Comparison of LAN-Based and Client/Server E-mail Technologies

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Comparison of LAN-Based and Client/Server E-mail Technologies (cc:Mail Versus Domino, Exchange, Netscape, and Year 2000)

by Ron Herardian
©1998 Global System Services Corporation (GSS)

LAN-based e-mail is a technology where files stored on a general-purpose file server are accessed by multiple workstations (users, Routers, admin programs, etc.). In LAN-based e-mail there is no server process interacting with client software: the locus of processing logic is within the workstations. Client/server systems invert the LAN-based model by moving the vast majority of processing logic to the server. For e-mail systems, these two opposing architectural models have implications for scalability, reliability, manageability, and extensibility. This article delves into the limitations of LAN-based e-mail technologies such as Lotus cc:Mail as compared with newer, client/server e-mail technologies represented by products such as Domino, Exchange, and Netscape messaging.

Overview

Counter-intuitively, the cc:Mail client applications are not data communications applications but file-based, non-client/server, database applications. The cc:Mail client software has no awareness of the network but instead uses standard workstation file I/O (this is why the meanings of so-called NFT errors are inherently ambiguous). The cc:Mail client applications operate at OSI Reference Model layer 7. Obvious exceptions are Router-to-Router communications via network protocols although the Routers themselves interact with the post office at OSI RM layer 7 as does all cc:Mail client and server software which operates on the database.

In a traditional cc:Mail system there is no cc:Mail code actively running on the file server itself--there are only passive files stored on the server. The technology is based on the interoperability and data transparency of access to files on a file server (file sharing), a technology that developed and became popular during the 1980s, the heyday f Novell NetWare.

Limitations of LAN-Based E-Mail:

Despite its popularity there are several limitations to LAN-based e-mail technology, three of which are of particular importance when comparing LAN-based e-mail with client/server solutions such as Domino, Netscape, and Exchange.

LACK OF SCALABILITY: Although, theoretically, you can have 1000 or more users per post office and file server, in practice you cannot because the amount of data is too large to manage and the file I/O load on the server and network can be problematic for server configurations that could possibly realize any cost savings over client/server solutions.

Large numbers of post offices are difficult to manage and maintain because they involve many different interrelationships. Because each system component has relationships to other components, the complexity of such systems can grow exponentially as the system grows, thus becoming unmanageable without radical consolidation and re-design (refer to the GSS Crash Course for cc:Mail Administrators or to the Lotus cc:Mail Field Support Services Advanced cc:Mail Support Seminar), which only alleviates but does not actually solve the fundamental scalability problems of LAN-based technology. Administration. management, and monitoring of so distributed a system is often problematic.

DATA CORRUPTION: File sharing databases suffer from the uncorrectable flaw that any workstation or any number of server or network errors can corrupt a database impacting many users and causing costly down time and data loss as well as a strain on IT staff. This is because the technology requires that workstations directly modify the shared data. This fundamental architectural vulnerability of LAN-based w-mail cannot be removed.

LIMITED EXTENSIBILITY: Due to the lack of server logic, because there is no code or server-side processing, in a typical cc:Mail installation the system is not extensible to include features like workflow. In a typical cc:Mail system, for example, all of the processing logic resides on client workstations thus any add-on functionality, such as Lotus Organizer, must also be implemented on the client-side.

Add on components require back-end processing which means that machines and processes like the Organizer agent proliferate. These add-on, back-end components can be numerous, are not integrated, share no common administration, management, or monitoring framework, and contribute overall complexity of the system as it grows.

Why Client/Server Systems are Superior:

TECHNOLOGY: Client/server systems consist of a server process which interacts with client applications directly over the network using network protocols such as TCP/IP (generally OSI RM layer 4). Client/server applications are true data communications applications because they use network protocols directly rather than relying on simple file I/O.

SCALABILITY: Client/server systems do not have the overhead of workstation file I/O, thus they can accommodate many more users per server, e.g., 2000-5000 users per server.

DATA INTEGRITY: In a client/server system, the only application that 'touches' the data store is the server process thus error conditions on workstations or networks cannot corrupt the data store as they do in LAN-based technology.

EXTENSIBILITY: Client/server systems such as Domino, Exchange, and Netscape/iPlanet servers share a common architecture or a common set of standards and technologies that allow these products to be extended. New functionality can be implemented at the server and tightly integrated into the server's existing administration. management, and monitoring framework.

Conclusions

LAN-based e-mail is a technology appropriate for small numbers of users with simple requirements and for companies that are today deploying LANs for the first time as is the case in certain vertical industries and in less technologically advanced regions of the world. However, the vast majority of large and medium-sized companies in the US, Europe, and in parts of Asia are likely to find a compelling business case for newer, client/server e-mail technologies.

Most companies that are today making decisions about upgrading LAN-based e-mail systems versus migrating to systems such as Domino, Exchange, and Netscape will achieve a superior return on investment by migrating away from LAN-based e-mail rather than upgrading current systems for year 2000 compatibility.

References

Why LAN-Based E-Mail is Obsolete (and What it Means for Lotus cc:Mail Customers), by Ron Herardian, ©1998 Global System Services Corporation (GSS)
How cc:Mail Interfaces with the Network, by Ron Herardian, ©1995 Global System Services Corporation (GSS)
Messaging Versus Groupware, by Ron Herardian, ©1995 Global System Services Corporation (GSS)
Overview of Migration Issues for cc:Mail Customers, by Ron Herardian, ©1998 Global System Services Corporation

About GSS

Global System Services Corporation (GSS) is the leading provider of consulting and professional services for large-scale and distributed infrastructure systems such as email and messaging, directory services, groupware, and wireless solutions. GSS customers include Fortune 500 companies, large services providers and telecom companies, government agencies, major messaging product vendors, and innovative technology startups.

GSS provides a complementary suite of services including strategic technology consultation and competitive vendor and product analysis, product and system architecture and design, system development deployment, customization, and testing, technical support, email migration, and other IT services. GSS has been directly responsible for some of the largest global systems and solutions and counts as customers many of the largest companies in the world.

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©1995-2005 by Global System Services Corporation (GSS). Portions of this material are copyright ©1995-1999 by Ron Herardian