Alta Disponibilidade - Fibre Channel
Padrão Fibre Channel
O padrão Fibre Channel foi definido pelo ANSI em 1994, como uma interface de transferência de dados, visando oferecer uma alternativa para substituição das interfaces de armazenamento existentes. Seu objetivo era simplificar o sistema HIPPI - HIgh Performance Parallel Interface (que tinha as desvantagens de usar 50 pares de cabos, conectores enormes e um limite pequeno de distâncias permitidas). Os protocolos Fibre Channel apareceram para simplificar as ligações e diminuir as perdas de sinal, aumentando assim as distâncias máximas permitidas. Mais tarde tentou ligar discos SCSI, aumentar a velocidade e o numero de dispositivos permitidos. Também adicionou suporte para protocolos de várias camadas de "alto-nível", incluindo SCSI, ATM e IP, sendo o SCSI o mais usado.
O padrão Fibre Channel foi definido pelo ANSI em 1994, como uma interface de transferência de dados, visando oferecer uma alternativa para substituição das interfaces de armazenamento existentes. Seu objetivo era simplificar o sistema HIPPI - HIgh Performance Parallel Interface (que tinha as desvantagens de usar 50 pares de cabos, conectores enormes e um limite pequeno de distâncias permitidas). Os protocolos Fibre Channel apareceram para simplificar as ligações e diminuir as perdas de sinal, aumentando assim as distâncias máximas permitidas. Mais tarde tentou ligar discos SCSI, aumentar a velocidade e o numero de dispositivos permitidos. Também adicionou suporte para protocolos de várias camadas de "alto-nível", incluindo SCSI, ATM e IP, sendo o SCSI o mais usado.
Os discos Fibre Channel são o irmão mais novo dos discos SCSI. Estes discos são definidos como parte dos discos SCSI-3. Permite maiores velocidades e um maior numero de discos. O nome deve a sua origem ao facto de estes discos serem criados originalmente para operar com canais de fibra óptica. Embora também possa trabalhar com cablagem de cobre.
O padrão foi projetado para endereçar um meio comum de interligação para os três tipos diferentes de tráfego de uma rede de comunicação: voz, dados e imagem. Suporta diversos protocolos de transporte, incluindo IP e SCSI, permitindo a utilização de cabeamento metálico ou óptico na interface física, o que torna essa tecnologia única para atender às necessidades de armazenamento de dados e de comunicação em redes de computadores.
Armazenamento
Com relação ao armazenamento de informações, o surgimento de plataformas que empregam componentes de rede com base no Fibre Channel, tais como hubs e switches, passaram a oferecer maiores facilidades na forma de gerenciar a informação, protegendo e compartilhando volumes crescentes de aplicações de missão crítica. Assim, as características do padrão Fibre Channel (confiabilidade, performance e conectividade) permitem que diferentes topologias de redes possam ser aplicadas no ambiente de armazenamento de dados.
A tecnologia Fibre Channel é projetada para combinar as características de simplicidade e rapidez dos canais de I/O com a flexibilidade e interconectividade das redes de comunicação baseadas em protocolos. Oferece um sistema de comunicação eficiente para uma grande variedade de dispositivos e aplicações, por meio de uma única interface de comunicação.
Armazenamento
Com relação ao armazenamento de informações, o surgimento de plataformas que empregam componentes de rede com base no Fibre Channel, tais como hubs e switches, passaram a oferecer maiores facilidades na forma de gerenciar a informação, protegendo e compartilhando volumes crescentes de aplicações de missão crítica. Assim, as características do padrão Fibre Channel (confiabilidade, performance e conectividade) permitem que diferentes topologias de redes possam ser aplicadas no ambiente de armazenamento de dados.
A tecnologia Fibre Channel é projetada para combinar as características de simplicidade e rapidez dos canais de I/O com a flexibilidade e interconectividade das redes de comunicação baseadas em protocolos. Oferece um sistema de comunicação eficiente para uma grande variedade de dispositivos e aplicações, por meio de uma única interface de comunicação.
FC é um conjunto de protocolos.
As implementações actualmente usadas destes protocolos é o
1) Fibre Channel Arbitrated Loop (FC-AL)
2) Switched Fabric (FC-SW).
