1

Chapter 1

Data Center Networks 資料中心網路

Course Goal and Objectives

“To perform the conceptual, intermediate, and detailed design of a network infrastructure that supports the network solutions to achieve effective performance, scalability, and availability to meet the desired requirements” Describe how the Cisco Enterprise Network model is used in

the Service Oriented Network Architecture (SONA) framework for designing enterprise networks.

Create conceptual, intermediate, and detailed intelligent network service designs for network management, high availability, security, QoS, and IP multicast.

2

The Hierarchical Model

The foundation of the Cisco network architectures is the hierarchical network model.

Historically used in the design of enterprise LAN and wide area network (WAN) data networks.

A hierarchical model also applies to the infrastructure modules of SONA and the Cisco Enterprise Architecture.

3

The Hierarchical Model

The hierarchical network model provides a modular view of a network, making it easier to design and build a deterministic scalable network.

The hierarchical network structure is composed of the access, distribution, and core layers.

Each layer has its own functions, which are used to develop a hierarchical network design.

4

The Hierarchical Model

Access layer: Used to grant user access to network devices. incorporates switched LAN devices with ports that provide

connectivity to workstations and servers. In the WAN environment, the access layer for teleworkers or

remote sites may provide access to the corporate network across WAN technology.

Distribution layer: Aggregates the wiring closets, using switches

to segment workgroups and isolate network problems in a campus environment. The distribution layer aggregates WAN connections at the edge

of the campus and provides policy-based connectivity.

5

The Hierarchical Model

Core layer (also referred to as the backbone): A high-speed backbone, designed to switch packets as fast as possible.

Because the core is critical for connectivity, it must

provide a high level of availability and adapt to changes very quickly.

It also provides scalability and fast convergence

6

Hierarchical Network

7

The Hierarchical Model Three-layer hierarchical model : Access layer: The devices at the access layer must detect

whether a telecommuter who is dialing in is legitimate, yet must also require minimal telecommuter authentication steps.

Distribution layer: Distribution layer devices control access to resources that are available at the core layer and make efficient use of bandwidth.

Core layer: Core layer devices provide services that optimize communication transport within the network. In addition, core layer devices are expected to provide maximum

availability and reliability.

8

Enterprise Network Design for Cisco Architectures

Cisco developed three overlapping architectures for the enterprise as part of a network architecture and design (Borderless Networks, collaboration, and virtualization (data center and desktop))

9

Enterprise Network Design for Cisco Architectures

Borderless Networks: workers are more mobile. More workers are working

from different locations. (anywhere, anytime, and from any device.)

providing high-performance secure mobile connectivity.

Collaboration:

aims at building a network that integrates all these different means of communication and an infrastructure that is ready to support this mix of multimedia applications.

integrating many different types of communication methods and devices.

10

Enterprise Network Design for Cisco Architectures

Data center virtualization: Data centers contain the back-end services and data

that enable the applications that are used in the enterprise.

To ensure that applications can be scaled as demand changes, it is important that data centers be built in a cost-effective, energy-efficient, resilient and scalable manner.

provisioning data storage and computing resources to applications in a highly scalable and resilient manner by leveraging virtualization technology.

11

Enterprise Network Design for Cisco Architectures

12

Review of Cisco SONA Cisco SONA uses the extensive product line, services,

proven architectures, and experience of Cisco and its partners to help enterprises achieve their business goals.

13 Service Oriented Network Architecture

Benefits of SONA

14

Review of Cisco SONA SONA outlines these three layers: 1. The networked infrastructure layer: Customers is to

have anywhere and anytime connectivity.

2. The interactive services layer: enables efficient allocation of resources to applications and business processes delivered through the networked infrastructure.

3. The application layer: Customers is to meet business requirements and achieve efficiencies by leveraging the interactive services layer.

15

Infrastructure Services

16

Infrastructure Services Application Service:

Identity services: Maps resources and policies to the user and device

Mobility services: Allows users to access network resources regardless of their physical location. Wireless services support mobile clients, and integrate with the wired network.

Storage services: Provides distributed and virtual storage across the infrastructure

Application-Oriented Networking: Compute services: Connects and virtualizes compute resources

based on the application Security services: Increase the integrity of the network by

protecting network resources and users from internal and external threats.

Voice services: Delivers the foundation by which voice can be carried across the network, such as security and high availability

17

Network Services Network management High availability: Ensures end-to-end availability

for services, clients, and sessions. QoS: Manages the delay, delay variation (jitter),

bandwidth availability, and packet loss parameters to meet the diverse needs of voice, video, and data applications.

IP multicasting: Delivering a single stream of information that is intended for many corporate recipients and homes throughout the transport network.

18

Network Applications Cisco Unified Communications: Includes voice,

video, and web conferencing solutions. Cisco Digital Media Systems: Includes applications

such as Cisco Digital Signage, which delivers video and application content to many large display monitors that are placed throughout the organization.

Cisco IP Video Surveillance: Provides real-time monitoring of the environment, people, and assets and provides recording for investigative purposes.

