Network Architecture Models Niranjan Rao Julapelly

Outlines Introduction System Architecture Communication Network References

Distributed Computing "Distributed" or "grid computing" in general is a special type of parallel computing which relies on complete computers (with onboard CPU, storage, power supply, network interface, etc.) connected to a network by a conventional network interface, such as Ethernet. This is in contrast to the traditional notion of a supercomputer, which has many CPUs connected by a local high-speed computer bus.parallel computingEthernet supercomputercomputer bus

Distributed System Categories Multiple computer systems collaborating to deliver a single application ▫Can be broadly applied to high-performance computing (HPC) whereby multiple computers, commonly called clusters, collaborate to solve a single problem Multiple applications collaborating together as a system ▫Can be broadly applied to application integration whereby multiple discrete applications receive a copy of “some” data and process the data accordingly.

Distributed Service Distributed Service depend on the system architecture and the underlying communication network. In the upper level, system architecture is an abstract description of major components and their relation In the lower level, network architecture specifies the communication facilities

Outlines Introduction System Architecture Grid Peer-to-Peer Model Client-Server Communication Network References

Architectures: Grid Integrates and coordinates resources and users that live within different control domains Built from multi-purpose protocols and interfaces that address such fundamental issues as authentication, authorization, resource discovery, and resource access. Allows its constituent resources to be used in a coordinated fashion to deliver various qualities of service, (e.g. response time, throughput, availability, and security) [Foster, 2002]

Architectures: Peer-to-Peer Model In this model, end users share resources in a peer style, potentially acting as both CLIENT and SERVER Advantages: 1. removes single point failure and associated performance bottlenecks 2. releases the network traffic overhead by providing service locally

P2P Categories P2P were classified into three different categories: 1. Centralized P2P systems 2. Decentralized structured P2P systems (there is no central server and peers are structured according to some strict rules) 3. Decentralized unstructured P2P systems

Architectures: Client-Server Workstation-server model [Chow, 1997] ▫A work station may serve as a Stand-Alone computer or as a part of an overall network ▫Some workstations are Diskless Workstation, all file and boot services are supported by the network

Architectures: Client-Server Processor-Pool model ▫Most workstations are idling at any instance in time. ▫Collects all processing power in Processor Pool Server ▫Users access a virtual single computer system with intelligent terminals

HPC Technology: Remote Direct Memory Access (RDMA) Allows data to move directly from the memory of one computer into that of another without involving either one's operating system.

HPC Technology: Cisco® Infiniband 20-Gbps bandwidth Transport functions are all implemented in hardware that offloads all communications tasks such as reliable, in-order delivery and multiplexing, which allows more CPU cycles to be spent on processing rather than communications. [Cisco, 2006] Has RDMA implementation

HPC Technology: SCSI RDMA Protocol Transfers data using SCSI (Small Computer System Interface) using an RDMA communication service. [Intel, 2002]

Outlines Introduction System Architecture Communication Network Wired Network Wireless Network References

Communication Network The existence of multiple computer systems in a distributed system implies the need to interconnect these computers System components may be connected by point- to-point or multipoint communication channels

Communication Network Point-to-point links are direct connections between pairs of computer nodes Multiple links allow the connection of nodes into a cluster and are usually implemented by using common buses or interconnection networks (switches)

Wired Interfaces: Ethernet Family of local-area network (LAN) products covered by the IEEE standard that defines CSMA/CD protocol ▫Carrier sense—Each station continuously listens for traffic on the medium to determine when gaps between frame transmissions occur. ▫Multiple access—Stations may begin transmitting any time they detect that the network is quiet (there is no traffic). ▫Collision Detect – Execute a random backoff before retransmission.

Wired Interfaces: Ethernet Three data rates are currently defined for operation over optical-fiber and twisted-pair cables: ▫10 Mbps—10Base-T Ethernet ▫100 Mbps—Fast Ethernet ▫1000 Mbps—Gigabit Ethernet

Wired Interfaces: Ethernet Local area networks can be connected to form a Metropolitan Area Network (MAN) or a Wide Area Network (WAN) Bus Based: IEEE 802 LAN ▫Ethernet: ▫Token Bus ▫Token Ring ▫Fiber Distributed Data Interface (FDDI) ▫Distributed Queue Dual Buses (DQDB)

802.4: Token Bus 802.5: Token Ring Utilizes Token Passing: ▫Move a small frame, called a token, around the network. Possession of the token grants the right to transmit. ▫If a node receiving the token has no information to send, it passes the token to the next end station. ▫Each station can hold the token for a maximum period of time. Data Rate: 4.16 Mbps A token bus network is very similar to a token ring network, the main difference being that the endpoints of the bus do not meet to form a physical ring.

FDDI - Fiber Distributed Data Interface FDDI uses dual-ring architecture with traffic on each ring flowing in opposite directions (called counter-rotating). During normal operation, the primary ring is used for data transmission, and the secondary ring remains idle. Optical Fiber (FDDI) or Copper Wire (CDDI) Several FDDI Station-Attachment Types 100 Mbps

Wireless: Specification are wireless standards that specify an "over-the-air" interface between a wireless client and a base station or access point, as well as among wireless clients. Data Rates up to 54 Mbps Can operate in Infrastructure (base station) or peer- to-peer mode (ad-hoc). Commonly used in MANETs

Wireless: Zigbee Based on standard for low-complexity and low-power consumption wireless connectivity. Provides Mesh routing capability (based on AODV) Commonly used in wireless sensor networks and industrial automation. [Kwang, 2006]

Outlines Introduction System Architecture Communication Network References

Chow, Randy, et. al.,Distributed Operating Systems & Algorithms, Addison Wesley, March 18, 1997 Ge, Z.; Figueiredo, D.R.; Sharad Jaiswal; Kurose, J.; Towsley, D.; Modeling peer-peer file sharing systems, INFOCOM Twenty- Second Annual Joint Conference of the IEEE Computer and Communications Societies. IEEE Volume 3, 30 March-3 April 2003 Page(s): vol.3 Kwang Koog Lee; Seong Hoon Kim; Yong Soon Choi, A Mesh Routing Protocol using Cluster Label in the ZigBee Network; Mobile Adhoc and Sensor Sysetems (MASS), 2006 IEEE International Conference on Oct Page(s): Foster, Ian, What is a Grid? A Three Point Checklist, Argonne National Laboratory & University of Chicago, July 20, 2002 Enterprise Distributed Systems and Infiniband, Cisco 2006 SCSI RDMA Protocol (SRP), Intel 2002