ch05.htm

this describes managing multivendor networks

other networking protocols.
<H3><A NAME="Heading6"></A><FONT COLOR="#000077">Peer-to-Peer Relationships</FONT></H3>
<P>Peer-to-peer processing is a critical element within Sun's concept of workgroup
computing, and it significantly influences Sun's approach to networking. In Sun's
world, people with similar information requirements must be able to share this information
with one another to reduce duplication and increase efficiency. Sun provides two
critical functions to establish and maintain peer-to-peer relationships: Network
File System (NFS) and RPCs.</P>
<P>NFS provides common access to shared information. Multiple programs and users
can access the same set of information, such as files and records, as peers via NFS.
Because NFS can oversee multiple systems accessing the same information, NFS can
be a focal point for this sharing or exchange of data. A key factor in this technology
is NFS's capability to perform record-level and file-level locking to prevent the
simultaneous update of the same information (see Figure 5.2).</P>
<P><A HREF="javascript:if(confirm('http://docs.rinet.ru:8080/MuNet/ch05/05fig02.gif  \n\nThis file was not retrieved by Teleport Pro, because it was redirected to an invalid location.  You should report this problem to the site\'s webmaster.  \n\nDo you want to open it from the server?'))window.location='http://docs.rinet.ru:8080/MuNet/ch05/05fig02.gif'" tppabs="http://docs.rinet.ru:8080/MuNet/ch05/05fig02.gif"><B>FIG. 5.2</B></A> <I>Peer-to-Peer Communications via NFS</I></P>
<P>RPCs are used for customized program-to-program communications. From another perspective,
programs on different systems can establish peer-to-peer communications with one
another via Sun's RPC architecture. After the communications link is established,
the two (or more) programs can freely exchange information with one another, regardless
of their respective locations in the network (see Figure 5.3).</P>
<P><A HREF="javascript:if(confirm('http://docs.rinet.ru:8080/MuNet/ch05/05fig03.gif  \n\nThis file was not retrieved by Teleport Pro, because it was redirected to an invalid location.  You should report this problem to the site\'s webmaster.  \n\nDo you want to open it from the server?'))window.location='http://docs.rinet.ru:8080/MuNet/ch05/05fig03.gif'" tppabs="http://docs.rinet.ru:8080/MuNet/ch05/05fig03.gif"><B>FIG. 5.3</B></A> <I>Peer-to-Peer Communications via RPC</I></P>
<P>Furthermore, these functions are not mutually exclusive. Combined RPC and NFS
solutions can, for example, be implemented to share data in localized work groups
via NFS, while RPC functions are used to distribute a subset of the local information
to a wider audience within the total network.</P>
<P>Thus, implementing NFS and RPC on a wide variety of systems produced by different
manufacturers is an attractive possibility. NFS and RPC can be used in a multivendor
environment to create peer-to-peer relationships between systems and programs that
previously could not recognize one another or exchange information.
<H3><A NAME="Heading7"></A><FONT COLOR="#000077">PC Integration Strategy</FONT></H3>
<P>Sun's underlying approach to integrating PCs with its technology focuses on PCs
operating on the same LAN as the Sun equipment or networking products. Within that
LAN, Sun concentrates on enabling the PCs to access standard ONC/NFS services. In
the case of file services, this means that the PCs can access a non-PC NFS server.</P>
<P>Sun's main product in the PC arena is PC-NFS, a PC-resident software package that
permits DOS and Windows users to share data and resources with UNIX systems, minicomputers,
and mainframes running TCP/IP and ONC/NFS. PC-NFS works with a PC Ethernet card and
provides basic connectivity to the network (via TCP/IP) and to NFS servers. The three
basic PC-NFS functions (see Figure 5.4) are:

<UL>
	<LI><I>NFS Client.</I> This function within PC-NFS handles the interface between
	MS-DOS and the NFS server. In this role, the NFS Client performs the necessary network
	activity (in concert with the network hardware) to communicate with the NFS server.
	Because the NFS file structure (native UNIX) is foreign to MS-DOS, the NFS Client
	function also handles the mapping of the NFS names into MS-DOS names. And finally,
	the NFS Client works with both MS-DOS and NFS to support and maintain networkwide
	record and file locks.
</UL>

