WO2004023732A1 - Procede et appareil pour memoriser un identificateur de port dans un commutateur lan - Google Patents

Procede et appareil pour memoriser un identificateur de port dans un commutateur lan Download PDF

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Publication number
WO2004023732A1
WO2004023732A1 PCT/SG2002/000212 SG0200212W WO2004023732A1 WO 2004023732 A1 WO2004023732 A1 WO 2004023732A1 SG 0200212 W SG0200212 W SG 0200212W WO 2004023732 A1 WO2004023732 A1 WO 2004023732A1
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WO
WIPO (PCT)
Prior art keywords
hashing
vlan
address
value
mac address
Prior art date
Application number
PCT/SG2002/000212
Other languages
English (en)
Inventor
Shridhar Mubaraq Mishra
Guruprasad Ardhanari
Original Assignee
Infineon Technologies Ag
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 Infineon Technologies Ag filed Critical Infineon Technologies Ag
Priority to AU2002334573A priority Critical patent/AU2002334573A1/en
Priority to PCT/SG2002/000212 priority patent/WO2004023732A1/fr
Publication of WO2004023732A1 publication Critical patent/WO2004023732A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/46—Interconnection of networks
    • H04L12/4641—Virtual LANs, VLANs, e.g. virtual private networks [VPN]
    • 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]
    • 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

Definitions

  • the present invention relates to a scheme for VLAN learning in a switch such as an Ethernet.
  • Fig. 1 shows a physical LAN (local area network) including a switch 5 having a number of ports through which it is connected to a number of devices 7.
  • the switch 5 and devices 7 form a physical LAN (local area network).
  • Packets passing within the LAN include a destination address (DA) which is the MAC address of the device 7 to which the packet is directed, and a source address (SA) which is MAC address of the device 7 which sent the packet.
  • DA destination address
  • SA source address
  • the switch 5 is unaware of which devices are connected to its various ports, and a learning scheme is implemented in which, when then switch receives a first packet, it uses the SA and the knowledge of which port the packet arrived at to infer the MAC address associated with that port.
  • the learning by the switch is usually implemented as a hash table with 2/4 buckets and support for 4096/8192 addresses.
  • An egress port associated with a given MAC address is learnt by inserting an ID of that egress port into an address of the table which is Hash(MAC address), where hash is a hash function.
  • Hash MAC address
  • hash a hash function
  • VLANs ease network management, cut down on unnecessary traffic, and enhance LAN security.
  • This distinction is to be implemented by the switch 5, and thus is reconfigurable by alteration of the data within the memory of the switch rather than requiring physical reconnection of cables.
  • Packets in this scheme are associated with a VLAN ID in addition to their SA and DA, indicating the VLAN of the SA.
  • the VLAN may be part of the received packet, if the devices know which VLAN they are part of and so can insert it into packets they send.
  • the switch knows the correspondence of the MAC addresses with VLANs, the switch can use the SA MAC address (or any other field) to find the corresponding VLAN ID.
  • the switch 5 should support three forms of learning:
  • IDL Independent VLAN learning
  • a packet with a SA MAC address M1 and VLAN address V1 is received, it is learned in a table associated with V1 and placed in that table at an address derived by hashing M1. If later a packet is received with DA M1 but VLAN ID V2, the lookup will be done in the table associated with V2 and the address will not be found: the packet is not delivered.
  • V1 and V2 are grouped together and given a filtering identifier (FID).
  • FID filtering identifier
  • a later arriving packet with a DA of M1 and a VLAN ID of V2 will be able to find this packet since V2 is converted to F1 and the lookup based on F1 and hashed M1 finds the stored data, but a later arriving packet with a VLAN ID V3 will not find M1 in the look-up table.
  • the present invention relates aims to provide a new scheme for VLAN learning.
  • the present invention proposes that a single memory is used to store MAC addresses of multiple VLANs.
  • the hashing algorithm which generates the address within the memory at which port is learnt uses a hashing algorithm which is a function both of the MAC address and of a second hashing value determined by the VLAN ID.
  • a hashing algorithm which is a function both of the MAC address and of a second hashing value determined by the VLAN ID.
  • the hashing algorithm finds the look-up address using the MAC address and a second hashing value determined by the VLAN value of the second packet. Thus, the stored port will only be found if the second hashing values of the two packets are the same.
  • Figure 1 shows a known physical local area network
  • Figure 2 shows the steps of a learning or lookup process in an embodiment of the invention
  • Fig. 3 is a more detailed form of Fig. 2 in one mode
  • Figure 4 shows the steps of entering data into a memory based on the hashed address.
  • the algorithm takes as input the VLAN of a packet and the SA (in the case of learning) or the DA (in the case of a lookup).
  • a first step the VLAN ID of the packet is input to a conversion table to obtain a second hashing value.
  • step 2 the SA or DA is input together with the second hashing value to a hashing algorithm which performs a hashing function of both of them to generate an address.
  • step 3 the address obtained is used as an address at which data is inserted into (in the case of learning) or extracted from (in the case of lookup) a memory.
  • the conversion table used in step 2 is different in the case of IVL (in which the second hashing value is different for all VLANs), in the case of SVL (in which the second hashing value is the same for all VLANs), and in the case of combination VLAN (in which the second hashing value is the same for all VLANs having the same FID.
  • FIG. 3 is a more detailed version of steps 1 and 2 of Fig. 2 in the case of combination VLAN.
  • Step 1 of Fig. 2 is broken into two substeps 1a and 1b.
  • the VLAN ID (12-bits long, to permit 4k VLANs as defined by IEEE standard 802.3D), is converted to a VID in a step 1a.
  • the VID may be 10 bits depending on the number of VLANs supported.
  • step 1 b the VID is converted to a 10 bit FID.
  • Step 2 is performed in by constructing a string 9 incorporating the FID and the MAC address, and then hashing it by a hash function 13 to form an address 14 of fer example 11 bits (the length may depend upon the size of the MAC address table). Note that in the case of independent VLAN learning step 1 b is omitted.
  • Fig. 4 shows how the 11-bit output of the hash function 13 of Fig. 3 is used as an address 14 in a MAC table 15 with 2k entries. Each entry is has 4 buckets (i.e. locations for associations of MAC addresses and ports). Different values of (MAC address, second hashing value) which happen to map to the same address are stored in different ones of these buckets.
  • the invention is preferably implemented in the switch 5 of a physical layer network shown in Fig. 1 , such as an Ethernet switch.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Computer Security & Cryptography (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)
  • Small-Scale Networks (AREA)

