MICROSOFT NT ENTERPRISE DESIGN
Microsoft NT Network Protocols The most common
protocols used in Microsoft NT networks are NetBEUI, Novell IPX/SPX,
and TCP/IP protocol suites. Deciding which of these protocols to
implement in an enterprise environment depends on:
- Routability of the protocol - How well the protocol can be
routed across a WAN
- Performance and scalability - How well will the protocol adapt
to network growth
- Interoperability - How well will the protocol provide
connectivity to different operating systems
- Implementation - What requirements are needed in setting up
and maintaining the protocol
A global or nationwide
enterprise network consists of a WAN (Wide Area Network) made up of
routers, bridges, and gateways. Since the NetBEUI protocol supports
only local area or bridged networks, it is safe to assume that this
suite would not be appropriate in a "routed" NT enterp rise
environment. A comparison of Novell's IPX/SPX and TCP/IP protocol
suites may assist in determining which will work best in an NT
enterprise.
Routability
|
Novell IPX/SPX
Routing of network layer IPX is
available on most router hardware. Server connectivity via
SAPs (Service Advertisement Protocol) can flood an enterprise
network with broadcast packets. SAP filtering of unnecessary
advertisements should be enabled on the routers.
|
Microsoft TCP/IP
Routing of IP protocols is most
widely supported in enterprise routers. Technology based on
many years of implementation on the Internet.
|
Performance and Scalability
|
Novell IPX/SPX
Due to SAP broadcasting, the more
servers that advertise on the enterprise network, the more
bandwidth is needed to support growth in the network. However,
once a connection in made, IPX/SPX can be very reliable.
|
Microsoft TCP/IP
TCP/IP protocols work efficiently
across a WAN using packet windows where many packets can be
sent, then a single acknowledgment packet can confirm all the
packets in the entire window.
|
Interoperability
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Novell IPX/SPX
In addition to NT server
connectivity, IPX can also be used to connect to Novell
NetWare file and print servers. Other uses include NetWare SAA
Server IPX to SNA gateway connection to IBM mainframes.
|
Microsoft TCP/IP
TCP/IP protocols can be used to
connect to Microsoft NT, Microsoft LAN Manager, IBM LAN
Server, Novell NetWare, UNIX, the Internet World Wide Web, and
IBM 3172 gateway for IBM mainframes.
|
Implementation
|
Novell IPX/SPX
The Novell IPX/SPX protocol is
simple to implement. The IPX network address is generated
automatically by combining the NetWare NetWare ID number and
the Media Access Control (M AC) layer address burned into the
network interface card (NIC). This easily provides unique
network addresses for every system.
|
Microsoft TCP/IP
Implementing TCP/IP requires the
assignment of IP network addresses, which if not handled
correctly can result in duplicate IP addresses. Dynamic Host
Configuration Protocol (DHCP) can be used to automatically
assign and manage IP addressing. Windows Internet Naming
Service (WINS) can be used in resolving Microsoft NetBIOS
names to IP addresses. This is analogous to UNIX DNS host name
address resolution.
| Based on the
comparison of NetBEUI, Novell IPX/SPX, and Microsoft TCP/IP protocol
suites, we recommended implementing the Microsoft TCP/IP suite as
the protocol of choice for a Microsoft NT Enterprise network. To
understand some of the issues concerning implementing the Microsoft
TCP/IP suite in and NT Enterprise network DHCP, WINS, Network
Browsing, and RAS requires additional discussion.
Dynamic
Host Configuration Protocol (DHCP) is a service that can be provided
by an NT server and is similar to UNIX Bootp where the IP addresses
and other TCP/IP configuration parameters are automatically
assigned. In fact, the Bootp Helper (UDP packets #67 and #68) may
still be used to forward IP address requests through a router. It is
recommended that this only be used in a campus environment and that
each site in a wide area network should use its own DHCP server.
Watching for duplicate IP addresses is still critical where some
systems may be statically configured. In addition, it is best not to
use more than one DHCP server per subnet to avoid the possibility of
overlapping shared pools of IP addresses where a duplicate may be
assigned.
Windows Internet Naming Service (WINS) is a
service which can be provided by an NT server to dynamically
register NetBIOS names and resolve the names to IP addresses. WINS
is analogous to UNIX DNS (Domain Name Service) but instead of having
to e nter the host names and IP addresses manually, WINS will
automatically register the NetBIOS name and associated IP address.
Push-pulls (or replication of the WINS database) can be setup
between multiple WINS servers in an enterprise. These push-pull
connections may become daisy-chained or meshed as the number of WINS
servers are installed on the network. The solution for utilizing
WINS in an enterprise is to build a "Hub and Spokes" network. By
using a single hub WINS server and push-pulling the enterprise
database across a single link to each spoke WINS server, the chance
of data corruption is minimized.
Network Browsing can be used in MS Windows 95 Network
Neighborhood and Microsoft NT File Manager and can sometimes be
difficult to manage in an NT Enterprise network. Browsing on a
network segment is only as good as the elected browser system on the
segment. If a Microsoft NT server wins the "behind the scenes"
browser election, but is not configured correctly, others who wish
to browse on that segment may be sorely disappointed. This may be
one of the drawbacks of using a product such as Microsoft NT which
is easy for any user to purchase and install! Browsing, however,
does not necessarily affect network connectivity. That is, just
because and user can not "see" a server in his browser list, such as
Network Neighborhood, he may still be able perform a network
connection through "Map a Network Drive" or "Net Use" commands in a
login script. In an Enterprise network it is important to realize
that the browser is limited to a 64kB database, which translates to
2,000 to 3,000 entries. Because of this we recommend turning off
Microsoft Windows 95 File and Print Services on user workstations
across the enterprise unless absolutely necessary.
Remote
Access Server (RAS) is an NT service for providing a dial-up "rem
ote node" connectivity to the NT Enterprise network. As opposed to
remote control which takes over control of a host system, RAS can
act as a TCP/IP router and provide an actual network LAN connection
to the remote workstation. RAS can either use DHCP to assign IP
addresses to remote user or maintain a separate pool of addresses
reserved only for RAS users. RAS uses standard COM ports with analog
modems and can be configured to utilize a multi-port expansion board
to provide a significant modem pool.
Remember that the
enterprise domain controllers, DHCP, and WINS servers will have to
support network connectivity throughout a wide area network. It is
therefore best to locate these critical servers as close as possible
to segments directly off backbone routers. This should provide for
better performance during user logon authentication and network
server NetBIOS name resolutions.
Traffic Profile
Domain Controllers, WINS servers, and Browsers all
communicate amongst their peers. Here is the default communications
profile of these systems.
Domain Controllers
Accounts Database: Default synchronization interval is 5
minutes Login Scripts, Profiles: Default is once changes
stabilize(2min)
WINS Registration/Renewal:
Default is 4 days Push/Pull: During System initialization, at a
specific time or at Replication interval
Browsers
Registration/Renewal: Default is every 12 minutes
Browser Broadcasts: Every 15 minutes
Next
Updated August 15, 1996
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