Cisco TelePresence: Provides a deeply immersive video experience. This application is key to the new generation of communication

experience and is becoming pervasive in many enterprises

19

Cisco Enterprise Architectures

20

Cisco Enterprise Architectures

Campus module: Combines a core infrastructure of intelligent switching and routing with tightly integrated productivity-enhancing technologies, including Cisco Unified Communications, mobility, and advanced security.

Edge architecture: Offers connectivity to voice, video, and data services outside the enterprise. QoS, service levels, and security are the main issues in the

Enterprise Edge module.

WAN and MAN module: offers the convergence of voice, video, and data services over a single Cisco Unified Communications network.

21

Summary

Cisco SONA is the enterprise framework for building intelligence in the network: Layer 1 is the integrated infrastructure layer. Layer 2 is the interactive services layer. Layer 3 is the applications layer.

22

Virtual Machine Systems

Question Can a “small” operating system simulate the

hardware of some machine so that Another operating system can run in that

simulated hardware? More than one instance of that operating system

run on the same hardware at the same time? More than one different operating system can

share the same hardware at the same time? Answer: Yes

CS502 Spring 2006

Solution – Virtual Machine

A virtual machine provides interface identical to underlying bare hardware i.e., all devices, storages, memory, page

tables, etc.

Virtual Machine Operating System creates illusion of multiple processors Each VM executes independently No sharing, except via network protocols

History – CP67 / CMS

IBM Cambridge Scientific Center Ran on IBM 360/67

Alternative to TSS/360, which never sold very well

Replicated hardware in each “process” Virtual 360/67 processor Virtual disk(s), virtual console, printer, card reader, etc.

Cambridge Monitor System (CMS) A single user, interactive operating system

Commercialized as VM370 in mid-1970s

History (cont.)

Various other attempts with other machines

VMware Workstation Servers (for IT centers)

“Classic” Virtual Machine Copy of a real machine

“Any program run under the VM has an effect identical with that demonstrated if the program had been run in the original machine directly” 1

Isolated from other virtual machines “…transforms the single machine interface into the illusion of

many” 2 Efficient

“A statistically dominant subset of the virtual processor’s instructions is executed directly by the real processor” 2

Also known as a “system VM”

1 “Formal Requirements for Virtualizable Third-Generation Architectures”, G. Popek and R. Goldberg, Communications of the ACM, 17(7), July 1974

2 “Survey of Virtual Machine Research”, R. Goldberg, IEEE Computer, June 1974

Classic Virtual Machines Virtualization of instruction sets (ISAs)

Language-independent, binary-compatible (not JVM)

70’s (IBM 360/370..) – 00’s (VMware, Microsoft Virtual Server/PC, z/VM, Xen, Power Hypervisor, Intel Vanderpool, AMD Pacifica …)

ISA+ OS + libraries + software = execution environment

Definitions

Host Operating System: The operating system actually running on the

hardware Together with virtualization layer, it

simulates environment for … Guest Operating System:

The operating system running in the simulated environment

E.g., the one we are trying to debug

Process vs. System VMs In Smith and Nair’s

“The architecture of Virtual machines”, Computer, May 2005

Must Virtual Machine be Replica of Host Machine?

No, virtualization layer can simulate any architecture

Typically used for debugging specialized systems Real-time systems, niche products, etc.

Guest architecture does not even have to

be real hardware!

Example – Page tables Suppose guest OS has its own page tables

Then virtualization layer must Copy those tables to its own Trap every reference or update to tables and

simulate it

During page fault Virtualization layer must decide whether fault

belongs to guest OS or self If guest OS, must simulate a page fault

Likewise, virtualization layer must trap and simulate every privileged instruction in machine!

Virtual Machines (cont.)

The resources of the physical computer are shared to create the virtual machines CPU scheduling can create the appearance that each

user has own processor Spooling and a file system provide

virtual card readers, virtual line printers Disk partitioned to provide virtual disks A normal user time-sharing terminal serves as the

virtual machine operator’s console

Virtual Machines (cont.)

Virtual-machine concept provides complete protection of system resources Each virtual machine is isolated from all other

virtual machines. However, it does not directly share the resources

Virtual-machine system is a good vehicle for operating-systems research and development. System development is done on the virtual machine

does not disrupt normal operation Multiple concurrent developers can work at same

time

Virtual Machines (cont.)

Non-virtual Machine Virtual Machine

(a) Nonvirtual machine (b) virtual machine

CS502 Spring 2006

Virtual Machines (cont.)

