Specifications

Chapter 12 Configuring Other Routing Protocols
IBM SNA
12-8
Catalyst 4224 Access Gateway Switch Software Configuration Guide
OL-2031-02
Phase Three: IP Client
In the third phase of SNA-to-IP integration, organizations eliminated the dual
protocol stacks at end-user PCs by implementing emulation software that
supports TCP/IP. The same rich functionality that end users relied on in their
emulation software remains the same, only it now runs over a TCP/IP stack.
Cisco Transaction Connection (CTRC) provides TCP/IP end-users and servers
with direct access to Customer Information Control System (CICS) and IBM DB2
databases. Organizations achieve protocol independence between end-users and
hosts, enabling applications to communicate directly to DB2 or CICS without
upgrades.
TN3270(E), TN5250, Distributed Relational Database Architecture (DRDA) and
Inter-System Communications (ISC) protocol are widely implemented and
widely accepted standards for achieving TCP/IP-based access to mainframes and
AS/400s. TN3270 Server technology on the router provides support for the
TN3270(E) clients. CTRC on the router supports access to IBM DB2 databases
from ODBC and JDBC drivers. CTRC also supports access to transaction
programs managed by IBM’s CICS. In addition to eliminating a second protocol
from each desktop, organizations reap the following benefits by implementing
low-cost, standards-based solutions such as TN3270(E), TN5250, and CTRC:
• Availability of high-performance servers. Very high-capacity and
high-performance gateway servers are available that offload the protocol
processing of TN3270(E) or TN5250 from the mainframe or midrange host.
These servers replace the low-capacity PC gateways that are based on
proprietary gateway protocols.
• Integration with corporate intranet. Because the desktop is based upon
TCP/IP, all the advances taking place in corporate intranets can be brought to
mainframe and midrange connections. For example, virtual private networks
(VPNs) can be created for secure remote host access. Encryption and
authentication can become a new level of security for host access.
• Access from a browser. A whole new market, the Web-to-host market, is
emerging that allows end users to access host systems using the browser as
the standard interface. This setup brings enormous benefits by reducing the
software distribution and administration chores for emulation software and
this sets the stage for a new, browser-style interface to older applications.
Organizations can look to these mission-critical applications to extend new
services to their customers, as in the case of home banking, citizen access to
government records, and insurance company applications.