SmartSwitch 9000
9T122-24
User’s Guide
9031206-02
Notice
Notice
Cabletron Systems reserves the right to make changes in specifications and other information
contained in this document without prior notice. The reader should in all cases consult Cabletron
Systems to determine whether any such changes have been made.
The hardware, firmware, or software described in this manual is subject to change without notice.
IN NO EVENT SHALL CABLETRON SYSTEMS BE LIABLE FOR ANY INCIDENTAL, INDIRECT,
SPECIAL, OR CONSEQUENTIAL DAMAGES WHATSOEVER (INCLUDING BUT NOT LIMITED
TO LOST PROFITS) ARISING OUT OF OR RELATED TO THIS MANUAL OR THE INFORMATION
CONTAINED IN IT, EVEN IF CABLETRON SYSTEMS HAS BEEN ADVISED OF, KNOWN, OR
SHOULD HAVE KNOWN, THE POSSIBILITY OF SUCH DAMAGES.
© Copyright March 1998 by:
Cabletron Systems, Inc.
35 Industrial Way
Rochester, NH 03867-5005
All Rights Reserved
Printed in the United States of America
Order Number: 9031206-02
LANVIEW is a registered trademark, and SmartSwitch is a trademark of Cabletron Systems, Inc.
CompuServe is a registered trademark of CompuServe, Inc.
i960 microprocessor is a registered trademark of Intel Corp.
Ethernet is a trademark of Xerox Corporation.
i
Notice
FCC Notice
This device complies with Part 15 of the FCC rules. Operation is subject to the following two
conditions: (1) this device may not cause harmful interference, and (2) this device must accept any
interference received, including interference that may cause undesired operation.
NOTE: This equipment has been tested and found to comply with the limits for a Class A digital
device, pursuant to Part 15 of the FCC rules. These limits are designed to provide reasonable
protection against harmful interference when the equipment is operated in a commercial environment.
This equipment uses, generates, and can radiate radio frequency energy and if not installed in
accordance with the operator’s manual, may cause harmful interference to radio communications.
Operation of this equipment in a residential area is likely to cause interference in which case the user
will be required to correct the interference at his own expense.
WARNING: Changes or modifications made to this device which are not expressly approved by the
party responsible for compliance could void the user’s authority to operate the equipment.
VCCI Notice
This is a Class A product based on the standard of the Voluntary Control Council for Interference by
Information Technology Equipment (VCCI). If this equipment is used in a domestic environment,
radio disturbance may arise. When such trouble occurs, the user may be required to take corrective
actions.
DOC Notice
This digital apparatus does not exceed the Class A limits for radio noise emissions from digital
apparatus set out in the Radio Interference Regulations of the Canadian Department of
Communications.
Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les limites applicables
aux appareils numériques de la class A prescrites dans le Règlement sur le brouillage radioélectrique
édicté par le ministère des Communications du Canada.
ii
Notice
DECLARATION OF CONFORMITY
ADDENDUM
Application of Council Directive(s):
89/336/EEC
73/23/EEC
Manufacturer’s Name:
Manufacturer’s Address:
Cabletron Systems, Inc.
35 Industrial Way
PO Box 5005
Rochester, NH 03867
European Representative Name:
European Representative Address:
Mr. J. Solari
Cabletron Systems Limited
Nexus House, Newbury Business Park
London Road, Newbury
Berkshire RG13 2PZ, England
Conformance to Directive(s)/Product Standards:
Equipment Type/Environment:
EC Directive 89/336/EEC
EC Directive 73/23/EEC
EN 55022
EN 50082-1
EN 60950
Networking Equipment, for use in a
Commercial or Light
Industrial Environment.
We the undersigned, hereby declare, under our sole responsibility, that the equipment packaged with
this notice conforms to the above directives.
Manufacturer
Legal Representative in Europe
Mr. Ronald Fotino
____________________________________________________
Mr. J. Solari
______________________________________________________
Full Name
Full Name
Principal Compliance Engineer
____________________________________________________
Managing Director - E.M.E.A.