Some hardware architectures or features are impossible to virtualize Certain registers or state not exposed Unusual devices and device control Clocks, time, and real-time behavior

On-demand computing

Embodiments: Data-centers Grid-computing

“coordinated resource sharing and problem solving in dynamic, multi-institutional virtual organizations”

In the “The anatomy of the Grid,” Foster et. Al Local control, decentralized management Open general-purpose standards Non-trivial QoS

Data Center

Network Infrastructure

Server Farm

Resource sharing Traditional computing/data center solutions:

Multitask/multiuser operating systems, user accounts, file systems … Always available but static configurations

Sharing possible if apps run on similar execution environments

Centralized administration Tight control on security, availability, users, updates, etc

Distributed Grid/datacenter requirements Multiple administrative domains

Different policies and practices at each domain Many environments possible Dynamic availability

Must run all kinds of applications Application user will neither trust unknown users sharing the same

resource nor redevelop application to run in different environments Resource owner will neither trust arbitrary users nor change

environment for others’ applications

A B C

A B C

Ocean

1 user, 1 app, several environments

+CH3D +ArcView

Compute Server

Compute Server

Compute Server

Compute Server

Compute Server

Compute Server

Grid

Slide provided by M. Zhao

Many users, 1 app, many environments

Compute Server Compute Server Compute Server

Compute Server

Compute Server Compute Server

+CH3D VM

+ArcView

VM

Grid Middleware

+CH3D

+CH3D +CH3D

+ArcView

+CH3D Ocean

+ArcView

+ArcView

+ArcView

+CH3D

+ArcView

Slide provided by M. Zhao

Challenge: VM State Transfer

Compute Server Compute Server Compute Server

Compute Server

+CH3D VM

+ArcView

VM

Grid Middleware

VM State Servers + ArcView

Ocean

Dynamic, efficient transfer of large VM state is important

+ CH3D

+CH3D

+ArcView

+CH3D

+ArcView

+CH3D

+ArcView

Many users, apps and environments

Slide provided by M. Zhao

Virtualization Technology for Grids Resource virtualization technology

Enables a resource to simultaneously appear as multiple resources with possibly different functionalities Polymorphism, manifolding and multiplexing

Virtual networks, data, applications, interfaces, peripherals, instruments … Emergent technologies

Public network A

Private network C

Private network B

Public network D

Internet

VR

Virtual network

Virtual network

Virtual network

Virtual network

R N F

Router

NAT

Firewall

Virtual Router

H Host

VH1 to VH2

VH3 to VH4

H N H4

H2 H

H

VH2

VRA

VH4

VH

VRC

R

F H3

H1 H

VRB

VH

N

VH1

VRD

H

H

VH3

Virtual Space

Physical Space

Virtual networks Logical links:

• multiple physical links, routing via native Internet routing • tunneling, virtual routers, switches, … • partial to total isolation

Slide provided by M. Tsugawa

Data/File Virtualization

NFS Client NFSD

Server

Mountd

Client

NFS Server ‘S’

Export /home to all uids on compute server C

Compute Server ‘C’

mount S:/home

Export /home/user_A to shadow1 on C

NFS Client NFSD

Server Client

Mountd

mount S:/home/user_A

GVFS Proxy

GVFS Proxy

A Grid-building Recipe

Virtualize to fit needed environments Use services to generate “virtuals” Aggregate and manage “virtuals” Repeat as needed

• Net result: • Users interact with virtual entities provided by services • Middleware interacts with physical resources

Architectural Components of VM Service

VM Creation Request from Client

(1) VM Request

(6) VM ID

(2) Request Estimate

(3) VM Creation Cost

(4) Create VM

(5) VM ID

mcnabb

vws010

VMPlant Daemon

brady

vws001

VMPlant Daemon

favre

vws005

VMPlant Daemon

mcnair

vws002

manning

vws003

VMShop (VMArchitect VMCreator, VMCollector, VMReporter)

Host OS (VMPlant) Host OS (VMPlant) Host OS

(VMPlant)

VMPlant Daemon

Slide provided by Arijit Ganguly

Create VM Steps Clone VM

Instantiate a new container Fast copying of a base VM image

Virtual disk Suspended memory (if available)

Configure VM Execute scripts/jobs inside container to tailor to a

particular instance Communication crossing container boundaries to provide

inputs/retrieve outputs

Destroy VM Terminate container, delete non-persistent state

User-level Extensions

kernel NFS server

proxy

VM state server S

WAN

Compute server C

VMM

Client-side proxy disk caching

buffer block- based cache

proxy

Application-specific meta-data handling Encrypted file system channels and cross-domain

authentication

[Zhao, Zhang, Figueiredo, HPDC’04]

file- based cache

disk mem

VM state

VMware – Modern Virtual Machine System

Founded 1998, Mendel Rosenblum et al. Research at Stanford University

VMware Workstation Separates Host OS from virtualization layer Host OS may be Windows, Linux, etc. Wide variety of Guest operating systems < $200

CS502 Spring 2006

VMware Architecture

VMware Server

Free version released in 2006 http://www.vmware.com/products/server/ Runs on any x86 server hardware and OS Windows Server and Linux Host OS’s

Partition a physical server into multiple virtual server machines

Target market – IT centers providing multiple services Allows separate virtual servers to be separately configured

for separate IT applications Portability, replication, etc.

VMware Server ESX

Total decoupling between hardware and applications

High-end, high-performance IT applications Oracle, SQL Server, Microsoft Exchange server,

SAP, Siebel, Lotus Notes, BEA WebLogic, Apache

Dynamically move running application to different hardware

Maintenance, hardware replacement Provisioning new versions, etc.

VMware ESX is an enterprise-level computer virtualization product offered by VMware

The Java Virtual Machine

Own idealized architecture Stylized machine language

Byte codes

Readily available interpreter