comprising the step of reducing the packet in size by reducing a size of the preamble and interpacket gap.
References Cited (Backward Citations)
US4652874A
Cited
US4850042A
Cited
US4807111A
Cited
US4899333A
Cited
US4922503A
Cited
US4933938A
Cited
US5220562A
Cited
US5278830A
Cited
US5210746A
Cited
US5301333A
Cited
US5309437A
Cited
US5231633A
Cited
US5150358A
Cited
US5481540A
Cited
US5251205A
Cited
US5293379A
Cited
US5500860A
Cited
US5392432A
Cited
US5461624A
Cited
US5343471A
Cited
US5720032A
Cited
US5742760A
Cited
US5457681A
Cited
US5425028A
Cited
US5291482A
Cited
US5490252A
Cited
US5410540A
Cited
US5649109A
Cited
US5410722A
Cited
US5459714A
Cited
US5485578A
Cited
US5386413A
Cited
US5477537A
Cited
US5455820A
Cited
US5426736A
Cited
US5394402A
Cited
US5450399A
Cited
US5555405A
Cited
US5610905A
Cited
US5515376A
Cited
US5473607A
Cited
US5422838A
Cited
US5485455A
Cited
US5790546A
Cited
US5570365A
Cited
US5535202A
Cited
US5459717A
Cited
US5602841A
Cited
US5572522A
Cited
US5461611A
Cited
US5583981A
Cited
US5600641A
Cited
US5751967A
Cited
US5640605A
Cited
US5619500A
Cited
US5594727A
Cited
US5490139A
Cited
US5675741A
Cited
US5784573A
Cited
US5726977A
Cited
US5745048A
Cited
US5706472A
Cited
US5561666A
Cited
US5633865A
Cited
US5619661A
Cited
US5734865A
Cited
US5636371A
Cited
US5651002A
Cited
US5754540A
Cited
US5691984A
Cited
US5740175A
Cited
US5757771A
Cited
US5684800A
Cited
US5754801A
Cited
US5740375A
Cited
US5781549A
Cited
US5724358A
Cited
US5764634A
Cited
US5740171A
Cited
US5764636A
Cited
US5742604A
Cited
US5757795A
Cited
US5802052A
Cited
US5748905A
Cited
WO1998013016A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-01-10 | 2003-07-12 | 2004-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-01-10 | 2007-07-12 | 2008-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-01-10 | 2011-07-12 | 2012-01-11 | $7700.00 | Window Closed / Lapsed |