Networking for today ... and tomorrow
Today, there's much talk about information highways and
Asynchronous Transfer Mode (ATM). Just as the Internet
revolutionized world-wide communications, ATM brings new meaning
to high-speed networking.
ATM promises seamless, end-to-end communications for high-speed,
multimedia networks. And ATM is not only for wide area or public
networks. In fact, ATM technology is coming faster to the campus.
Vendors of workstations and campus LAN products are offering more
and more products based on ATM to open up to new bandwidth
capacity and enable new applications.
Today, there's a lot of focus on campus networks. You're faced
with issues concerning bandwidth, backbone speed and capacity,
and complex topologies. Yet you also need to maintain a
client/server environment, ensure enough bandwidth for your
applications, and lower your cost of ownership.
Many LAN operators are increasing segmentation of their LANs
because of increasing bandwidth demand from end users and
overload on access to servers. And, in many places, they are
experimenting with LAN switching techniques. Internetworking this
large number of segments often creates structural problems and
endangers network reliability. In fact, for many people, shared
media just isn't enough anymore. Many are looking toward LAN
switching and ATM as a solution.
Why ATM? First, ATM is a dedicated, full-duplex switched
technology the ultimate in LAN switching. It adjusts the
bandwidth to whatever your application needs are. ATM provides
microsegmentation and switching because a single physical
connection can support any number of sessions. ATM is also
scalable. The speed depends only on the relationship between an
adapter and a port on the switch. ATM can scale up to 1.2
gigabits or more of bandwidth, depending on your infrastructure
needs.
Because of its inherent isochronous capabilities to handle
delay-sensitive traffic, ATM opens the door to the networking of
new applications using multimedia, mixing audio, video, and data.
These applications need higher bandwidth and faster transmission
speeds and require tight synchronization between session
partners. With ATM, bandwidth on demand is available by design.
And it's guaranteed for the duration of the call. Because ATM can
be implemented end-to-end, there's no need for protocol stacking
and conversion.
ATM from IBM is the best. Our strategy is aimed at providing ATM
capabilities to the end user. So our product line encompasses all
aspects of ATM - device interfaces, backbone accesses, ATM
switching hubs, and LAN and WAN internetworking - while
addressing network migration and administration as well.
ATM is a transport protocol. Simply put, it's a way of
transmitting data from one place to another. But ATM gives you
more than a transmission medium. It:
- Supports both private and public networks
- Uses the same technology for local and wide area networks
- Transports voice, video, and data traffic on a common circuit
- Delivers bandwidth on demand
- Offers a simplified networking structure
ATM is a switching technology that combines the reliability of
circuit switching with the efficiency of packet switching, giving
you the best way to deliver all types of data. Through simplified
packet-switching techniques, ATM segments packets into 53-byte
cells. The packets are switched onto paths operating at up to
gigabit-per-second transmission speeds. With IBM's ATM solutions,
all of the switching is done with hardware, minimizing overhead
inefficiencies. This technology can be used for both campus LANs
and wide area networks.
IBM's ATM campus strategy is aimed at providing this new facility
to desktop end users. With this goal in mind, our approach is
faced with these challenges:
- The most prevailing LAN application structure corresponds to the
client/server model. Users need ATM interfaces adapted in terms
of price, performance, and application support to the devices
that they will be used on.
- Network managers need a simplified network structure with the
capability to reassign resources to create a logical grouping or
membership (virtual LAN), independent of the physical location
of the resources.
- ATM technology must enable new applications that require a
guaranteed quality of service, including the synchronization of
transfer rates. -IBM products and system solutions must map to
the various standards recommendations, allowing you to mix and
match our products with other vendor equipment. But we're not
waiting for standards to happen - we're actively working to
promote solutions that give the best return on your investment
and protect your installed base.
So, our strategy addresses all aspects of the campus environment,
including access to the WAN using private facilities or public
services. The directions of our ATM campus strategy are
described in the following sections.
This requires a physical interface using current cabling
infrastructure, like shielded twisted-pair (STP) or
unshielded-twisted pair (UTP-3), at a cost competitive with
current LANs. The 25 Mbps interfaces address this problem. IBM is
part of a consortium of over 25 vendors promoting this interface
at the ATM Forum.