<P><A HREF="javascript:if(confirm('http://docs.rinet.ru:8080/MuNet/ch05/05fig04.gif  \n\nThis file was not retrieved by Teleport Pro, because it was redirected to an invalid location.  You should report this problem to the site\'s webmaster.  \n\nDo you want to open it from the server?'))window.location='http://docs.rinet.ru:8080/MuNet/ch05/05fig04.gif'" tppabs="http://docs.rinet.ru:8080/MuNet/ch05/05fig04.gif"><B>FIG. 5.4</B></A> <I>Connectivity via Sun's PC-NFS</I>

<UL>
	<LI><I>VT100 emulation.</I> Because the lower layers of PC-NFS depend on TCP/IP to
	handle the networking services, the product also includes VT100 emulation for TELNET
	access. This enables the PC to act as a terminal to access other systems in the NFS
	and/or TCP/IP network.<BR>
	<BR>
	
	<LI><I>File Transfer Protocol (FTP).</I> Most implementations of TCP/IP include FTP,
	which transfers files from one system to another. PC-NFS includes FTP to provide
	a high degree of functional compatibility with other TCP/IP systems in the network.
	Whereas the NFS Client can provide online access for a user or application to an
	NFS file, FTP makes a copy of a file on another system.
</UL>

<P>In addition to the main PC-NFS package, Sun offers the following add-ons:

<UL>
	<LI><I>SolarNet PC Management.</I> This software gives PC users access to the UNIX
	operating system, and permits administrators to manage networked PC systems. The
	system enables users to share enterprisewide data across multiple, heterogeneous
	servers through TCP/IP connectivity and NFS integration. PC clients can become equal
	members on the LAN and all resources will appear to the PC as if they were local.<BR>
	<BR>
	
	<LI><I>PC-NFS LifeLine Mail.</I> This package supports the TCP/IP standard Simple
	Mail Transfer Protocol (SMTP) and the Berkeley UNIX's Post Office Protocol (POP)
	to enable the PC to participate in electronic mail.<BR>
	<BR>
	
	<LI><I>PC-NFS LifeLine Backup.</I> Because NFS servers tend to have a large disk
	capacity, the Backup package enables a PC to use an NFS server as a backup device
	for local and network information. In addition to backing up to the NFS server, PC-NFS
	LifeLine Backup also supports networkwide backup to a tape drive attached to an NFS
	server.<BR>
	<BR>
	
	<LI><I>PC-NFS Programmer's Toolkit.</I> This product includes a set of Sun's XDR
	and RPC library routines that programmers can use to establish communications between
	PC-resident programs and other programs operating in the Sun RPC/XDR. These routines
	enable programs operating on PCs to establish peer relationships with programs operating
	anywhere on the network.
</UL>

