GarrettCom Switch DS 880 User Manual

Magnum DS 880  
10 / 100 Dual-Speed  
Stackable Hubs  
Installation and User Guide  
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Magnum DS880 Dual-Speed Stackable Hubs  
Installation and User Guide (05/01)  
Contacting GarrettCom, Inc  
Please use the mailing address, phone and fax numbers and email address listed below:  
GarrettCom, Inc.  
47823 Westinghouse Dr.  
Fremont, CA 9453-7437  
Phone (510) 438-9071  
Fax (510) 438-9072  
Federal Communications Commission  
Radio Frequency Interference Statement  
This equipment generates, uses and can radiate frequency energy and if not  
installed and used properly, that is in strict accordance with the manufacturer's  
instructions, may cause interference to radio communication. It has been tested and  
found to comply with the limits for a Class A computing device in accordance with the  
specifications in Subpart J of Part 15 of FCC rules, which are designed to provide  
reasonable protection against such interference when operated in a commercial  
environment. Operation of this equipment in a residential area is likely to cause  
interference, in which case the user at his own expense will be required to take whatever  
measures may be required to correct the interference.  
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Magnum DS880 Dual-Speed Stackable Hubs  
Installation and User Guide (05/01)  
The Magnum Line  
ETHERNET C ONNEC TIVITY PRODUC TS  
"DESIG NED AND MANUFAC TURED IN THE USA"  
OVERVIEW  
GarrettCom, Inc.offers the premium-quality Magnumline of Ethernet LAN  
connectivity products with industry-standard functionality and built-in fiber  
configurability. Magnum products are designed for use in demanding Carrier Class,  
Industrial Grade and OEM applications where reliability is a primary consideration.  
4K-Series Switches, 100 & 10Mbps, copper ports with optional fiber  
port, with auto-negotiating full switching performance  
Quad-Series Fiber Switches, 100 & 10Mbps, fiber and copper ports,  
mixed-speed and mixed-media types, full switching performance  
“Outdoor” Ethernet Switch, for temperature uncontrolled locations  
6 10/100 and 2 100Mb fiber ports, can be connected in strings  
Mixed-Media Fiber Hub, 16-port Stackable, 10/100 auto-sensing  
Dual Speed 8-port and 16-port Stackables, 10/100 auto-sensing  
Stackable Hubs, SNMP Optional  
10Mb series and 100Mb series, both w/ optional port modules  
Personal Switches, 10/100Mb  
8 port dual speed, Auto-negotiable with fiber option  
Personal Hubs, 100Mb or 10/100Mb  
8-port, with two switched ports (1 fiber built in)  
Personal Hubs, 10Mb series  
8-port + AUI, stackable to 5 high, + optional BNC of fiber port  
8 or 9-port and 4 or 5-Port Personal Hubs, w/ man. up-link sw.  
Media Converters, 10Mb and 100Mb series  
All media combinations, incl. fiber ST, SC, mm., single mode  
The “X-line” of configurable MiXed Media products:  
Stackable Concentrators, SNMP optional, 13-Ports  
Mini-Concentrators, 7 Ports, Repeaters, 2-Ports  
Repeater Port Modules (RPMs), 6 types for Ethernet media  
Bridge Port Modules (BPMs), 4 types, for segment isolation  
Fan-Outs, 10Mb series  
2, 4 and 8 Port Models  
Transceivers, 10Mb and 100Mb series 10Mb Mini-Transceivers  
and Coax Models, All Types - Apr, 01  
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Installation and User Guide (05/01)  
TABLE OF CONTENTS  
PAGE  
1.0 SPECIFICATIONS...................................................................................................... 1  
1.1 Technical Specifications ..................................................................................... 1  
1.2 Ordering Information .......................................................................................... 3  
2.0 INTRODUCTION ....................................................................................................... 4  
2.1 Inspecting the Package and Product.................................................................... 4  
2.2 Product Description............................................................................................ 5  
2.2.1 Magnum DS880 Chassis ......................................................................... 7  
2.2.2 10 / 100 Speed Auto-sensing................................................................... 7  
2.3 Stacking Magnum DS880’s ............................................................................... 8  
2.4 Bridge Module between the 10Mb and 100Mb Domains ................................... 9  
2.5 Up-link Switch on Port # 8 for Cascading........................................................... 9  
2.6 Features and Benefits........................................................................................ 10  
2.7 Applications ...................................................................................................... 11  
3.0 INSTALLATION ...................................................................................................... 13  
3.1 Locating Magnum DS880 Dual-Speed Hubs.................................................... 13  
3.1.1 Table-Top or Shelf Mounting................................................................ 13  
3.1.2 Wall (or Vertical Surface) Mounting..................................................... 13  
3.2 Connecting Ethernet Media............................................................................. 14  
3.2.1 Connecting Twisted Pair (CAT3, CAT5).............................................. 14  
3.2.2 Collision Domain Diameter, Cable Distances and PDV Calculations... 14  
3.2.3 Connecting to NICs which support Auto-Negotiation........................... 17  
3.3 Powering the Magnum DS880 .......................................................................... 18  
4.0 OPERATION............................................................................................................. 18  
4.1 Dual-Speed Functionality................................................................................ 18  
4.1.1 Software Transparency........................................................................... 20  
4.2 Port Speed settings for 10,100 and 10/100Mbps Mode only........................... 20  
4.3 Auto-negotiation and speed-sensing ................................................................ 21  
4.4 LEDs ................................................................................................................ 21  
4.5 Up-link Switch.................................................................................................. 21  
5.0 TROUBLESHOOTING............................................................................................. 22  
5.1 Before Calling for Assistance ........................................................................... 22  
5.2 When Calling for Assistance............................................................................. 23  
5.3 Return Material Authorization (RMA) Procedure............................................. 23  
5.4 Shipping and Packaging Information................................................................ 24  
APPENDIX A: WARRANTY INFORMATION ................................................................ 24  
APPENDIX B: OPTIONAL 48VDC POWER SUPPLY, ADDENDUM ........................... 25  
Revisions  
Rev C 05/01 : Change the company name to GarrettCom, Inc. (Formerly it was Garrett  
Communications). There are no changes to the content of the material at this time  
Rev B 02/99 : Added optional 48vdc power supply addendum; Port Speed settings for  
10,100 and 10/100Mbps Mode only; Connecting to NICs which support Auto-  
Negotiation information; and Collision Domain Diameter, Cable Distances and PDV  
calculations.  