______________________________________________________
Title
Title
Rochester, NH, USA
____________________________________________________
Newbury, Berkshire, England
______________________________________________________
Location
Location
iii
Notice
iv
Contents
Chapter 1
Chapter 2
Introduction
Features........................................................................................................................... 1-1
Related Manuals............................................................................................................ 1-4
Getting Help .................................................................................................................. 1-4
Installation
Installing the MicroLAN Module ............................................................................... 2-1
The Reset Switch ........................................................................................................... 2-3
User-Accessible Components...................................................................................... 2-4
Setting the Module Card DIP Switch ......................................................................... 2-5
Ring Speed ..................................................................................................................... 2-6
Multi-Ring Out Capability........................................................................................... 2-7
Chapter 3
Operation
Bridging .......................................................................................................................... 3-2
Transparent Bridging............................................................................................. 3-2
Source Route Bridging .......................................................................................... 3-3
Spanning Tree Algorithm...................................................................................... 3-3
Flexible Network Bus (FNB)........................................................................................ 3-4
System Management Buses ......................................................................................... 3-4
SMB-1 Bus ............................................................................................................... 3-4
SMB-10 Bus ............................................................................................................. 3-4
System Diagnostic Controller...................................................................................... 3-5
DC/ DC Converter ........................................................................................................ 3-5
FNB Interface ................................................................................................................. 3-5
i960 Core......................................................................................................................... 3-5
Chapter 4
Chapter 5
LANVIEW LEDs
Specifications
Safety............................................................................................................................... 5-1
Service............................................................................................................................. 5-1
Physical........................................................................................................................... 5-2
Dimensions: ............................................................................................................ 5-2
Weight:..................................................................................................................... 5-2
Electrical ......................................................................................................................... 5-2
v
Contents
vi
Chapter 1
Introduction
The 9T122-24 MicroLAN™ Switch Module, shown in Figure 1-1, is a three port
Token Ring bridge and router module. This module supports either one token
ring with 24 HUB connections, or two separate Token Rings with 12 HUB
connections, and an interface to the FNB backplane.
Features
Processor
The 9T122-24 is equipped with an advanced Intel i960 microprocessor. This
microprocessor provides a platform for all management functions within a
scalable RISC-based architecture.
System Management
Interfaces to the two System Management Buses (SMB-1 and SMB-10) for
intermodule management.
Connectivity
The 9T122-24 provides 24 RJ-45 Trunk Coupling Unit (TCU) lobe connectors. The
connectors may be configured as one 24-port ring (default) or two 12-port rings.
Bridging/Routing
Bridging/ Routing between the front panel Token Ring connections and/ or to any
other module in the chassis via FNB-1 or FNB-2 of the FNB bus. The module is
capable of Transparent Bridging or Source Route Bridging. IEEE 802.1d Spanning
Tree Protocol is supported in all bridging functions. Translational bridging
between Source Routing and Transparent Frames types is also performed.
1-1
Introduction
Management Information Base (MIB) Support
The 9T122-24 module provides MIB support including:
•
•
•
•
•
IETF MIB II (RFC 1213)
IETF RMON MIB (RFC 1271 and 1513)
IETF Bridge MIBs (RFC 1493 and 1525)
IEEE 802.5 Token Ring MIB (RFC 1231)
Cabletron Enterprise MIBs
For a complete list of supported MIBs, refer to the release notes provided in the
module package.
NOTE
Ring Security
This feature prevents unauthorized stations from attaching to the ring. Using
Local or Remote Management, the module may be configured as to which MAC
addresses are allowed to operate on the ring.
Multi-Ring Out Capability
With this feature any port of the module may be configured as a ring-out port
through management software. In this configuration a stand-alone passive
concentrator (such as an IBM 8228 MAU) may be added to the ring.
Telnet
A telnet session can be set up with the module to provide access to the Local
Management screens.
LANVIEW LEDs
The 9T122-24 use LANVIEW – the Cabletron Systems built-in visual diagnostic
and status monitoring system. With LANVIEW LEDs, you can quickly identify
the device, port, and physical layer status at a glance.
Hot Swapping
The 9T122-24 can be installed or removed from the chassis while the SmartSwitch
9000 is powered up without affecting the operation of the remaining modules in
the chassis.
1-2
Introduction
Related Manuals
The manuals listed below should be used to supplement the procedures and
technical data contained in this manual.