Bringing ATM to the desktop also requires interoperation between
users of ATM and users of current LAN technologies. We developed
a LAN bridge and invested in the definition of the LAN emulation
concept to address the physical and logical interoperation
problems.
ATM campus backbone
We provide a set of ATM switching hubs, with internodal links of
scalable bandwidth plus the network operating system, that
dynamically updates the topology, discovers the network routes,
and enables users to establish connections between themselves.
Our ATM network operating system incorporates facilities to
allocate and control bandwidth at any instant. The interfaces
with the end-user devices or vendor switches conform to the
various recommendations of the ATM Forum.
ATM network control functions represent the overall system
control and services to ensure communications within the network.
Usually, the control system is within a hub, or other
concentration device, connecting the devices in the network.
When a workstation initiates a call, it indicates the destination
station and the quality of service required for the connection.
Quality-of-service requirements include the amount of bandwidth
required and the maximum delay acceptable for this application.
The connecting ATM switching hub that receives the call
identifies the best route with the required bandwidth between the
two stations, using a path selection algorithm. This algorithm
also updates all of the topology tables in the various ATM
switching hubs and forwards that information across the route.
Although it seems like a lot of information is being gathered and
forwarded, the process actually takes place quickly because the
information is carried at the speed of ATM across the network.
The routing and addressing information is stored in buffers, or
caches, contained in ATM switching hubs, and is not recomputed
unless it's been replaced by new data.
The behavior of the network is very sophisticated, but it
requires very little predefinition by the network administrator.
The hubs exchange the topology information and the available
bandwidth over the various backbone links. When a node is added
to the backbone, you only need to give it a unique identifier and
enable the internodal links. From that point on, the control
system takes over. It informs its neighbors of its existence and
of the bandwidth links that were just added. Each node updates
its topology map and the new structure is automatically
propagated over the backbone.
For applications developed in native ATM mode, the control system
uses a reserved bandwidth method in which the network guarantees
the bandwidth requested. The bandwidth is determined at call
setup. If the required bandwidth is available all along the
route, the call is accepted and the connection gets absolute
priority. For this kind of connection, the network performs
policing, checking that the source does not exceed its contract
and realigning the received cells according to the traffic rate
and cell-delay variation constraints.
For LAN applications, which aren't designed to request specific
bandwidth, the network uses nonreserved bandwidth, also called
the available bit rate. In this mode of operations, the control
system performs a best-effort service to transport data. If the
network detects congestion, it sends back-pressure cells to the
source of the traffic, whether it's a device, bridge, or router.
When the adapter receives these back-pressure cells, it slows
down or stops the transmitting application for a specified amount
of time. This is built-in so you won't lose any information
across the network because of congestion. In addition, to
accommodate the bursty nature of this LAN traffic, the ATM
switching hub is equipped with large cell buffering on both
incoming and outgoing directions.
These two modes of operation work independent of each other, but
the reserved bandwidth has absolute priority. However, the
nonreserved traffic uses, at any time, all the unused remaining
bandwidth, thus providing optimal usage of the link capacity.
IBM's implementation of multicast services uses specific
capabilities of our very large scale integration (VLSI)
Switch-on-a-Chip switching architecture. This eliminates the
duplication of ATM cells, and any corresponding overhead, and
improves network performance.
Our ATM management system can be used by your current network
administration staff with minimal training. The system is
automated for every clerical task and eliminates the need for
system generation of resources and routes. Its graphical user
interface simplifies the tasks of network administrators,
allowing them to navigate among all the components of the complex
campus network, whether ATM or traditional LANs. The management
system is implemented on SNMP industry standards and uses the ATM
Forum and Internet Engineering Task Force (IETF) management
information bases (MIBs).
You can implement ATM as a replacement of FDDI for your backbone
or as a follow-on LAN for token-ring and Ethernet networks based
on shared media. It also gives you a structure for multimedia
applications. But going from traditional LANs to ATM requires a
hub control point and a set of system functions that support your
current LAN operating system. To help you handle this
requirement, IBM offers three modes of operation:
- Native ATM, to support all the capabilities of the new
technology. It takes special advantage of guaranteed bandwidth
and synchronous transmission.