Topologias
O padrão permite a conexão de dispositivos nos modos Point-to-Point, Arbitrated Loop e Fabric Switching:
1) Point-to-Point (FC-P2P): Dois dispositivos ligados diretamente. Esta é a topologia mais simples. É a topologia de nível básico do Fibre Channel, sendo utilizada quando há necessidade de alta performance no armazenamento de dados para um host. Nesta topologia, uma unidade de disco ou um conjunto de discos é ligado ao host e toda a banda disponível fica dedicada a ele;
2) Arbitrated Loop (FC-AL): Nesta topologia todos os dispositivos estão ligados em loop ou anel. Adicionar ou remover dispositivos obriga a ser interrompida toda a atividade. A falha num dispositivo quebra o anel. Existem Hubs Fibre Channel que permitim ligações múltiplas entre dispositivos. Trata-se de uma topologia de nível intermediário, que permite ligar até 126 dispositivos de rede em anel. As portas em um Arbitrated Loop devem possuir as funções da porta tipo N e tipo F, denominadas de portas NL. O controle de acesso ao meio desta topologia funciona de maneira bem semelhante à rede Token Ring;
3) Switched Fabric (FC-SW): Todos os dispositivos FC estão ligados a switches (Fabric), numa ligação similar às redes Ethernet atuais. Quando existe um Fabric a fibra pode ser ligada uma porta node (N_Port) e a uma porta do Fabric (F_Port). É uma topologia de nível avançado e permite a conexão de um número ilimitado de dispositivos, oferecendo uma banda completa para cada conexão por meio de um switch usado para interconectar um certo número de portas do tipo N. A figura 7(a) ilustra esta topologia, que pode também ser composta por uma rede de comutação fabric. Uma topologia combinada de arbitrated loop com fabric switching pode ser utilizada para otimizar o custo da configuração. Neste caso, um dos nós do arbitrated loop deve ser um nó fabric-loop, que possui uma porta do tipo FL.
Figura 2 - Tipos de portas Fibre Channel
Arquitetura de Protocolos
O padrão Fibre Channel é organizado em cinco níveis, conforme ilustrado na figura seguinte:
Figura 4 - Protocolos Fibre Channel
Os níveis de FC-0 a FC-2 definem a camada física e a sinalização (FC-PH). Ainda não existe padronização para o nível FC-3. No nível FC-4, padrões proprietários têm sido desenvolvidos para suportar uma variedade de canais e redes existentes.
Camada Física
Uma das grandes vantagens do padrão Fibre Channel é o suporte a uma variedade de opções para o meio físico, para a taxa de transmissão neste meio físico e a topologia da rede. O padrão para o nível FC-0 inclui uma notação para definir um meio de transmissão específico operando com uma taxa de transmissão específica. As duas implementações mais comuns são 100-TW-S-EL e 100-M5-I-SL.
Figura 5 - Nomenclatura FC-0 Confiabilidade, Performance e Conectividade
O Fibre Channel foi desenhado para permitir a conexão e desconexão de dispositivos, sem causar parada no funcionamento do barramento como um todo. Além disso, permite adotar uma configuração de anel duplo, formando um link de 100Mbps. Como utiliza a interface serial, os dados são transmitidos bit a bit, com uma taxa de transferência de pico de 106Mbps. A integridade dos dados durante o processo de transferência é verificada por meio de mecanismos de sincronismo e pela utilização de "checksum", verificado pelo receptor da informação. Se ocorrer alguma inconsistência, os dados são retransmitidos pelo emissor. A conectividade do Fibre Channel permite que as organizações possam consolidar dados entre servidores e sistemas de armazenamento bastante dispersos e ao mesmo tempo, dar suporte aos crescentes volumes de dados corporativos. Neste aspecto, o padrão oferece vários benefícios para os servidores e sistemas de armazenamento (as atuais implementações SCSI impõem uma limitação na distância em 25 metros entre os servidores e os sistemas de armazenamento de dados enquanto o FC permite uma distância de até 10Km entre os dispositivos da rede de "Enterprise Storage"), conectividade aberta e maiores taxas de transferência de dados. Uma única plataforma Fibre Channel pode lidar simultaneamente com conexões de canais paralelos e seriais de mainframes e com servidores de sistemas abertos.