SmartSwitch 9000 Installation Guide
SmartSwitch 9000 Operations Guide
SmartSwitch 9000 9C300-1 Environmental Module User’s Guide
SmartSwitch 9000 9C214-1 AC Power Supply User’s Guide
SmartSwitch 9000 Local Management User’s Guide
Getting Help
For additional support related to this device or document, contact the Cabletron Systems Global Call
Center:
Phone
(603) 332-9400
Internet mail
FTP
ctron.com (134.141.197.25)
anonymous
Login
Password
your email address
BBS
(603) 335-3358
Modem setting
8N1: 8 data bits, No parity, 1 stop bit
For additional information about Cabletron Systems or its products, visit the
For technical support, select Service and Support.
To send comments or suggestions concerning this document, contact the
Cabletron Systems Technical Writing Department via the following
Make sure to include the document Part Number in the email message.
Before calling the Cabletron Systems Global Call Center, have the following information ready:
•
•
•
Your Cabletron Systems service contract number
A description of the failure
A description of any action(s) already taken to resolve the problem (e.g., changing mode switches,
rebooting the unit, etc.)
•
•
•
•
•
The serial and revision numbers of all involved Cabletron Systems products in the network
A description of your network environment (layout, cable type, etc.)
Network load and frame size at the time of trouble (if known)
The device history (i.e., have you returned the device before, is this a recurring problem, etc.)
Any previous Return Material Authorization (RMA) numbers
1-4
Chapter 2
Installation
Installing the MicroLAN Module
The SmartSwitch 9000 MicroLAN Module may be installed into any of the 14 slots
that are available. To install, follow the steps below:
1. Switch off the power supplies and remove all power from the SmartSwitch
9000 chassis.
2. Remove the blank panels, covering the slots that the module is being mounted
in. All other slots must be covered, if modules are not being installed, to
ensure proper airflow and cooling.
3. Carefully remove the module from the shipping box. (Save the box and
packing materials in the event the module must be reshipped.)
4. Attach one end of the ESD wrist strap packaged with the SmartSwitch 9000
chassis to your wrist. Plug the other end into the ESD Wrist Strap Grounding
receptacle in the lower right corner of the SmartSwitch 9000 Chassis shown in
5. Remove the module from the plastic bag. Observe all precautions to prevent
damage from Electrostatic Discharge (ESD).
6. Carefully examine the module, checking for damage. If any damage exists,
DO NOT install the module. Contact Cabletron Systems Technical Support
immediately.
7. Slide the module into a slot and lock down both the top and bottom plastic
engages the backplane connectors properly. When installing the module,
ensure that both circuit cards are between the card guides, as shown in
2-1
Installation
The Reset Switch
The Reset switch is located on the front panel, under the top plastic tab as shown
in Figure 2-2. It serves two functions:
•
Pressing the reset switch twice within three seconds causes the processor (i960)
to reset.
•
Pressing and holding the switch on for three or more seconds causes the
module to shutdown. Pressing and holding again for three seconds restarts the
module.
SNMP management may be used to disable this switch to enhance module
security.
Reset Switch
SMB
CPU
Figure 2-2. The Reset Switch
2-3
Installation
User-Accessible Components
consist of an eight-position dip switch (explained in the next section), replaceable
PROMs and sockets for RAM. These will be used for future upgrades.
SMB-1 PROM
i960 Processor
Flash SIMM
Socket
DIP Switch
Boot PROM
Shared Packet
Memory SIMM
Local Program Memory
SIMM Socket
Figure 2-3. User Accessible Components
2-4
Installation
See the Cautions at the end of this table.
Table 2-1. Function of DIP Switch
Switch
8
Function
Description
When toggled, this switch clears user-entered
passwords stored in NVRAM, and restores the
default passwords. Once reset you can use the
defaults or enter new passwords.
1
Clear Password
The module uses NVRAM to store user entered
parameters such as IP addresses, device name, etc.
To reset these parameters to the factory defaults,
toggle this switch. Once reset, you can use the
defaults or enter new parameters, which are stored
in NVRAM when the module is powered down,
and remain there until the switch is toggled again.
2
7
6
Clear NVRAM
Toggling this switch after pulling the board out of
the SmartSwitch 9000, clears download information
from NVRAM and forces image files to be
downloaded from the station configured to act as
that modules’ BOOTP server.
Force BootP
Download
For Factory Use Only
For Factory Use Only
For Factory Use Only
For Factory Use Only
5
4
3
2
Reserved
Reserved
Reserved
Reserved
Off = One ring of 24 ports (factory default)
On = two rings of 12 ports each
Ring
Configuration
1
1
Caution: Do not toggle Switch 8 unless you intend to reset the user configured
passwords to their factory default settings.
