Managing Bandwidth

Bandwidth is finite but the demand for bandwidth is not. With organizations

putting up more and more applications and services, which are centralized on the

network, bandwidth is getting consumed very fast. Even medium sized enterprises

in India are getting hooked onto the net and are fast catching up on services

delivered through the net. All this traffic is causing an enormous amount of

strain on the networks, which are bursting at their seams. The result–unsatisfied

users.

Today, emerging Internet applications are both bandwidth intensive and time

sensitive. They often require support for voice, video and multimedia, which

takes up more and more bandwidth. And since multiple users and applications

access almost all network resources, the available bandwidth must be shared.

While most organizations in India have sufficient bandwidth to cater to their

average requirements, the response time is very poor, mainly due to the lack of

bandwidth management. Using the tools available for managing bandwidth, a good

IT manager can ensure that all applications keep running smoothly and users are

satisfied. This also helps in cutting costs.

The quality or quantity of available bandwidth at any given moment cannot be

predicted. Bandwidth reservation removes this unpredictability by allowing

applications to reserve the bandwidth and quality of service required. It is

equally difficult to control how the available bandwidth is shared. It is

possible for an application or a user to control the available bandwidth,

preventing other applications or users from using the network. This leads to

networks being over built, providing additional capacity, at additional cost.

This would not be necessary if bandwidth allocation could be controlled.

Bandwidth Distribution

Typically, an organization would be hooked up on a LAN at the branch or

central office. Hence, unless there is a very complex application running on the

LAN, which hogs a lot of bandwidth, a LAN does not require management per se.

This LAN, in turn, is connected to the Internet pipe through a gateway. It is at

this point that the capacity crunch strikes. Hence, it becomes imperative that

this capacity is utilized to its fullest, while giving the best response time.

Traffic can be monitored in a variety of ways, but the two most common

methods are–user-based and protocol-based. Typically, a service or an

application on the network would be using a particular protocol.

Intranets Combine Internet Technology with Corporate Network Control

Intranet deployment requires an

existing network that supports the TCP/IP protocol suite and related Internet

applications. TCP/IP provides the fundamental set of communication protocols

that permit basic connectivity between networks and individual desktop systems.

Internet applications (e-mail, Web browsing, file transfer, terminal emulation,

etc.) provide the tools and services that allow workers to share information

across one or more LANs, a WAN, or the Internet. These applications

significantly increase demand for bandwidth.

Intranet Applications Increase Bandwidth Demands

Of all the Internet applications, the

Web browser has been the greatest driver of corporate intranet development. They

have been called the Swiss army knife interface to information because they are

platform independent and provide users with transparent access to FTP, Gopher,

Telnet, Network News, e-mail, online content search, and interactive database

queries. The tremendous popularity of Web browsers lies in their potential to

act as the universal client interface for any client/server application.

Emergence of TCP/IP

Over the years, efforts to simplify and

consolidate network operations has reduced the number of different protocols

running across enterprise networks, with TCP/IP emerging as the clear winner.

Looking back, there are a number of reasons for the inevitable emergence of

TCP/IP as the winner of the multi-protocol sweepstakes:

• TCP/IP has a solid track record
  
  based on years of operational experience on the Internet.

• TCP/IP was originally designed to
  
  provide efficient communication across both LANs and WANs; over the years,
  
  it has demonstrated its ability to scale to global proportions.

• TCP/IP provides universal
  
  information exchange between all types of end systems PCs, Macintosh
  
  computers, Unix platforms, supercomputers (Crays, NECs), mainframes (IBM,
  
  Tandem, etc.), minicomputers (HP3000, AS/400), etc.

• TCP/IP has developed a robust set
  
  of network management tools & #151; Simple Network Management Protocol (SNMP),
  
  Remote Monitoring (RMON), RMON2 & #151; and network management platform
  
  support from leading vendors.

• TCP/IP has an active development
  
  community (the Internet Engineering Task Force or IETF) to continually
  
  enhance and extend existing tools, develop new tools, and extend the
  
  protocol suite.

• Internet applications run over
  
  TCP/IP, not IPX, AppleTalk, DECnet, OSI, or VINES. To deploy native Internet
  
  applications on desktops, the network must be running TCP/IP.

Explosion of Corporate Intranets

The public Internet is based on TCP/IP

technology that has been evolving for the past 30 years into a remarkable tool.

Until recently, the riches of the Internet were not readily available to novice

computer users due to the lack of a user interface. It was the development of

easy-to-use, point-and-click Web browsers like NCSA Mosaic, Netscape Navigator,

and Microsoft Internet Explorer that fueled the recent growth of the Internet

and the World Wide Web.

Web browsers were first adopted by

organizations to support inter-enterprise communications across the Internet.

Typically, an enterprise developed an Internet presence and deployed a Web

server to provide sales, marketing, and support information to external users.

As time passed, organizations realized the financial and strategic benefits of

using Web technology to provide information to internal users; the corporate

intranet. Many believe that the next evolutionary step will be the development

of secure extended intranets where Web technology is used to reach key external

customers and suppliers and to support all business transactions electronically.

Common Intranet Information Sharing Model

According to Forrester Research, 22

percent of the Fortune 1000 companies currently use Web servers for internal

applications, and another 40 percent are seriously considering their deployment

in the near future. Zona Research predicts that by the year 2000 there will be

nearly 3.3 million private intranet servers, as opposed to 650,000 for the

public Internet. There are many forces driving organizations to migrate their

internal information management systems to the intranet model:

• Intranets flatten the information
  
  delivery system within an organization, delivering content on demand. They
  
  foster the rapid exchange of information required to support reduced product
  
  life cycles, increased cost pressures, demand for customer service, and
  
  rapidly changing markets.

