DE69834823D1 - Paketvermittlungsvorrichtung und -verfahren mit zentraler Speicherarchitektur - Google Patents

Paketvermittlungsvorrichtung und -verfahren mit zentraler Speicherarchitektur

Info

Publication number
DE69834823D1
DE69834823D1 DE69834823T DE69834823T DE69834823D1 DE 69834823 D1 DE69834823 D1 DE 69834823D1 DE 69834823 T DE69834823 T DE 69834823T DE 69834823 T DE69834823 T DE 69834823T DE 69834823 D1 DE69834823 D1 DE 69834823D1
Authority
DE
Germany
Prior art keywords
packet switching
switching apparatus
central memory
memory architecture
architecture
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
DE69834823T
Other languages
English (en)
Other versions
DE69834823T2 (de
Inventor
Stephen R Haddock
Justin N Chueh
David K Parker
Herb Schneider
R Steven Smith
Erik R Swenson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Extreme Networks Inc
Original Assignee
Extreme Networks Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Extreme Networks Inc filed Critical Extreme Networks Inc
Application granted granted Critical
Publication of DE69834823D1 publication Critical patent/DE69834823D1/de
Publication of DE69834823T2 publication Critical patent/DE69834823T2/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/24—Traffic characterised by specific attributes, e.g. priority or QoS
    • H04L47/2441—Traffic characterised by specific attributes, e.g. priority or QoS relying on flow classification, e.g. using integrated services [IntServ]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/74—Address processing for routing
    • H04L45/745—Address table lookup; Address filtering
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/24—Traffic characterised by specific attributes, e.g. priority or QoS
    • H04L47/2416—Real-time traffic
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/50—Queue scheduling
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/50—Queue scheduling
    • H04L47/62—Queue scheduling characterised by scheduling criteria
    • H04L47/6215—Individual queue per QOS, rate or priority
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/50—Queue scheduling
    • H04L47/62—Queue scheduling characterised by scheduling criteria
    • H04L47/625—Queue scheduling characterised by scheduling criteria for service slots or service orders
    • H04L47/627—Queue scheduling characterised by scheduling criteria for service slots or service orders policing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L49/00—Packet switching elements
    • H04L49/35—Switches specially adapted for specific applications
    • H04L49/351—Switches specially adapted for specific applications for local area network [LAN], e.g. Ethernet switches
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L49/00—Packet switching elements
    • H04L49/30—Peripheral units, e.g. input or output ports
    • H04L49/3018—Input queuing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L49/00—Packet switching elements
    • H04L49/35—Switches specially adapted for specific applications
    • H04L49/351—Switches specially adapted for specific applications for local area network [LAN], e.g. Ethernet switches
    • H04L49/352—Gigabit ethernet switching [GBPS]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L49/00—Packet switching elements
    • H04L49/35—Switches specially adapted for specific applications
    • H04L49/354—Switches specially adapted for specific applications for supporting virtual local area networks [VLAN]
DE69834823T 1997-08-29 1998-08-28 Paketvermittlungsvorrichtung und -verfahren mit zentraler Speicherarchitektur Expired - Lifetime DE69834823T2 (de)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US5740297P 1997-08-29 1997-08-29
US57402P 1997-08-29
US09/016,017 US6295299B1 (en) 1997-08-29 1998-01-30 Data path architecture for a LAN switch
US16017 1998-01-30
PCT/US1998/017974 WO1999011036A1 (en) 1997-08-29 1998-08-28 Data path architecture for a lan switch

Publications (2)

Publication Number Publication Date
DE69834823D1 true DE69834823D1 (de) 2006-07-20
DE69834823T2 DE69834823T2 (de) 2006-12-21

Family

ID=26688064

Family Applications (1)

Application Number Title Priority Date Filing Date
DE69834823T Expired - Lifetime DE69834823T2 (de) 1997-08-29 1998-08-28 Paketvermittlungsvorrichtung und -verfahren mit zentraler Speicherarchitektur

Country Status (6)

Country Link
US (2) US6295299B1 (de)
EP (1) EP1016247B1 (de)
JP (1) JP4435974B2 (de)
AU (1) AU9211398A (de)
DE (1) DE69834823T2 (de)
WO (1) WO1999011036A1 (de)