- IP over ATM, as recommended by RFC 1577, to support TCP/IP
networking.
- LAN emulation, to support all other current LAN
operations, like NetBIOS, SNA, or other layer 2 or layer 3
protocols.
LAN emulation is a concept and a service. Our implementation of
LAN emulation uses an address resolution server that works with
client interfaces situated in adapters for workstations or
bridges. With LAN emulation, your token-ring and Ethernet LANs
interact seamlessly with another ATM LAN or other directly
attached LANs. LAN emulation emulates the operations of existing
LANs, thus making ATM transparent to the existing applications on
end-user workstations. So, you can smoothly migrate from your
existing LANs to ATM, and your end users get the benefits of
higher bandwidth without changing their applications and without
middleware.
The LAN Emulation Servers provide multicast services and can
resolve broadcast demands from end users. These servers recognize
various end users that are connected or defined in their domains.
LAN emulation is facilitated by IBM s implementation of multicast
services. With this LAN emulation service, virtual LANs become a
reality.
A virtual LAN is a logical grouping of workstations or clients
and servers, regardless of where they are physically located in
the network. Through virtual LANs, you can provide bandwidth
where it s required, independent of where the device is plugged
in. And with LAN Emulation Servers, you can simply group stations
in any logical way, just by providing the LAN Emulation Server
with the necessary station addressing and registration
information.
As part of IBM's strategy for ATM, you ll find campus products to
enable ATM backbones, switch-based ATM workgroups, and
coexistence with existing devices and applications. For
workstation adapters and end-user connectivity, we re focusing on
using existing industry interfaces hardware and software (for
example, ISA bus, NDIS, or ODI) and existing wiring, including
voice-grade and STP or UTP-3 wiring. This entry-level ATM
offering can save you money by reusing what you already have
installed.
The TURBOWAYS* 100 ATM Adapter for RISC System/6000* systems can
be installed in a powerful IBM RISC processor and is supported by
AIX* Version 4. It implements a full on-board processor and
interfaces to a Micro Channel* (MCA) bus. The TURBOWAYS 100 ATM
Adapter can support over 97 percent of sustained throughput.
You can get the TURBOWAYS 25 ATM Adapter for desktop workstations
and the TURBOWAYS 100 ATM Adapter for high-speed workstations or
servers. Our TURBOWAYS adapters come with LAN emulation software
to support traffic from current LAN applications. The IBM 8282
TURBOWAYS ATM Concentrator lets you connect up to twelve 25 Mbps
ATM workstations to a single, high-speed ATM switch port. When
used in conjunction with TURBOWAYS 25 ATM Adapters, it provides a
cost-effective means of delivering ATM to the desktop. The concentrator
also contains a control program and an SNMP agent to manage it
from an application running on NetView* for AIX.
To connect existing LANs to the ATM network, IBM offers the IBM
8281 ATM LAN Bridge. It can perform source route bridging between
two or four token-ring LANs and 1 emulated token ring (ie ATM;
lan emulation) or it can perform transparent bridging between 2
or 4 Ethernet LANs and 1 emulated Ethernet (ie ATM; lan emulation).
The 8281 ATM LAN Bridge also contains an SNMP agent for
remote management and supports LAN emulation between
the ATM network and the attached existing LANs.
For access to your mainframe, you can use a 100 Mbps ATM adapter
in the IBM 3172 Interconnect Controller Model 3. You can also
have direct attachment to the IBM Scalable POWERparallel System
with a 100 Mbps ATM adapter.
The heart of the campus backbone is a high-speed ATM switching
hub. IBM's ATM switch is the 8260 Multiprotocol Intelligent
Switching Hub, part of the Nways family of products. The 8260 Hub
includes the Switch-on-a-Chip VLSI component and ATM
concentration modules. With Switch-on-a-Chip, you ll get a
scalable, nonblocking switch fabric capable of delivering high
port speeds and automatic contention resolution. This powerful
ATM switch supports the direct attachment of your servers,
high-speed workstations, concentrators, and LAN bridges. It also
connects to other switches, giving you the required scalability
for any given campus network. The 8260 Hub supports subnetworking
as well as multinetworking to satisfy the requirements of large
or complex ATM networks.