!
CAUTION
2
Caution: Do not toggle Switch 7 unless you intend to reset the user parameters
to the factory default settings.
Ring Speed
The module defaults to a 16Mbps ring speed on all rings. This may be changed
though local management.
2-6
Installation
Multi-Ring Out Capability
Any port of the module may be configured as a ring-out port through
management software. In this configuration a stand-alone passive concentrator
(such as an IBM 8228) may be added to the ring as shown in Figure 2-5. This
allows for a star-wired network with the SmartSwitch 9000 at the center. Consult
the SmartSwitch 9000 Local Management Guide for information on configuring the
ports.
TOKEN RING
9T122-24
SMB
FNB
CPU
9T122-24
2
1
16 Mb
1
2
3
4
5
6
7
8
IBM 8228™
9
STP Cable
10
11
12
Figure 2-5. Using a Ring-Out Port
2-7
Installation
2-8
Chapter 3
Operation
The 9T122-24 MicroLAN Module provides connectivity between the front panel
Token Ring(s) and the FDDI rings on the backplane (FNB-1 or FNB-2).
SmartSwitch 9000 modules connect to either the Internal Network Bus (INB) or
the Flexible Network Bus (FNB) bus. The 9T122-24 module connects to the FNB
configured as one Token Ring (factory default) or as two rings. In the two-ring
configuration, the rings function as individual networks, each with 12 ports.
Bridging/ Routing may occur between these two rings and/ or to any other
SmartSwitch 9000 module via the FNB.
DC/DC
Converter
SMB-1
System
Diagnostic
Controller
SMB-10
Twelve
Front Panel
Connections
FNB-1 or
FNB-2
i960 PLUS Core
Twelve
Front Panel
Connections
Figure 3-1. 9T122-24 Block Diagram
3-1
Operation
Bridging
The 9T122-24 is configured for SRT bridging. It will pass SR (Source Routing)
frames between the rings and provides translation to transparent frames over the
FNB to Ethernet and FDDI modules. For information on configuring the bridging
function, see the addendum to the SmartSwitch 9000 Local Management User’s
Guide, containing information specific to this module.
Transparent Bridging
Transparent Bridging is accomplished by building a Source Address Table (SAT)
from source MAC/ physical addresses and using the SAT to make forwarding
decisions.
The 9T122-24 prevents unnecessary network traffic from passing through the
module by implementing two separate filtering processes — IEEE 802.1d or
Cabletron’s Special Filtering Database. These processes may be used individually
or in tandem.
The first process, the IEEE 802.1D filtering process, begins with the creation of a
list of local node addresses in the SAT. When the 9T122-24 first goes on-line, it
initially forwards all packets across the bridge. After receiving a packet on the
bridge port, the 9T122-24 learns the address of the sending node from the packet
and stores that address in the SAT. In this manner, the bridge learns the address of
each node on each side of the bridge. The bridge then uses the addresses stored in
the table to compare the destination address of each subsequent packet that
travels to the bridge. If the destination address of a packet resides on the bridge
segment, the 9T122-24 does not forward across the Token Ring link.
The second filtering process, the Cabletron Systems Special Filtering Database,
provides an additional step in the filter/ forward decision. Through Remote
Management, you can define up to 10 additional filtering parameters for
incoming network traffic. These parameters include (but are not limited to) the:
•
•
•
•
Destination address
Source address
Type field (protocol)
64 bytes of the data field (using a data offset)
For example, using this process, you can ensure that the 9T122-24 always filters or
forwards packets with a specific protocol or address.
3-2
Operation
Source Route Bridging
Source Route Bridging operates by transmitting frames over a designated route.
Unlike Transparent Bridging, all devices in a Source Route Bridged (SRB) network
“know” the locations of other stations within the network. Using a portion of the
MAC frame header known as the RIF (Routing Information Field), the source
device determines the route for the frames it sends.
In order for source routing to work, the source station must determine the proper
route to reach the desired destination. To accomplish this:
1. The source station sends out frames called All Route Explorer (ARE) or Single
Route Explorer (SRE) frames onto the network. All Source Route Bridges
recognize these frames and forwards them to their outbound ports.