Families Citing this family (91)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6665285B1 (en) * 1997-10-14 2003-12-16 Alvarion Israel (2003) Ltd. Ethernet switch in a terminal for a wireless metropolitan area network
US6590901B1 (en) * 1998-04-01 2003-07-08 Mosaid Technologies, Inc. Method and apparatus for providing a packet buffer random access memory
US7100020B1 (en) * 1998-05-08 2006-08-29 Freescale Semiconductor, Inc. Digital communications processor
JP3141850B2 (ja) * 1998-07-10 2001-03-07 日本電気株式会社 時分割スイッチング装置および時分割スイッチング方法、並びに記録媒体
US6266705B1 (en) * 1998-09-29 2001-07-24 Cisco Systems, Inc. Look up mechanism and associated hash table for a network switch
US6226332B1 (en) * 1998-11-13 2001-05-01 Broadcom Corporation Multi-pair transceiver decoder system with low computation slicer
US7031324B1 (en) * 1999-03-22 2006-04-18 Cisco Technology, Inc. Local area network/wide area network switch
US6567379B1 (en) * 1999-06-09 2003-05-20 Cisco Technology, Inc. Traffic monitor using leaky bucket with variable fill
US6697873B1 (en) * 1999-12-20 2004-02-24 Zarlink Semiconductor V.N., Inc. High speed MAC address search engine
US6757742B1 (en) * 2000-05-25 2004-06-29 Advanced Micro Devices, Inc. Computer-based system for validating hash-based table lookup schemes in a network switch
EP1162797B1 (de) * 2000-06-09 2010-12-08 Broadcom Corporation Flexibler Protokoll-header für Netzwerk-switch
US7725558B2 (en) * 2000-07-26 2010-05-25 David Dickenson Distributive access controller
US7373425B2 (en) * 2000-08-22 2008-05-13 Conexant Systems, Inc. High-speed MAC address search engine
JP3897994B2 (ja) * 2001-05-31 2007-03-28 富士通株式会社 スイッチ装置およびデータ転送システム
US7151774B1 (en) * 2001-06-13 2006-12-19 Advanced Micro Devices, Inc. Method and apparatus for trunking links having different transmission rates
US7142557B2 (en) * 2001-12-03 2006-11-28 Xilinx, Inc. Programmable logic device for wireless local area network
US7362751B2 (en) * 2001-10-03 2008-04-22 Topside Research, Llc Variable length switch fabric
US6914901B1 (en) * 2001-12-05 2005-07-05 Cisco Technology, Inc. System and method for communicating using multiple memory banks
US7584262B1 (en) 2002-02-11 2009-09-01 Extreme Networks Method of and system for allocating resources to resource requests based on application of persistence policies
US7814204B1 (en) 2002-02-11 2010-10-12 Extreme Networks, Inc. Method of and system for analyzing the content of resource requests
US7447777B1 (en) 2002-02-11 2008-11-04 Extreme Networks Switching system
US7000052B2 (en) * 2003-02-24 2006-02-14 Cisco Technology, Inc. System and method for configuring and deploying input/output cards in a communications environment
US7571287B2 (en) * 2003-03-13 2009-08-04 Marvell World Trade Ltd. Multiport memory architecture, devices and systems including the same, and methods of using the same
US7272672B1 (en) 2003-04-01 2007-09-18 Extreme Networks, Inc. High speed bus with flow control and extended burst enhancements between sender and receiver wherein counter is maintained at sender for free buffer space available
US7366935B1 (en) 2003-04-01 2008-04-29 Extreme Networks, Inc. High speed bus with alignment, re-timing and buffer underflow/overflow detection enhancements
US8861515B2 (en) 2003-04-22 2014-10-14 Agere Systems Llc Method and apparatus for shared multi-bank memory in a packet switching system
US20050021658A1 (en) * 2003-05-09 2005-01-27 Nicholas Charles Kenneth Network switch with shared memory
US7590124B2 (en) * 2003-09-30 2009-09-15 Intel Corporation Encapsulation technique
US8250295B2 (en) 2004-01-05 2012-08-21 Smart Modular Technologies, Inc. Multi-rank memory module that emulates a memory module having a different number of ranks
US7916574B1 (en) 2004-03-05 2011-03-29 Netlist, Inc. Circuit providing load isolation and memory domain translation for memory module
US7289386B2 (en) 2004-03-05 2007-10-30 Netlist, Inc. Memory module decoder
US7453874B1 (en) 2004-03-30 2008-11-18 Extreme Networks, Inc. Method and system for incrementally updating a checksum in a network data packet
US7463628B2 (en) * 2004-03-30 2008-12-09 Extreme Networks, Inc. Packet data modification processor command instruction set
US8161270B1 (en) 2004-03-30 2012-04-17 Extreme Networks, Inc. Packet data modification processor
US7385984B2 (en) * 2004-03-30 2008-06-10 Extreme Networks, Inc. Packet processing system architecture and method
US7606263B1 (en) 2004-03-30 2009-10-20 Extreme Networks, Inc. Packet parser
US7613209B1 (en) 2004-03-30 2009-11-03 Extreme Networks, Inc. System and method for egress packet marking
US7292591B2 (en) * 2004-03-30 2007-11-06 Extreme Networks, Inc. Packet processing system architecture and method
US7649879B2 (en) * 2004-03-30 2010-01-19 Extreme Networks, Inc. Pipelined packet processor
US7822032B1 (en) 2004-03-30 2010-10-26 Extreme Networks, Inc. Data structures for supporting packet data modification operations
US7539750B1 (en) 2004-03-30 2009-05-26 Extreme Networks, Inc. System and method for packet processor status monitoring
US7304996B1 (en) 2004-03-30 2007-12-04 Extreme Networks, Inc. System and method for assembling a data packet
US7889750B1 (en) 2004-04-28 2011-02-15 Extreme Networks, Inc. Method of extending default fixed number of processing cycles in pipelined packet processor architecture
US8464093B1 (en) 2004-09-03 2013-06-11 Extreme Networks, Inc. Memory array error correction
