Network Architecture Models

Telvis Calhoun

CSc 8320

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.

Architecture depends on the category.

Architectures: Peer-to-Peer Each node is a producer and consumer of an implemented

service Architectures [Ge, Z., et al, April 2003]

Centralized Indexing Architecture (CIA) Central server coordinates participating nodes and maintains an index

of all available resources. Distributed Indexing with Flooding Architecture (DIFA)

No central server. Each node maintains an index of local resources. A limited scope query message is flooded to the network when a peer

wants to locate a resource Distributed Indexing with Hashing Architecture

Eliminates flooding Systematically distributes the file indices among participating nodes Queries are routed directly to the node responsible for a subset of the

file index.

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: Client-Server

Workstation-server model [Chow, 1997] Stand-Alone Workstation Diskless Workstation

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]

Wired Network Interfaces

Hardware Interconnections Point-to-Point – Two directly connected nodes Multipoint links – collection of nodes communicate via a

common bus or interconnected networks (switches)

Bus Based: IEEE 802 LAN Ethernet: Token Bus Token Ring Fiber Distributed Data Interface (FDDI) Distributed Queue Dual Buses (DQDB)

Wired Interfaces: Ethernet Family of local-area network (LAN) products covered by the

IEEE 802.3 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.

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

802.4: Token Bus802.5: 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: 802.11

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 802.15.4 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]

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 2003. Twenty-Second Annual Joint Conference of the IEEE Computer and Communications Societies. IEEE Volume 3, 30 March-3 April 2003 Page(s):2188 - 2198 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. 2006 Page(s):801 - 806

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