Comparison between SNA & TCP/IP
TCP/IP versus SNA-- Part of
the History!!
TCP/IP and SNA were designed from
diametrically opposite standpoints: SNA once was a centrally managed architecture
with predefined static routing aimed at high bandwidth utilization and optimal
response time, whereas TCP/IP is a decentralized network with dynamic routing
aimed at easier connectivity.
Although the number of TCP/IP
installations is growing at an exponential rate (almost any PC-based communications
package includes the IP stack), not too many of 50,000+ SNA installations migrated
their mission-critical applications to IP.
The developers and users realized
that, unfortunately, the bandwidth of the WAN is not sufficient for LAN-based protocols.
Most of the LAN protocols (AppleTalk, network basic input/output systems [NetBIOS],
internetwork packet exchange [IPX]) are too chatty and may cause so-called
broadcast storms.
The next natural step was to
utilize the least expensive and most available protocol for WAN communications. However,
there was no magic with TCP/IP either:
So, Why didn't SNA really take off
like TCP/IP did?
A vast majority of SNA shops are
reluctant to convert their SNA backbones to TCP/IP, protecting performance of mission-critical
applications.
Many vendors realized the
importance of consolidation of the network infrastructure and the potential savings and
developed products allowing utilization of non-SNA networks for SNA traffic.
Some solutions provide SNA based
gateways and routers to allow utilization of SNA backbone for non-SNA traffic. This
approach permits capitalization on investments that many corporations have already made in
their SNA backbones.
It also grants the users a better
utilized and more cost-effective SNA network, supporting many new applications.
TCP/IP is actually two protocols
sandwiched one over other. IP deals exclusively with the routers and is primarily
concerned with the speed of delivery rather than reliability. To combat this problem of
unreliability, TCP was developed.
The TCP/IP protocols were developed
with public funding and are in the public domain. This was probably the sole reason for
its popularity!!
The TCP/IP protocol suite is a set
of network standards originally developed for the Advanced Research Projects Agency
(ARPA), of the US Department of Defense. This development led to the creation of
the ARPANET which, in turn, led to the system of national and international networks known
as the Internet.
The formal network standards for
the TCP/IP protocol suite are available as a set of documents known as Request for
Comments (RFCs). The RFCs contain a wealth of material, and some RFCs are written
specifically to provide tutorial information on the TCP/IP protocol suite.
Some sites from where you can
download the RFC's
RFC
Index search at <http://www.nexor.com/public/rfc/index/rfc.html>
Hard Copies of the RFC's can be
obtained from
References:
I have listed some books, which I have found very useful and interesting.
Author & Publisher |
Title |
|
Douglas E. Comer [Prentice Hall], 2nd ed. | Internetworking with TCP/IP: Vol.1 [Principles, Protocols and Architecture] | |
Charles L. Hedrick [ftp://cs.rutgers.edu] Download File: = tcp-ip-intro.doc (or) tcp-ip-intro.ps | Introduction to the Internet Protocols |
Maintained by Mohan Atreya , Last update April 8, 1999 First created on November 18, 1998 |