WO2006042155A2 (en) * 2004-10-08 2006-04-20 E-Klone, Inc. Floating vector scrambling methods and apparatus
US7606249B1 (en) 2004-12-21 2009-10-20 Extreme Networks, Inc. Methods and systems for caching packets to be written to or read from packet memory
US8560795B2 (en) * 2005-06-30 2013-10-15 Imec Memory arrangement for multi-processor systems including a memory queue
US7843927B1 (en) 2006-12-22 2010-11-30 Extreme Networks, Inc. Methods, systems, and computer program products for routing packets at a multi-mode layer 3 packet forwarding device
US7894451B2 (en) * 2005-12-30 2011-02-22 Extreme Networks, Inc. Method of providing virtual router functionality
US7817633B1 (en) 2005-12-30 2010-10-19 Extreme Networks, Inc. Method of providing virtual router functionality through abstracted virtual identifiers
US7822033B1 (en) * 2005-12-30 2010-10-26 Extreme Networks, Inc. MAC address detection device for virtual routers
US7802296B2 (en) * 2006-08-23 2010-09-21 Cisco Technology, Inc. Method and system for identifying and processing secure data frames
US8004961B1 (en) * 2006-09-28 2011-08-23 National Semiconductor Corporation Independently configurable port redirection in a multi-port ethernet physical layer
US8234425B1 (en) 2007-06-27 2012-07-31 Marvell International Ltd. Arbiter module
US7949817B1 (en) 2007-07-31 2011-05-24 Marvell International Ltd. Adaptive bus profiler
US9083609B2 (en) 2007-09-26 2015-07-14 Nicira, Inc. Network operating system for managing and securing networks
US8131915B1 (en) 2008-04-11 2012-03-06 Marvell Intentional Ltd. Modifying or overwriting data stored in flash memory
US8516185B2 (en) 2009-07-16 2013-08-20 Netlist, Inc. System and method utilizing distributed byte-wise buffers on a memory module
US8154901B1 (en) * 2008-04-14 2012-04-10 Netlist, Inc. Circuit providing load isolation and noise reduction
US8787060B2 (en) 2010-11-03 2014-07-22 Netlist, Inc. Method and apparatus for optimizing driver load in a memory package
US8683085B1 (en) 2008-05-06 2014-03-25 Marvell International Ltd. USB interface configurable for host or device mode
US8423710B1 (en) 2009-03-23 2013-04-16 Marvell International Ltd. Sequential writes to flash memory
WO2010115060A2 (en) 2009-04-01 2010-10-07 Nicira Networks Method and apparatus for implementing and managing virtual switches
US8213236B1 (en) 2009-04-21 2012-07-03 Marvell International Ltd. Flash memory
US9128632B2 (en) 2009-07-16 2015-09-08 Netlist, Inc. Memory module with distributed data buffers and method of operation
US20110216769A1 (en) * 2010-03-08 2011-09-08 Brocade Communications Systems, Inc. Dynamic Path Selection
US8688922B1 (en) * 2010-03-11 2014-04-01 Marvell International Ltd Hardware-supported memory management
US8331373B2 (en) 2010-03-15 2012-12-11 Extreme Networks, Inc. Methods, systems, and computer readable media for automatically selecting between internet protocol switching modes on a per-module basis in a packet forwarding device
US10103939B2 (en) 2010-07-06 2018-10-16 Nicira, Inc. Network control apparatus and method for populating logical datapath sets
US9525647B2 (en) 2010-07-06 2016-12-20 Nicira, Inc. Network control apparatus and method for creating and modifying logical switching elements
US8817621B2 (en) 2010-07-06 2014-08-26 Nicira, Inc. Network virtualization apparatus
US9680750B2 (en) 2010-07-06 2017-06-13 Nicira, Inc. Use of tunnels to hide network addresses
US8964528B2 (en) 2010-07-06 2015-02-24 Nicira, Inc. Method and apparatus for robust packet distribution among hierarchical managed switching elements
US8756394B1 (en) 2010-07-07 2014-06-17 Marvell International Ltd. Multi-dimension memory timing tuner
US8605732B2 (en) 2011-02-15 2013-12-10 Extreme Networks, Inc. Method of providing virtual router functionality
US9043452B2 (en) 2011-05-04 2015-05-26 Nicira, Inc. Network control apparatus and method for port isolation
CN106850878B (zh) 2011-08-17 2020-07-14 Nicira股份有限公司 逻辑l3路由
US9288081B2 (en) 2011-08-17 2016-03-15 Nicira, Inc. Connecting unmanaged segmented networks by managing interconnection switching elements
US8913611B2 (en) 2011-11-15 2014-12-16 Nicira, Inc. Connection identifier assignment and source network address translation
JP5833246B2 (ja) * 2011-10-25 2015-12-16 ニシラ， インコーポレイテッド ユニバーサルフローを変換するためのシャーシコントローラ
US9178833B2 (en) 2011-10-25 2015-11-03 Nicira, Inc. Chassis controller
AU2013249154B2 (en) 2012-04-18 2015-12-10 Nicira, Inc. Exchange of network state information between forwarding elements
CN102833591B (zh) * 2012-08-09 2015-08-12 中兴通讯股份有限公司 交互式网络电视系统中点播服务不中断的方法及装置
US9923760B2 (en) 2015-04-06 2018-03-20 Nicira, Inc. Reduction of churn in a network control system
US10204122B2 (en) 2015-09-30 2019-02-12 Nicira, Inc. Implementing an interface between tuple and message-driven control entities
CN106776405A (zh) * 2015-11-20 2017-05-31 英业达科技有限公司 输入/输出端口切换方法及其电子装置及系统
US11019167B2 (en) 2016-04-29 2021-05-25 Nicira, Inc. Management of update queues for network controller
CN107256363B (zh) * 2017-06-13 2020-03-06 杭州华澜微电子股份有限公司 一种由加解密模块阵列组成的高速加解密装置
WO2021146964A1 (zh) * 2020-01-21 2021-07-29 华为技术有限公司 一种交换网芯片及交换设备
US11599649B2 (en) * 2020-06-29 2023-03-07 Rockwell Automation Technologies, Inc. Method and apparatus for managing transmission of secure data packets
US11606346B2 (en) 2020-06-29 2023-03-14 Rockwell Automation Technologies, Inc. Method and apparatus for managing reception of secure data packets