The 8260 Hub comes with a control program that handles the
topology, computes the routes, and builds the VPI/VCI
label-swapping tables that control ATM switching. It also
performs processing for traffic management and permanent virtual
circuits. The 8260 Hub can download code and manage configuration
services. The control program contains an SNMP agent.
In the future, the 8260 Hub will have modules for the attachment
of 155 Mbps ATM interfaces to either servers or other hubs and 25
Mbps concentration modules. These modules will support different
physical connectors (fiber and copper). We plan to integrate the
Nways ATM LAN Bridge and the LAN Emulation Server to take
advantage of the 8260 fault-tolerant platform. We ll also provide
modules to connect the 8260 Hub to a wide area network.
The 8260 Hub supports all current LAN attachments token ring,
Ethernet, and FDDI. Because we want to make ATM an additional or
alternate LAN technology, transforming the 8260 Hub into an ATM
switching hub is done simply by adding the 8260 ATM Backplane and
the 8260 ATM Switching/Control Point Module.
For network management within your campus LAN, you can count on
IBM NetView for AIX using the industry-standard SNMP protocol. We
offer ATM Campus Manager for AIX, giving you a complete solution
for managing the 8260 Hub.
ATM Campus Manager for AIX offers graphical screens and resizable
network views with easy-to-identify, color-coded icons. Its
auto-topology function is fully integrated with NetView for AIX,
making it possible to navigate from the NetView for AIX IP map to
the ATM topology map using the protocol switching function. From
the network management station, you can:
- Manage ATM connections (PVCs and SVCs)
- Configure the 8260 ATM switch
- Monitor and modify performance and the parameters of the network
There are many reasons to choose ATM from IBM. We focus on an
end-to-end, total system solution for campus networks. So, you
get products that are designed to work together. You also get
state-of-the-art technologies and solutions that are available
today.
IBM's experience in high-speed networking gives us a solid
foundation for developing leading-edge network-control and
optimization features. These features comply with industry
standards and go beyond them in providing functional value. We
focus on designing cost-effective ATM components by reusing
existing wiring and applications and by economically controlling
bandwidth.
We are delivering products on a schedule to meet your needs today
and tomorrow. IBM is a principal member of the ATM Forum and most
international standards organizations. We will comply with and
implement standards recommendations as they are developed. Our
product line ranges from workstation adapters to hubs to network
management applications, giving you flexibility to implement
whatever you need to manage your network successfully. We also
offer services and education for ATM. And we ll help you make the
move to ATM a smooth one, at your own pace.
You won't find a better total system solution built around ATM
today than at IBM. With solutions that provide coexistence and
migration options and economic and functional values, IBM is
delivering what you need. At IBM, we re listening to you when it
comes to your networking needs.
For more information about ATM from IBM, look for these
brochures:
- IBM ATM Strategy, G325-3509
- IBM Networking BroadBand Services, G325-3511
- IBM switch-on-a-Chip, G325-3512
- IBM ATM Network Management Strategy, G325-3513
You can also order videotapes on ATM. In the U.S. and Canada,
call 1-800-IBM-TEACH (1-800-426-8322), extension FTN. Or, contact
your IBM representative. The tapes currently include:
- IBM's ATM Strategy, with Dr. Daniel Abensour
- ATM Switch Architecture, with Dr. Ton Engbersen
- Networking BroadBand Services, with Dr. Jerry Marin
- IBM ATM Campus Solutions, with Henri Sourbes
- ATM Network Management, with Roger Kosak
- Nways BroadBand Network Switch, with Gerald Lebizay
(c)International Business Machines Corporation 1995.
All Rights Reserved.
IBM United States
Department E23
PO Box 12195
Research Triangle Park, NC 27709
* Trademark of International Business Machines Corporation.
IBM does not determine whether every mark used by another is
considered a trademark. The absence of a trademark identifier
is not a representation that no third party claims trademark
rights in a particular mark.
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