Token Ring, followed by serial networking and how to tunnel SNA traffic using Cisco routers.
This is followed by a discussion of protocol translation SDLLC, where serial SDLC traffic is
converted into Token Ring LLC2 traffic. The modern standard variant of that, data-link
switching (DLSw), is discussed, along with IBM-centric networking, or APPN (Advanced
Peer-to-Peer Networking) and the CIP processor for the 7000 series routers.
interactive terminal-oriented applications, and centralized management. The mainframe is
often considered a corporate data repository that can support large-scale client/server
applications. Expensive communication equipment such as front-end processors is now being
replaced with Cisco routers. As more and more data centers are integrated with networks, a
mainframe can be facilitated as a high-speed file server, SNMP mail server, or even as a Web
HTTP server. So instead of having separate networks, one IBM-centric and one multiprotocol-
centric, you can combine them and give new life to the mainframe. The mainframe does have
high-speed access via ATM or Gigabyte Ethernet, and high availability.
no interaction between them. They were considered separate networks. As technology
progressed and routers became smarter, the convergence of these two protocols was inevitable.
When Frame Relay became widely known about 1994, the two environments became closer
than ever before. Cisco seized this opportunity to develop software for its routers that could
handle this explosive arena. The routers and mainframes can now process more information
than ever before, and mainframes even have other uses never considered in the early days of
SNA. For example, using the mainframe as a Web server has its advantages. It allows for
migrating from legacy applications to modern-day applications.
heavily in developing a router product that could help alleviate the need for the amount of IBM
hardware a company would support by replacing the IBM equipment with Cisco routers.
routing-like function between different SNA domains, as illustrated in Figure 13-2. There were