Family Cites Families (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4698802A (en) * 1986-03-07 1987-10-06 American Telephone And Telegraph Company And At&T Information Systems Inc. Combined circuit and packet switching system
US5365519A (en) * 1991-03-05 1994-11-15 Hitachi, Ltd. ATM switch1ng system connectable to I/O links having different transmission rates
DE3878647D1 (de) * 1987-11-11 1993-04-01 Siemens Ag Vermittlungsknoten fuer die vermittlung von in datenpaketen uebertragenen datensignalen.
JPH01177239A (ja) * 1988-01-06 1989-07-13 Nec Corp パケット集線装置及びパケット交換機
CA2015514C (en) * 1989-08-22 1996-08-06 Mitsuru Tsuboi Packet switching system having bus matrix switch
US5475680A (en) * 1989-09-15 1995-12-12 Gpt Limited Asynchronous time division multiplex switching system
JPH03220836A (ja) * 1990-01-25 1991-09-30 Nec Corp 非同期伝送モード交換装置
JPH07112181B2 (ja) * 1991-04-18 1995-11-29 松下電器産業株式会社 データ多重化回路
US5313624A (en) * 1991-05-14 1994-05-17 Next Computer, Inc. DRAM multiplexer
FI88840C (fi) * 1991-10-18 1993-07-12 Nokia Oy Ab Foerfarande foer att utfoera en koppling i ett pao centralminne baserat kopplingsfaelt samt kopplingsfaelt
EP0544964B1 (de) * 1991-11-29 1997-02-19 International Business Machines Corporation Vorrichtung zur Speicherung und Durchschaltung und Verfahren zur Datensicherung während der Speicherung
US5742760A (en) * 1992-05-12 1998-04-21 Compaq Computer Corporation Network packet switch using shared memory for repeating and bridging packets at media rate
JP2655481B2 (ja) * 1994-04-28 1997-09-17 日本電気株式会社 出力バッファ型ａｔｍスイッチにおける優先制御方法
US5412646A (en) * 1994-05-13 1995-05-02 At&T Corp. Asynchronous transfer mode switch architecture
US5475679A (en) * 1994-12-08 1995-12-12 Northern Telecom Limited Large capacity ATM switch
JP2856104B2 (ja) * 1995-04-18 1999-02-10 日本電気株式会社 Ａｔｍスイッチ
US5774543A (en) * 1995-11-13 1998-06-30 Flowers; Calvin Telephone jack security device
US5724358A (en) * 1996-02-23 1998-03-03 Zeitnet, Inc. High speed packet-switched digital switch and method
US5781549A (en) * 1996-02-23 1998-07-14 Allied Telesyn International Corp. Method and apparatus for switching data packets in a data network
US5790545A (en) * 1996-03-14 1998-08-04 Motorola Inc. Efficient output-request packet switch and method