Camadas Fibre Channel:
O FC é um protocolo por camadas. Consiste nas seguintes 5 camadas:
1) FC0 Camada física - inclui cabos, conectores, parametros opticos e eléctricos, etc;
2) FC1 Camada de ligação de dados - implementa a codificação e descodificação do sinal e controlo de erros;
3) FC2 Camada de rede - define a estrutura das frames do FC e os protocolos de sinal, de Flow Control e as as classes de serviço que o FC suporta. De forma a suportar estes serviços, o FC-2 define formatos de mensagens: Ordered Set, Frame, Sequence e Exchange;
4) FC3 Camada que implementa funções auxiliares; - Striping - Multiplica largura de banda usando multiplas N_ports; - Hunt groups - Habilidade de mais do que uma porta responder a um mesmo endereço (diminui as hipoteses de procurar N_port ocupadas); - Multicast - Uma transmissão para várias portas destino. (p.e. todas as N_Ports de um Fabric (broadcast) ou apenas para um subconjunto de N_Ports num Fabric)
5) FC4 Camada da aplicação - define interfaces com vários protocolos de nivel superior; responsável pelo encapsulamento das várias camadas;
FC0, FC1 e FC2 são tambem conhecidas por FC-PH - Camada Fisica do FC. Os productos Fibre Channel estão disponiveis a velocidades de 1 Gbit/s, 2 Gbit/s e 4 Gbit/s. Já existe o standard de 10 Gbit/s, mas não existem ainda productos que usem este standard. Está a ser desenvolvido um standard de 8 Gbit/s. Produtos baseados nos standard 1, 2, 4 e 8 Gbit/s deverão ser interoperaveis , mas o standard de 10 Gbit/s precisa de uma mudança ""radical"".
Características
O Fibre Channel possui as seguintes características:
1) Links de comunicação full-duplex com duas fibras ópticas por link (opções de outros meios);
2) Taxas de transmissão de 100Mbps a 3,2Gbps em um único link (200Mbps até 6,4Gbps em um link full-duplex);
3) Suporte para distâncias até 10km;
4) Suporte a múltiplos níveis de custo/performance, de pequenos sistemas a supercomputadores;
5) Suporte a comandos de interfaces de redes e canais de I/O existentes.
Figura 1 - Principais aplicações Fibre Channel
Terminologia
O Fibre Channel possui as seguintes características:
1) Links de comunicação full-duplex com duas fibras ópticas por link (opções de outros meios);
2) Taxas de transmissão de 100Mbps a 3,2Gbps em um único link (200Mbps até 6,4Gbps em um link full-duplex);
3) Suporte para distâncias até 10km;
4) Suporte a múltiplos níveis de custo/performance, de pequenos sistemas a supercomputadores;
5) Suporte a comandos de interfaces de redes e canais de I/O existentes.
Figura 1 - Principais aplicações Fibre ChannelTerminologia
O Fibre Channel faz uso de um conjunto de terminologia específica, sendo que os principais termos são:
a) Porta: uma porta de comunicação dentro de um nó que realiza a comunicação sobre um link Fibre Channel. A porta do tipo N é usada na topologia Point-to-Point, a porta L é usada na topologia Arbitrated Loop, a porta do tipo F é de acesso no Fabric Switch e uma porta FL é utilizada na interconexão das topologias Arbitrated Loop e Fabric Switching;
b) Fabric: conjunto de componentes que realizam a comutação de frames. Interconecta diversas portas do tipo N;
c) Nó: conjunto de portas do tipo N.
a) Porta: uma porta de comunicação dentro de um nó que realiza a comunicação sobre um link Fibre Channel. A porta do tipo N é usada na topologia Point-to-Point, a porta L é usada na topologia Arbitrated Loop, a porta do tipo F é de acesso no Fabric Switch e uma porta FL é utilizada na interconexão das topologias Arbitrated Loop e Fabric Switching;
b) Fabric: conjunto de componentes que realizam a comutação de frames. Interconecta diversas portas do tipo N;
c) Nó: conjunto de portas do tipo N.
O Fibre Channel parece mais com as tradicionais redes de comutação de pacotes do que com os meios compartilhados de uma LAN. Desta forma, o Fibre Channel não se preocupa com as questões de controle de acesso ao meio (MAC).
A figura seguinte mostra as distâncias máximas permitidas por tipo de meio físico utilizado no padrão Fibre Channel.
Figura 6 - Distâncias máximas para Fibre Channel
Características FCRPM : de 10.000 até 15.000 Buffer 8/16 MB Average Seek Time: 4.7 ms (Ultra Fast) 4 Gigabit/seg interface. Capacidades: 147GB / 73GB / 36 GB
ConclusãoOs discos Fibre Channel e SCSI são os mais rápidos e mais confiáveis para servidores, estações de trabalho e soluções RAID. O FC e SCSI são ideais para computadores multi utilizador, multi tarefa e multi processador, produção áudio e vídeo.