Abstract

Selon l'invention, un système d'apprentissage destiné à être utilisé dans un commutateur Ethernet apprend des adresses MAC associées à des ports. Les adresses MAC correspondent à des dispositifs dans différents VLAN. Un paquet, reçu au niveau d'un port donné, est analysé pour permettre de trouver l'adresse source (SA) et la valeur de l'identificateur de VLAN (VLAN ID). Cette valeur est utilisée pour permettre de trouver une deuxième valeur de hachage (étape 1). Ensuite un algorithme de hachage (étape 2) génère une adresse dans la mémoire, adresse à laquelle l'apprentissage du port doit être effectué (à l'étape 3) au moyen d'un algorithme de hachage qui est fonction de l'adresse MAC et de la deuxième valeur de hachage. Lors de la réception ultérieure d'un deuxième paquet présentant une adresse de destination (DA) identique à l'adresse MAC, l'algorithme de hachage (étape 2) trouve l'adresse de consultation à laquelle une consultation est effectuée (à l'étape 3) au moyen de l'adresse MAC et d'une deuxième valeur de hachage déterminée (à l'étape 1) par la valeur VLAN du deuxième paquet.
PCT/SG2002/000212 2002-09-06 2002-09-06 Procede et appareil pour memoriser un identificateur de port dans un commutateur lan WO2004023732A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU2002334573A AU2002334573A1 (en) 2002-09-06 2002-09-06 Method and apparatus for storing a port identifier in a lan switch
PCT/SG2002/000212 WO2004023732A1 (fr) 2002-09-06 2002-09-06 Procede et appareil pour memoriser un identificateur de port dans un commutateur lan

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/SG2002/000212 WO2004023732A1 (fr) 2002-09-06 2002-09-06 Procede et appareil pour memoriser un identificateur de port dans un commutateur lan

Publications (1)

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WO2004023732A1 true WO2004023732A1 (fr) 2004-03-18

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PCT/SG2002/000212 WO2004023732A1 (fr) 2002-09-06 2002-09-06 Procede et appareil pour memoriser un identificateur de port dans un commutateur lan