Also Published As

Publication number Publication date
EP1016247B1 (de) 2006-06-07
DE69834823T2 (de) 2006-12-21
AU9211398A (en) 1999-03-16
US6295299B1 (en) 2001-09-25
EP1016247A4 (de) 2000-10-04
US20020034189A1 (en) 2002-03-21
US7130308B2 (en) 2006-10-31
JP2001514464A (ja) 2001-09-11
JP4435974B2 (ja) 2010-03-24
WO1999011036A1 (en) 1999-03-04
EP1016247A1 (de) 2000-07-05

Similar Documents

Publication Publication Date Title
DE69834823D1 (de) Paketvermittlungsvorrichtung und -verfahren mit zentraler Speicherarchitektur
DK0796846T3 (da) 2-Aryl-substituerede pyridiner
KR970703078A (ko) Atm 아키텍쳐 및 스위칭 소자
FI102426B1 (fi) Menetelmä muistin toteuttamiseksi
DE69841090D1 (de) Ladungsregelungsverfahren und -vorrichtung
FI102424B1 (fi) Menetelmä muistin toteuttamiseksi
DE69803833T2 (de) Zeitwiedergabevorrichtung
DE69525666T2 (de) Selektivruf
DE69612975D1 (de) Schalteinrichtung
FI102425B1 (fi) Menetelmä muistin toteuttamiseksi
KR970004627A (ko) 모드 자동전환장치 및 방법
DE69837638D1 (de) Schweissverfahren und -vorrichtung
DE69815390D1 (de) Neuronale netzwerke
DE69430828T2 (de) Paketvermittlungssystem
DE69615646T2 (de) Selektivrufempfänger
DE69833623D1 (de) Druckvorrichtung und -verfahren
DE69515102D1 (de) Kernfunktionalisierte Sternblockcopolymere
FI963455A0 (fi) Datasiirtomenetelmä ja -laitteisto
DE69621534D1 (de) Selektivrufempfänger
DE69521029T2 (de) Vermittlungsvorrichtung
DE69626679D1 (de) Vermittlungseinrichtung
DE29619891U1 (de) Siebrechen
DE29516541U1 (de) Schal
FI960382A0 (fi) Menetelmä pakettimuotoisen yhteyden toteuttamiseksMenetelmä pakettimuotoisen yhteyden toteuttamiseksi i
KR970050674U (ko) 목도리

Legal Events

Date Code Title Description
8364 No opposition during term of opposition