Figura 6 - Distâncias máximas para Fibre Channel
Características FCRPM : de 10.000 até 15.000 Buffer 8/16 MB Average Seek Time: 4.7 ms (Ultra Fast) 4 Gigabit/seg interface. Capacidades: 147GB / 73GB / 36 GB
ConclusãoOs discos Fibre Channel e SCSI são os mais rápidos e mais confiáveis para servidores, estações de trabalho e soluções RAID. O FC e SCSI são ideais para computadores multi utilizador, multi tarefa e multi processador, produção áudio e vídeo.
Glossário
Arbitrated Loop Topology - topologia Fibre Channel que suporta uma solução para ligar múltiplos dispositivos em anel
E_Port - porta de expansão num switch. Utilizada para ligar vários switchs a um Fibre Channel Fabric.
F_Port - porta de um Fabric onde pode ser ligado uma N_port ou NL_port FCP - Fibre Channel Protocolo
G_Port - porta genérica de um switch, que pode ser uma F_port ou E_port
L_Port - um porta de um dispositivo em loop (FC-AL)
N_Port - porta de um nó usando a topologia point-to-point
NL_Port - porta de um nó usada nas 3 topologias FC
Fibre Channel RFCsRFCs:
RFC 4044 - Fibre Channel Management MIB RFC 2837 - Definitions of Managed Objects for the Fabric Element in Fibre Channel Standard RFC 2625 - IP and ARP over Fibre Channel Drafts:
draft-ietf-imss-fc-rtm-mib-00.txt Fibre-Channel Routing Information MIB draft-ietf-imss-fc-fspf-mib-00.txt MIB for Fibre-Channel's Fabric Shortest Path First Protocol
RFC 4044 - Fibre Channel Management MIB RFC 2837 - Definitions of Managed Objects for the Fabric Element in Fibre Channel Standard RFC 2625 - IP and ARP over Fibre Channel Drafts:
draft-ietf-imss-fc-rtm-mib-00.txt Fibre-Channel Routing Information MIB draft-ietf-imss-fc-fspf-mib-00.txt MIB for Fibre-Channel's Fabric Shortest Path First Protocol
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Fibre Channel is a gigabit-speed network technology primarily used for storage networking. Fibre Channel is standardized in the T11 Technical Committee of the InterNational Committee for Information Technology Standards (INCITS), an American National Standards Institute (ANSI)–accredited standards committee. It started for use primarily in the supercomputer field, but has become the standard connection type for storage area networks (SAN) in enterprise storage. Despite common connotations of its name, Fibre Channel signaling can run on both twisted pair copper wire and fiber-optic cables.
Fibre Channel Protocol (FCP) is the interface protocol of SCSI on the Fibre Channel.
[edit] History
Fibre Channel started in 1988, with ANSI standard approval in 1994, as a way to simplify the HIPPI system then in use for similar roles. HIPPI used a massive 50-pair cable with bulky connectors, and had limited cable lengths. Fibre Channel was primarily concerned with simplifying the connections and increasing distances, as opposed to increasing speeds. Later, designers added the goals of connecting SCSI disk storage, providing higher speeds and far greater numbers of connected devices.
It also added support for any number of "upper layer" protocols, including SCSI, ATM, and IP, with SCSI being the predominant usage.
Fibre Channel Variants
Fibre Channel is a gigabit-speed network technology primarily used for storage networking. Fibre Channel is standardized in the T11 Technical Committee of the InterNational Committee for Information Technology Standards (INCITS), an American National Standards Institute (ANSI)–accredited standards committee. It started for use primarily in the supercomputer field, but has become the standard connection type for storage area networks (SAN) in enterprise storage. Despite common connotations of its name, Fibre Channel signaling can run on both twisted pair copper wire and fiber-optic cables.
Fibre Channel Protocol (FCP) is the interface protocol of SCSI on the Fibre Channel.
[edit] History
Fibre Channel started in 1988, with ANSI standard approval in 1994, as a way to simplify the HIPPI system then in use for similar roles. HIPPI used a massive 50-pair cable with bulky connectors, and had limited cable lengths. Fibre Channel was primarily concerned with simplifying the connections and increasing distances, as opposed to increasing speeds. Later, designers added the goals of connecting SCSI disk storage, providing higher speeds and far greater numbers of connected devices.