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AU (1) AU2002334573A1 (fr)
WO (1) WO2004023732A1 (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006106588A1 (fr) * 2005-03-31 2006-10-12 Fujitsu Limited Dispositif de transfert de trames
WO2007041942A1 (fr) * 2005-10-09 2007-04-19 Huawei Technologies Co., Ltd. Système pour ethernet de support de la transmission de la multidiffusion spécifique à une source et procédé idoine
EP1863234A1 (fr) 2006-06-01 2007-12-05 Fujitsu Limited Système et procédé de gestion des ressources de table de routage dans un environnement commuté
CN100435528C (zh) * 2005-08-29 2008-11-19 杭州华三通信技术有限公司 减少网络内媒体接入控制地址学习的方法
CN100438439C (zh) * 2006-05-19 2008-11-26 华为技术有限公司 一种防止mac地址欺骗的方法
US7620043B2 (en) * 2005-09-29 2009-11-17 Fujitsu Limited Using CRC-15 as hash function for MAC bridge filter design
US7742408B2 (en) 2006-08-04 2010-06-22 Fujitsu Limited System and method for filtering packets in a switching environment
US7826468B2 (en) 2006-08-04 2010-11-02 Fujitsu Limited System and method for bypassing an output queue structure of a switch
WO2012087217A1 (fr) 2010-12-22 2012-06-28 Telefonaktiebolaget Lm Ericsson (Publ) Procédé et agencement de transfert de paquets de données
WO2012130157A1 (fr) * 2011-03-30 2012-10-04 华为技术有限公司 Procédé, dispositif côté réseau et système pour l'apprentissage d'une adresse de contrôle d'accès au support
EP3267637A1 (fr) * 2006-11-13 2018-01-10 Orckit Ip, Llc Multi-hébergement à base de hachage

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US5852607A (en) * 1997-02-26 1998-12-22 Cisco Technology, Inc. Addressing mechanism for multiple look-up tables
US5914938A (en) * 1996-11-19 1999-06-22 Bay Networks, Inc. MAC address table search unit
US6266705B1 (en) * 1998-09-29 2001-07-24 Cisco Systems, Inc. Look up mechanism and associated hash table for a network switch
WO2002019638A2 (fr) * 2000-08-31 2002-03-07 Mosaid Technologies Incorporated Procede et appareil de recherche dans une base de donnees de filtrage par une seule operation de recherche
US6356551B1 (en) * 1997-02-14 2002-03-12 Advanced Micro Devices, Inc. Method and network switch having dual forwarding models with a virtual lan overlay

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5914938A (en) * 1996-11-19 1999-06-22 Bay Networks, Inc. MAC address table search unit
US6356551B1 (en) * 1997-02-14 2002-03-12 Advanced Micro Devices, Inc. Method and network switch having dual forwarding models with a virtual lan overlay
US5852607A (en) * 1997-02-26 1998-12-22 Cisco Technology, Inc. Addressing mechanism for multiple look-up tables
US6266705B1 (en) * 1998-09-29 2001-07-24 Cisco Systems, Inc. Look up mechanism and associated hash table for a network switch
WO2002019638A2 (fr) * 2000-08-31 2002-03-07 Mosaid Technologies Incorporated Procede et appareil de recherche dans une base de donnees de filtrage par une seule operation de recherche

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006106588A1 (fr) * 2005-03-31 2006-10-12 Fujitsu Limited Dispositif de transfert de trames
US7724736B2 (en) 2005-03-31 2010-05-25 Fujitsu Limited Frame forwarding apparatus
CN100435528C (zh) * 2005-08-29 2008-11-19 杭州华三通信技术有限公司 减少网络内媒体接入控制地址学习的方法
US7620043B2 (en) * 2005-09-29 2009-11-17 Fujitsu Limited Using CRC-15 as hash function for MAC bridge filter design
WO2007041942A1 (fr) * 2005-10-09 2007-04-19 Huawei Technologies Co., Ltd. Système pour ethernet de support de la transmission de la multidiffusion spécifique à une source et procédé idoine
CN100438439C (zh) * 2006-05-19 2008-11-26 华为技术有限公司 一种防止mac地址欺骗的方法
EP1863234A1 (fr) 2006-06-01 2007-12-05 Fujitsu Limited Système et procédé de gestion des ressources de table de routage dans un environnement commuté
US7742408B2 (en) 2006-08-04 2010-06-22 Fujitsu Limited System and method for filtering packets in a switching environment
US7826468B2 (en) 2006-08-04 2010-11-02 Fujitsu Limited System and method for bypassing an output queue structure of a switch
EP3267637A1 (fr) * 2006-11-13 2018-01-10 Orckit Ip, Llc Multi-hébergement à base de hachage
WO2012087217A1 (fr) 2010-12-22 2012-06-28 Telefonaktiebolaget Lm Ericsson (Publ) Procédé et agencement de transfert de paquets de données
EP2656553A1 (fr) * 2010-12-22 2013-10-30 Telefonaktiebolaget LM Ericsson (PUBL) Procédé et agencement de transfert de paquets de données
EP2656553A4 (fr) * 2010-12-22 2016-06-01 Ericsson Telefon Ab L M Procédé et agencement de transfert de paquets de données
WO2012130157A1 (fr) * 2011-03-30 2012-10-04 华为技术有限公司 Procédé, dispositif côté réseau et système pour l'apprentissage d'une adresse de contrôle d'accès au support
US9294399B2 (en) 2011-03-30 2016-03-22 Huawei Technologies Co., Ltd. Method for learning media access control address, network device, and system

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