2. The receiving bridges append their own route information to the Route
Information Field (RIF) in the MAC frame header and transmit the frame
again.
3. Eventually, the original source device receives all of the ARE replies from the
other end stations on the network.
4. From this information, the source device can determine a desired route for
each frame it transmits.
Spanning Tree Algorithm
The 9T122-24 promotes maximum network use in multiple-bridge environments.
A bridge learns the bridge topology of its network from bridge protocol data that
it receives from other bridges within the network. The bridges then apply the
Spanning Tree Algorithm (STA) to select a root bridge, and then determine
primary data paths within potential data loop configurations.
Spanning Tree Algorithm is a hierarchy (or tree) of priorities that bridges establish
between themselves. This hierarchy guarantees that primary and redundant data
paths are clearly defined at all times, so that the network is continuously available
to users.
In a multiple-bridge environment, one bridge in the network establishes itself as
the root bridge. As the root, this bridge has priority over all other bridges. In a
Spanning Tree, all of the bridges must determine which bridge is the root, and
then determine their own relative priority within the network.
3-3
Operation
Flexible Network Bus (FNB)
The FNB consists of two dual FDDI networks, the FNB-1 and FNB-2, providing
up to 400 Mbps of data bandwidth. These FDDI networks are 100% ANSI
FDDI-compliant supporting SMT (version 7.3), MAC, PHY, and PMD standards.
This allows the FNB to traverse multiple SmartSwitch 9000 hubs, or connect to
any ANSI FDDI-compliant device, through standard A/ B port connections, using
the FDDI repeater module.
System Management Buses
There are two management channels within the SmartSwitch 9000 system: the
SMB-1 and the SMB-10. These buses provide out-of-band management and inter-
module management communication.
SMB-1 Bus
The SMB-1 is a 1Mbs management bus located within the SmartSwitch 9000. This
bus is utilized by all diagnostic controllers in the system including connectivity
modules, power supply modules and the environmental module. The SMB-1
transports inter-chassis information between system components, such as power
and environmental information, as well as diagnostic messages. Periodic
loop-back tests are preformed by all modules that share this bus to ensure the
validity of SMB-1. In the event a failure is detected on SMB-1, the SMB-10 may be
used as an alternate communication channel.
SMB-10 Bus
The SMB-10 is a 10Mbs management bus located within the SmartSwitch 9000
that is also used for inter-chassis communication of modules, as well as serving as
an out-of-band management channel into the SmartSwitch 9000. The SMB-10 is
externalized from the chassis via an optional Ethernet Port Interface Module
(EPIM) located on the front of the Environmental Module. Through an EPIM
connection, full SNMP management of the SmartSwitch 9000 is available out-of-
band from user data. Modules that share the SMB-10 bus periodically send out
loop-back packets to ensure the validity of SMB-10. In the event a fault is detected
on the SMB-10, the SMB-1 can be used as an alternate communication channel by
the modules.
3-4
Operation
System Diagnostic Controller
This diagnostic controller is composed of a Z-80 microprocessor and its
supporting logic. The diagnostic controller is designed to control the power-up
sequencing of modules, monitor the 9T122-24 input and output power
parameters, keep watch over the main host processor, as well as monitor the
temperature and control the SMB LANVIEW diagnostic LED. Although the
diagnostic controller and the main host processor can operate independent of
each other if needed, they exchange information about each other’s status and
overall module condition. The information gathered by the diagnostic controller
is available to the network manager via local/ remote management and the LCD
located on the environment module. The 9T122-24 has been designed so that in
the event of a diagnostic controller fault, the module will continue to function.
DC/DC Converter
The DC/ DC converter converts the 48 VDC on the system power bus to the
necessary operating voltages for its host network services module. The diagnostic
controller controls the operation of the DC/ DC converter.
FNB Interface
SmartSwitch 9000 modules are designed with one of two attachment policies. One
allows a module to dual attach to either FNB-1 or FNB-2; the second allows dual
attachment to both FNB-1 and FNB-2. The 9T122-24 have one dual attachment to
the FNB backplane, connecting to either FNB-1 or FNB-2. The module can insert
into the FNB or bypass it. These flexible configuration options make the
SmartSwitch 9000 ideal for networks designed to Bridge/ Route multiple lower
speed LANs to FDDI and/ or networks designed using an FDDI collapsed
backbone.
i960 Core
The i960 core in the FNB module serves two major functions: it provides the
packet forwarding logic and performs all network management services. FNB
modules can be configured to run as layer 2 bridges, layer 3 routers or as
SecureFast Packet Switches. It is possible to run the bridging and routing options
concurrently, but the SFPS option cannot run with bridging and routing.