<P>Another event that fortified Sun's PC integration strategy was a joint announcement
in late 1989 by Sun, Novell, and Netwise, in which they revealed a plan to support
Sun's RPC and XDR in Novell networks. Under this plan, Sun provided the ONC/NFS standard,
Novell's NetWare was enhanced to support RPC, and Netwise revised its product, RPC
TOOL, to include support for both Sun and OSI RPC formats.
<H3><A NAME="Heading8"></A><FONT COLOR="#000077">Office Automation</FONT></H3>
<P>To date, Sun has no strong offering of its own in the area of office automation.
Instead, it relies on TCP/IP's SMTP, Berkeley's POP, and third-party products to
provide stand-alone and integrated multivendor office automation solutions. This
approach is really no different from their approach to any other general application.</P>
<P>Sun bundles the Ultra Pack with its Ultra workstations. Ultra Pack is a set of
applications and tools, including several collaborative applications. Sun's ShowMe
shared whiteboard application is included for collaboration. The Ultra Pack also
includes the Netscape Navigator World Wide Web navigator, Sun's own Hot Java browser,
several multimedia tools, an MPEG II player, and a music player.</P>
<P>The SunSoft WorkShop includes tools that permit developers to take advantage of
the UltraSPARC instruction set. WorkShop includes the SunSoft Visual WorkShop for
C++, SunSoft WorkShop for C, SunSoft Performance WorkShop for Fortran 90, SunSoft
WorkShop for FORTRAN 77, and SunSoft WorkShop for Ada. These new compilers offer
a significant performance improvement and require minimal code modification. The
SunSoft Performance Library is an optimized implementation of common numerical algorithm
libraries used for applications such as structural analysis, computational fluid
dynamics, and simulation.
<H2><A NAME="Heading9"></A><FONT COLOR="#000077">Network Architecture</FONT></H2>
<P>At the simplest level, Sun's foundation for networking is based on running TCP/IP
over an Ethernet network. In doing this, Sun uses the same network topology (bus),
the same network discipline (Carrier Sense Multiple Access with Collision Detection),
and the same basic medium attachments (transceivers) that Digital Equipment uses.
In fact, Sun workstations are frequently found on the same physical LANs on which
DEC equipment resides (although this does not necessarily mean that the two types
of equipment communicate).</P>
<P>In a Sun network, then, the workstations and servers attach to a thick or thin
LAN (see Figure 5.5). TCP/IP manages communications over the 10 Mbps Ethernet. Communications
among the systems on the LAN can occur in two different fashions.</P>
<P><A HREF="javascript:if(confirm('http://docs.rinet.ru:8080/MuNet/ch05/05fig05.gif  \n\nThis file was not retrieved by Teleport Pro, because it was redirected to an invalid location.  You should report this problem to the site\'s webmaster.  \n\nDo you want to open it from the server?'))window.location='http://docs.rinet.ru:8080/MuNet/ch05/05fig05.gif'" tppabs="http://docs.rinet.ru:8080/MuNet/ch05/05fig05.gif"><B>FIG. 5.5</B></A> <I>Sample Sun Network Architecture</I></P>
<P>Because Sun's underlying network protocol is TCP/IP, the standard TCP/IP mechanisms
for system-to-system communications can be used. In Sun's environment, the two most
widely used communications are TELNET for terminal access and FTP for file transfer.</P>
<P>Sun has added its own network services above TCP/IP. These services are commonly
referred to as Open Network Computing/Network File System (ONC/NFS). They include
NFS for sharing files and records throughout the network, and RPC to enable a program
running on one system to communicate with a program running on a different system.</P>
<P>Connectivity with PCs starts with the PCs being connected to the Ethernet LAN.
Running with MS-DOS, Sun supplies PC-NFS to implement TCP/IP on the Ethernet connection
and to provide three essential services that enable the PC to participate in the
Sun network: NFS Client for access to files stored on NFS servers, VT100 to give
the PC TELNET access, and FTP for file transfers.</P>
<P>In terms of interfacing with other systems, Sun has focused on connectivity with
DEC and IBM, enabling its ONC/NFS partners to establish other connectivity options
with other systems. Sun uses a gateway approach between the Sun and IBM network environments.
Its SunLink connectivity solution for IBM equipment can connect to an IBM mainframe
system via a channel attachment, a SNA SDLC data communications connection or a non-SNA
bisynchronous data communication link. The SunLink IBM solution offers the following:

<UL>
	<LI>IBM 3270 terminal emulation to access IBM applications.<BR>
	<BR>
	
	<LI>RJE and NJE emulation to facilitate bidirectional file transfer.<BR>
	<BR>
	
	<LI>LU 6.2 support for native IBM program-to-program communications (APPC).
</UL>

<P>For DEC connectivity, Sun supplies two approaches with SunLink DNI and implements
support for DECnet. This solution provides the following:

<UL>
	<LI>VT100 emulation for access to DEC systems.<BR>
	<BR>
	
	<LI>Support for standard DECnet file transfers.<BR>
	<BR>
	
	<LI>Support for standard DECnet task-to-task communications.
</UL>

<P>Alternatively, Sun provides a solution that implements NFS (and TCP/IP) in a VAX
environment, thus enabling the DEC equipment to participate in the Sun network.</P>
<P>Other connectivity solutions are provided by the companies subscribing to the
ONC/NFS strategy. Also, because Sun implements standard TCP/IP over Ethernet, virtually
any standard Ethernet bridges can be used to tie Sun networks together over a wide
area.
<H3><A NAME="Heading10"></A><FONT COLOR="#000077">High-Speed Networking</FONT></H3>
<P>Sun offers switched Fast Ethernet and Fast/Wide SCSI 2 functionality directly
on the motherboard of the Ultra series of workstations and servers. No other workstation
vendor is currently offering Fast Ethernet directly on the motherboard. Sun's SunATM
Adapter 2.0 provides for 155 Mbps ATM networking. Sun also offers a 10/100 Mbps auto-sensing
SunFastEthernet add-on adapter and the SuNFDDI adapter for connectivity to 100 Mbps
FDDI networks.</P>