It also added support for any number of "upper layer" protocols, including SCSI, ATM, and IP, with SCSI being the predominant usage.
Fibre Channel Variants
Fibre Channel topologies
There are three major Fibre Channel topologies,
Point-to-Point (FC-P2P). Two devices are connected back to back. This is the simplest topology, with limited connectivity.
Arbitrated loop (FC-AL). In this design, all devices are in a loop or ring, similar to token ring networking. Adding or removing a device from the loop causes all activity on the loop to be interrupted. The failure of one device causes a break in the ring. Fibre Channel hubs exist to connect multiple devices together and may bypass failed ports. A loop may also be made by cabling each port to the next in a ring. Often an arbitrated loop between two ports will negotiate to become a P2P connection, but this is not required by the standard.
Switched fabric (FC-SW). All devices or loops of devices are connected to Fibre Channel switches, similar conceptually to modern Ethernet implementations. The switches manage the state of the fabric, providing optimized interconnections.
There are three major Fibre Channel topologies,
Point-to-Point (FC-P2P). Two devices are connected back to back. This is the simplest topology, with limited connectivity.
Arbitrated loop (FC-AL). In this design, all devices are in a loop or ring, similar to token ring networking. Adding or removing a device from the loop causes all activity on the loop to be interrupted. The failure of one device causes a break in the ring. Fibre Channel hubs exist to connect multiple devices together and may bypass failed ports. A loop may also be made by cabling each port to the next in a ring. Often an arbitrated loop between two ports will negotiate to become a P2P connection, but this is not required by the standard.
Switched fabric (FC-SW). All devices or loops of devices are connected to Fibre Channel switches, similar conceptually to modern Ethernet implementations. The switches manage the state of the fabric, providing optimized interconnections.
Fibre Channel layers
Fibre Channel is a layered protocol. It consists of 5 layers, namely:
FC0 The physical layer, which includes cables, fiber optics, connectors, pinouts etc.
FC1 The data link layer, which implements the 8b/10b encoding and decoding of signals.
FC2 The network layer, defined by the FC-PI-2 standard, consists of the core of Fibre Channel, and defines the main protocols.
FC3 The common services layer, a thin layer that could eventually implement functions like encryption or RAID.
FC4 The Protocol Mapping layer. Layer in which other protocols, such as SCSI, are encapsulated into an information unit for delivery to FC2.
FC0, FC1, and FC2 are also known as FC-PH, the physical layers of fibre channel.
Fibre Channel products are available at 1 Gbit/s, 2 Gbit/s and 4 Gbit/s. An 8 Gbit/s standard is being developed. A 10 Gbit/s standard has been ratified, but is currently only used to interconnect switches. No 10 Gbit/s initiator or target products are available yet based on that standard. Products based on the 1, 2, 4 and 8 Gbit/s standards should be interoperable, and backward compatible; the 10 Gbit/s standard, however, will not be backward compatible with any of the slower speed devices.
[edit] Ports
The following types of ports are defined by Fibre Channel:
E_port is the connection between two fibre channel switches. Also known as an Expansion port. When E_ports between two switches form a link, that link is referred to as an InterSwitch Link or ISL.
EX_port is the connection between a fibre channel router and a fibre channel switch. On the side of the switch it looks like a normal E_port, but on the side of the router it is a EX_port.
F_port is a fabric connection in a switched fabric topology. Also known as Fabric port. An F_port is not loop capable.
FL_port is the fabric connection in a public loop for an arbitrated loop topology. Also known as Fabric Loop port. Note that a switch port may automatically become either an F_port or an FL_port depending on what is connected.
G_port or generic port on a switch can operate as an E_port or F_port.
L_port is the loose term used for any arbitrated loop port, NL_port or FL_port. Also known as Loop port.
N_port is the node connection pertaining to hosts or storage devices in a Point-to-Point or switched fabric topology. Also known as Node port.
NL_port is the node connection pertaining to hosts or storage devices in an arbitrated loop topology. Also known as Node Loop port.
TE_port is a term used for multiple E_ports trunked together to create high bandwidth between switches. Also known as Trunking Expansion port.
Fibre Channel is a layered protocol. It consists of 5 layers, namely:
FC0 The physical layer, which includes cables, fiber optics, connectors, pinouts etc.
FC1 The data link layer, which implements the 8b/10b encoding and decoding of signals.