3-5
Operation
The i960 core provides the SNMP protocol stacks, as well as support for industry-
standard MIBs. Additionally, Cabletron enterprise-extension MIBs are supported
for each media type. Advanced management services, such as the Distributed
LAN Monitor, RMON, telnet and network address to MAC address mapping,
are also provided by the i960 core.
3-6
LANVIEW LEDs
The functions of the two System Status LEDs, System Management Bus (SMB)
and the CPU, are listed in Table 4-1.
Table 4-1. System Status LEDs (SMB and CPU)
LED Color
State
Description
Fully operational.
Green
Yellow
Functional
Crippled
Booting
Reset
Not fully operational (i.e., one bad port).
Blinks yellow and green while booting.
Normal power-up reset.
Yellow/ Green
Red
Red (Flashing)
Off
Failed
Fatal error has occurred.
Power off
Module powered off.
The functions of the FNB receive LED are listed in Table 4-2.
Table 4-2. FNB Receive LEDs
LED Color
State
Red
Red (Flashing)
Green
No link, Port disabled
Link, Port disabled
Link, No activity, Port enabled
Activity (Flashing rate indicates rate of activity).
No activity
Yellow (Flashing)
Off
The functions of the FNB transmit LED are listed in Table 4-3.
Table 4-3. FNB Transmit LEDs
LED Color
State
Red
Port disabled
Fault or Error (Flashing rate indicates rate)
Port in standby state
Red (Flashing)
Yellow (Flashing)
Green (Flashing)
Off
Activity (Flashing rate indicates rate of activity).
No activity
4-2
LANVIEW LEDs
The functions of the Token Ring Mac receive LEDs are listed in Table 4-4.
Table 4-4. Token Ring Receive LED
LED Color
State
Red
Red (Flashing)
Green
No link, Port disabled
Link, Port disabled
Link, No activity, Port enabled
Yellow (Flashing) Link, Activity (Flashing rate indicates rate of activity).
Off No link, No activity, Port enabled
The function of the Token Ring Mac transmit LEDs are listed in Table 4-5.
Table 4-5. Token Ring Transmit LED
LED Color
State
Red
Port Disabled
Fault, Ring is Beaconing
Red (Flashing)
Green (Flashing)
Yellow (Flashing)
Off
Activity (Flashing rate indicates rate of activity).
Port in standby state, Link
No activity, Port enabled
The functions of the Link LED are listed in Table 4-6.
Table 4-6. Port Link LEDs
LED Color
State
Red
Red (Flashing)
Green
No link, Port disabled
Link, Port disabled or Speed fault
Link, Port enabled
Off
No link, Port enabled
4-3
Chapter 5
Specifications
Safety
It is the responsibility of the person who sells the system to which the module will
be a part to ensure that the total system meets allowed limits of conducted and
radiated emissions.
!
CAUTION
This equipment meets the safety requirements of:
•
•
•
•
•
•
•
•
UL 1950
CSA C22.2 No. 950
EN 60950
IEC 950
EMI Requirements of FCC Part 15 Class A
EN 55022 Class A
VCCI Class I
EMC requirements of:
EN 50082-1
IEC 801-2 ESD
IEC 801-3 Radiated susceptibility
IEC 801-4 EFT
Service
MTBF (MHBK-217E)
MTTR
>200,000 hrs.
<0.5 hr.
5-1
Specifications
Physical
Dimensions:
35.0 D x 44.0 H x 3.0 W centimeters
(13.8 D x 17.4 H x 1.2 W inches)
Weight:
Unit:
1.36 kg. (3lb)
Shipping:
1.81 kg. (4lb)
Electrical
CPU:
i960
Shared DRAM Memory:
4Mb (expandable to 12 Mb)
4Mb (expandable to 12 Mb)
2Mb (expandable to 14 Mb)
(2) Texas Instruments TMS380C26 Controllers
128 Kb
Local DRAM Memory:
Flash:
Token Ring Interfaces:
NVRAM:
5-2
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