• The information on Web servers has
  
  the potential to be the latest and most accurate. Information can be
  
  cross-linked to provide point-and- click access to any other document within
  
  the organization or around the world.

• Intranets are based on open
  
  standards. This plays an important role in overcoming problems with
  
  incompatible computing environments (UNIX, MacOS, DOS, Windows 3.1, Windows
  
  95, Windows NT, OS/2, VMS, etc.) that previously prevented universal access
  
  to information.

• Desktop browsers can be modified to
  
  function as the client interface for almost any client/server application.
  
  Since they are intuitive and extremely easy to use, browsers do not require
  
  a large investment in training.

• Intranets provide a high level of
  
  security. Many organizations do not have a direct connection to the global
  
  Internet, and if they are do, they can protect their intranet using an
  
  Internet firewall system. Java-enabled browsers support strong memory
  
  protection, encryption and signatures, and run-time verification.

Internet Firewall System

The prevailing desktop-centric model of

computing is implemented by the deployment of heterogeneous fat clients. A fat

client is a desktop system that is loaded with a complex operating system, local

configuration files, a number of popular desktop



applications, and a variety of incompatible client applications for each network
services. In contrast, the network-centric model of computing motivated by the

corporate intranet is based on the deployment of thin clients with Java and/or

ActiveX-enabled browsers.

By deploying thin clients, network

managers can greatly reduce the complexity and administrative expense of running

their networks. Sun Microsystems estimates that the annual cost of operating

Java-based clients will be less than $2,500/desktop, compared to a $10,000 to

$15,000/desktop range for today’s fat clients.

Thin Client Implementing a Java Webtop

Internet applications provide better

performance within a corporate intranet than they do across the Internet. Most

individual systems are connected to the Internet at data rates from 28.8/33.6

Kbps to the emerging 56 Kbps dial rates. Corporate users may have access at

rates ranging from 128 Kbps (ISDN BRI) up to T1/E1 Mbps, but this may still seem

relatively slow since the bandwidth is shared by many other workstations. In

contrast, corporate intranets generally provide each desktop with access to

local Web servers at data rates of 10/100 Mbps.

Intranets are based on inexpensive

technology that is widely deployed in many private networks. If the enterprise

has TCP/IP on its network, it can easily install Web servers and browsers. This

allows organizations to slowly migrate to the intranet model without discarding

a single computing platform or application.

Challenges for Network Managers

In many enterprises, the deployment of

internal Web servers is a grassroots operation. The proliferation of HyperText

Markup Language (HTML) editors has eased the burden of content creation, and Web

servers are springing up all over organizations, in many cases without the

knowledge or cooperation of the local network administrator or the traditional

IS department. Network administrators who have been accustomed to carefully

planning for traffic flows and bandwidth requirements associated with the

rollout of a network operating system upgrade or a new client/server application

are facing new challenges with the rapid migration to the intranet model:

• Internal Web sites with large
  
  graphic or multimedia content will make increasing bandwidth demands on the
  
  corporate infrastructure. The total volume of network traffic will grow as
  
  the content from bandwidth-intensive pages is transmitted across the
  
  organization’s infrastructure.

• The rollout of new applications
  
  based on Java and/or ActiveX applets can result in additional bandwidth and
  
  performance challenges. In the current client/server model, specialized
  
  client software is preinstalled on the user’s hard drive for each server
  
  that needs to be accessed. In the intranet model, applets are downloaded
  
  from the Web server to the client as they are needed. Although this greatly
  
  reduces LAN administrative costs, it can cause network congestion and slow
  
  response times.

• Intranet traffic flows will be
  
  impossible to predict and constantly changing. Since the goal of the
  
  intranet is to enable free exchange of information, network managers will
  
  not be able to predict in advance where the traffic bottlenecks will appear.
  
  In contrast to the traditional client/server model, in which large pipes can
  
  be provisioned to provide adequate bandwidth at the core of the network,
  
  user-developed Web servers are typically located on shared media at the edge
  
  of the network. The infrastructure at the periphery may not have sufficient
  
  capacity to support access from clients located across the enterprise. In
  
  addition, narrow WAN communication pipes may experience increased traffic
  
  volumes. Intranets can result in severe network congestion and performance
  
  problems at random locations across the enterprise network infrastructure.

• All of these changes will have a
  
  negative impact on the performance of existing client/server and legacy
  
  applications. These applications must now fight for basic bandwidth in a
  
  network environment in which there are increasing traffic volumes and
  
  unpredictable/unstable loads.

Supporting Intranet Applications

In an Intranet environment, it is

imperative that network managers deploy RMON and RMON2 probes to gather baseline

information about traffic flows and application trends. RMON and proactive

monitoring are the keys to optimizing existing LAN and WAN resources, uncovering

bottlenecks before they appear, establishing policies regarding the use of

applications on the enterprise intranet, and making wise decisions about

capacity planning and future growth.

After potentially disruptive trends are

discovered via RMON/RMON2, network managers have several options meeting the

challenges to efficient network operation. They can provide additional LAN

bandwidth and improve performance by deploying layer 2 switches at the network

edge. They can provide increased traffic control and packet throughput by

deploying intelligent switches with Fast IP at the network core. Finally, they

can use bandwidth-grooming features to overcome bottlenecks resulting from

increased bandwidth demands on narrow WAN links.

Chuck Semeria, Courtesy: 3Com



For all further information, email at Sayan_Ghosh@3Com.com