FC2 The network layer, defined by the FC-PI-2 standard, consists of the core of Fibre Channel, and defines the main protocols.
FC3 The common services layer, a thin layer that could eventually implement functions like encryption or RAID.
FC4 The Protocol Mapping layer. Layer in which other protocols, such as SCSI, are encapsulated into an information unit for delivery to FC2.
FC0, FC1, and FC2 are also known as FC-PH, the physical layers of fibre channel.
Fibre Channel products are available at 1 Gbit/s, 2 Gbit/s and 4 Gbit/s. An 8 Gbit/s standard is being developed. A 10 Gbit/s standard has been ratified, but is currently only used to interconnect switches. No 10 Gbit/s initiator or target products are available yet based on that standard. Products based on the 1, 2, 4 and 8 Gbit/s standards should be interoperable, and backward compatible; the 10 Gbit/s standard, however, will not be backward compatible with any of the slower speed devices.
[edit] Ports
The following types of ports are defined by Fibre Channel:
E_port is the connection between two fibre channel switches. Also known as an Expansion port. When E_ports between two switches form a link, that link is referred to as an InterSwitch Link or ISL.
EX_port is the connection between a fibre channel router and a fibre channel switch. On the side of the switch it looks like a normal E_port, but on the side of the router it is a EX_port.
F_port is a fabric connection in a switched fabric topology. Also known as Fabric port. An F_port is not loop capable.
FL_port is the fabric connection in a public loop for an arbitrated loop topology. Also known as Fabric Loop port. Note that a switch port may automatically become either an F_port or an FL_port depending on what is connected.
G_port or generic port on a switch can operate as an E_port or F_port.
L_port is the loose term used for any arbitrated loop port, NL_port or FL_port. Also known as Loop port.
N_port is the node connection pertaining to hosts or storage devices in a Point-to-Point or switched fabric topology. Also known as Node port.
NL_port is the node connection pertaining to hosts or storage devices in an arbitrated loop topology. Also known as Node Loop port.
TE_port is a term used for multiple E_ports trunked together to create high bandwidth between switches. Also known as Trunking Expansion port.
Fibre Channel Infrastructure
Fibre Channel switches are divided into two classes of switches. These classes are not part of the standard, and the classification of every switch is left up to the manufacturer.
Director switches are characterized by offering a high port-count in a modular (slot-based) chassis with no single point of failure (high availability).
Fabric switches are typically fixed-configuration (sometimes semi-modular) non-redundant switches.
Brocade, Cisco, McData and QLogic provide both Director and fabric switches. If multiple switch vendors are used in the same fabric, the fabric will default to "interoperability mode" where some proprietary advanced features may be disabled.
[edit] Fibre Channel Host Bus Adapters
Fibre Channel HBAs are available for all major open systems, computer architectures, and buses, including PCI and SBus (obsolete today). Some are OS dependent. Each HBA has a unique World Wide Name (WWN), which is similar to an Ethernet MAC address in that it uses an Organizationally Unique Identifier (OUI) assigned by the IEEE. However, WWNs are longer (8 bytes). There are two types of WWNs on a HBA; a node WWN (WWNN), which is shared by all ports on a host bus adapter, and a port WWN (WWPN), which is unique to each port. Some Fibre Channel HBA manufacturers are Emulex, LSI, QLogic and ATTO Technology.
[edit] Fibre Channel References
RFCs
RFC 4369 - Definitions of Managed Objects for Internet Fibre Channel Protocol iFCP
RFC 4044 - Fibre Channel Management MIB
RFC 3723 - Securing Block Storage Protocols over IP
RFC 2837 - Definitions of Managed Objects for the Fabric Element in Fibre Channel Standard
RFC 2625 - IP and ARP over Fibre Channel (Obsoleted by: RFC 4338)
RFC 3831 - Transmission of IPv6 Packets over Fibre Channel (Obsoleted by: RFC 4338)
RFC 4338 - Transmission of IPv6, IPv4, and Address Resolution Protocol (ARP) Packets over Fibre Channel
Drafts
draft-ietf-imss-fc-rtm-mib-00.txt Fibre-Channel Routing Information MIB
draft-ietf-imss-fc-fspf-mib-00.txt MIB for Fibre-Channel's Fabric Shortest Path First Protocol
Other References
Clark, T. Designing Storage Area Networks, Addison-Wesley, 1999. ISBN 0-201-61584-3
Definitions of devices and nodes
Archive Device – e.g. Tape Device, JBOD, …
Fibre Channel switches are divided into two classes of switches. These classes are not part of the standard, and the classification of every switch is left up to the manufacturer.
Director switches are characterized by offering a high port-count in a modular (slot-based) chassis with no single point of failure (high availability).
Fabric switches are typically fixed-configuration (sometimes semi-modular) non-redundant switches.
Brocade, Cisco, McData and QLogic provide both Director and fabric switches. If multiple switch vendors are used in the same fabric, the fabric will default to "interoperability mode" where some proprietary advanced features may be disabled.
[edit] Fibre Channel Host Bus Adapters
Fibre Channel HBAs are available for all major open systems, computer architectures, and buses, including PCI and SBus (obsolete today). Some are OS dependent. Each HBA has a unique World Wide Name (WWN), which is similar to an Ethernet MAC address in that it uses an Organizationally Unique Identifier (OUI) assigned by the IEEE. However, WWNs are longer (8 bytes). There are two types of WWNs on a HBA; a node WWN (WWNN), which is shared by all ports on a host bus adapter, and a port WWN (WWPN), which is unique to each port. Some Fibre Channel HBA manufacturers are Emulex, LSI, QLogic and ATTO Technology.
[edit] Fibre Channel References
RFCs
RFC 4369 - Definitions of Managed Objects for Internet Fibre Channel Protocol iFCP
RFC 4044 - Fibre Channel Management MIB
RFC 3723 - Securing Block Storage Protocols over IP
RFC 2837 - Definitions of Managed Objects for the Fabric Element in Fibre Channel Standard
RFC 2625 - IP and ARP over Fibre Channel (Obsoleted by: RFC 4338)
RFC 3831 - Transmission of IPv6 Packets over Fibre Channel (Obsoleted by: RFC 4338)
RFC 4338 - Transmission of IPv6, IPv4, and Address Resolution Protocol (ARP) Packets over Fibre Channel
Drafts
draft-ietf-imss-fc-rtm-mib-00.txt Fibre-Channel Routing Information MIB
draft-ietf-imss-fc-fspf-mib-00.txt MIB for Fibre-Channel's Fabric Shortest Path First Protocol
Other References
Clark, T. Designing Storage Area Networks, Addison-Wesley, 1999. ISBN 0-201-61584-3
Definitions of devices and nodes
Archive Device – e.g. Tape Device, JBOD, …
Backplane Storage Devices:
1) Controller: Usually located within an enclosure containing storage such as JBOD’s
or SBOD’s. Controllers appear as a target for storage requests from the SAN side (e.g. to host servers). Controllers pass the request as an initiator to the BEL’s. Controllers typically contain FC HBA targets and initiator ASIC logic connected through a mezzanine bus such as PCI.
2) Fabric: The collection of switches and associated ISL’s in a SAN. Fabrics are commonly shown as a cloud in diagrams.
1) Controller: Usually located within an enclosure containing storage such as JBOD’s
or SBOD’s. Controllers appear as a target for storage requests from the SAN side (e.g. to host servers). Controllers pass the request as an initiator to the BEL’s. Controllers typically contain FC HBA targets and initiator ASIC logic connected through a mezzanine bus such as PCI.
2) Fabric: The collection of switches and associated ISL’s in a SAN. Fabrics are commonly shown as a cloud in diagrams.
3) HBA - Host-Bus Adapter: An interface card typically residing in a server that connects the internal bus in the server (e.g., PCI) to the Fibre Channel SAN infrastructure via an SEL
4) HDD - Hard Disk Drive: A storage device typically used in JBOD’s
4) HDD - Hard Disk Drive: A storage device typically used in JBOD’s
5) JBOD - Just a Bunch of Disks or an enclosure that contains HDD’s
5) RAID - Redundant Array of Independent (or Inexpensive) Disks
6) SAN - Storage Area Network: The collection of SEL’s, switches, and ISL’s that connect servers, controllers, tapes and SAN appliances to each other Storage Device – e.g. JBOD, Tape Device, RAID, Media Controller, Translation Device
8) Storage Enclosure – Enclosure of Backplane Storage Devices. e.g. JBOD, …
6) SAN - Storage Area Network: The collection of SEL’s, switches, and ISL’s that connect servers, controllers, tapes and SAN appliances to each other Storage Device – e.g. JBOD, Tape Device, RAID, Media Controller, Translation Device
8) Storage Enclosure – Enclosure of Backplane Storage Devices. e.g. JBOD, …
Definitions of Links
BEL - Back-End Link:
Connects JBODS, RAID, other storage devices, back-end switches,
controller back ends and server back ends using cable assemblies, not
backplanes. Technology like SEL, but typically requires shorter links
and lower data rates.
BPL - Inter-Device Link:
Backplane interconnect for switch blades, internal switch connections,
Blade Servers, ASIC interconnects and related uses. Technology like
IDL, but typically requires longer links and higher data rates.
IDL - Inter-Device Link:
Backplane interconnect for storage peripherals
ISL - Inter-Switch Link:
Connects switches to switches
SEL - SAN Edge Link:
Connects edge switches to servers, controllers, or tapes
Notes:
• A variant is the collected specifications that allow a link to
operate. Variant specifications include encoding scheme,
speeds, signal requirements, return loss, etc. Some variants may
also include connector and interconnect requirements while
others may not. Links only operate under the specifications for a
single variant at a time (although some links may have limited
variant to variant agility).
• Encoding maps with variant, not with speed - 8b10b may be used
at any speed supported by a variant, 64b66b may be used at any
speed supported by a variant (presently only specified for 10 GFC
variants).
• A variant may be used in any application (except backplanes, IDL,
presently only use electrical variants and distances above
approximately 15 meters use only optical variants).
• Switches, controllers, and servers all have the capability of having
multiple ports where the ports may operate at different speeds
(i.e., different variants) in the same switch, controller, or server.
Notes: (Continued)
• Controllers and servers contain the Back End Link and SAN Edge
Link FC Port function (e.g., HBA).
• Switches contain the fabric FC port functions (for both ISL and
SEL ports) and may contain BPLs.
• If the back end interconnect contains one or more switches the
back end interconnect may be called a back end fabric (for
portions that are attached to a back end switch). Both BELs and
BPLs may be used.
• Servers may operate with no SAN edge connections (i.e., only
have direct attached storage). This condition has SEL’s between
the server and the storage but there is no SAN.
• Servers may have multiple HBA’s with each HBA possibly having
multiple ports.
• Tapes are directly attached to edge switches (i.e., not behind
controllers) because tapes are not collocated with the disks and
controllers do not serve any relevant purpose for tapes. Also
controllers may interfere with the streaming requirements of tapes
Fibre Channel-to-SCSI bridges page 85 "... It may sound banal, but in practice the installation of a Fibre Channel SAN is sometimes delayed because the connectors on the cable do not fit the connectors on the end devices, hubs and switches and a suitable adapter is not to hand. A further, initially improbably, but important device is the so-called Fibre Channel-to-SCSI bridge. As the name suggests, a Fibre Channel-to-SCSI bridge creates a connection between Fibre Channel and SCSI (Figure 3.30). These bridges have two important fields of application. First, old storage devices often cannot be converted from SCSI to Fibre Channel. If the old devices are still functional they can continue to be used in the Fibre Channel SAN by the deployment of a Fibre Channel-to-SCSI bridge. Second, new tape libraries in particular often initially only support SCSI; the conversion to Fibre Channel is often not planned until later.With a Fibre Channel-to-SCSI bridge the newest tape libraries can be operated directly in a Fibre Channel SAN and Fibre Channel connections retrofitted as soon as they become available. Unfortunately, the manufacturers have not agreed upon a consistent name for this type of device. In addition to Fibre Channel-to-SCSI bridge, terms such as SAN router or storage gateway are also common. The switch is the control centre of the fabric topology. It provides routing and aliasing, name server and zoning functions. Fibre Channel switches support both cut-through routing and the buffering of frames. In new switches a number of ports between eight and about 250 and a data transfer rate of 200 MByte/s should currently (2003) be viewed as standard. In Fibre Channel SANs that have already been installed, however, a large base of switches exists that still work at 100 MByte/s. "
fontes:
Livro - Storage Networks Explained Basics and Application of Fibre Channel SAN, NAS, iSCSI and InfiniBand
http://www.fibrechannel.org/
http://www.wikipedia.com/
Questões Relacionadas:
31. Em uma Storage Area Network − SAN, para realizar a conversão entre dispositivos SCSI e Fibre Channel, que são interfaces de diferentes padrões elétricos e diferentes protocolos, é necessário o uso de
(A) frames.
(B) bridges.
(C) switches.
(D) hubs.
(E) routers.
Resposta B
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