Rev A 10/97 : This revision is the initial release of the DS880 Dual Speed  
Stackable Hubs user manual.  
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Magnum DS880 Dual-speed Stackable Hubs  
Installation and User Guide(05/01)  
1.0  
1.1  
SPECIFICATIONS  
Technical Specifications  
100 or 10 Mb/s per port, auto-sensing for speed. DS880 hubs support  
two traffic domains, one at 100Mb/s and one at 10Mb/s, have eight RJ-45  
ports, and are stackable up to 3 units high operating as one repeater.  
Performance  
When a port is operating at 100Mb/s:  
Data Rate: 100 Mb/s  
PDV (Path Delay Value) : 80BT, exceeds Class II  
When a port is operating at 10Mb/s:  
Data Rate: 10 Mb/s  
Partitioning: Enforced after 63 consecutive collisions  
Auto-reconnect: Occurs after one packet of error-free reception  
Network Standards  
100Mb: Ethernet IEEE 802.3u , 100BASE-TX  
10Mb: Ethernet IEEE 802.3, 10BASE-T  
Auto-sensing for speed: IEEE 802.3u  
Packet-Processing Between Domains (internal 10/100 switch or bridge)  
Filtering and Forwarding Rate from 100Mb ports: 148,800 pps max  
Filtering and Forwarding Rate from 10Mb ports: 14,880 pps max.  
Processing type : Store and Forward  
Auto-learning : 8K address table, shared for both traffic domains  
Packet buffers : 2MB,dynamically allocated & shared on both domains  
Latency (not including packet time) : 100 to 10Mb : 5µs  
10 to 100Mb : 5µs  
CPU Type : State Machine  
Maximum Ethernet Segment (or Domain) Lengths  
10BASE-T (Unshielded twisted pair)  
- 100 m (328 ft)  
100BASE-TX (CAT 5 UTP)  
- 100 m (328 ft)  
Operating Environment  
Ambient Temperature:  
Storage Temperature:  
32ºF to 122ºF (0ºC to 50ºC)  
-20ºC to 60ºC  
Ambient Relative Humidity: 10% to 95% (non-condensing)  
Power Supply (Internal  
)
AC Power connector : IEC-type, male recessed, rear of chassis  
Power Input Voltage : 90 to 260 VAC (auto ranging)  
Power Input Frequency : 47-63 Hz  
Power Consumption : 20 watts max  
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Magnum DS880 Dual-Speed Stackable Hubs  
Installation and User Guide (05/01)  
(1.1 Technical Specifications, continued)  
48VDC Power Supply (Optional  
)
Power Input Voltage : 36 to 72 VDC (auto ranging)  
Terminal Block in rear: “-, GND, +”  
Power Consumption: 20 watts max.  
Network Cable Connectors - for the eight RJ-45 shielded female ports per hub  
100Mb: Category 5 UTP/STP  
10Mb: Category 3, 4, 5 UTP (Note: speed-sensing does not sense cable type)  
Stacking Cable - stacking may be up to four DS880 hubs, or 32 ports  
A stacking cable with 50-pin “SCSI” male connectors, shielded, 9 inches (23 cm)  
long, is included with each Magnum DS880-A Dual-Speed add-on unit.  
Switch, Manual  
UP-LINK : MDI-X thumb-operated slide switch, converts RJ-45 port #8 from a  
regular (=position) user segment port to a crossover (X position) up-link port for  
On/Off connection to a central hub or another cascaded hub. The up-link port #8  
is auto-sensing for speed, and the up-link works the same at 10Mb or 100Mb.  
Packaging  
Enclosure: High strength metal. Metal mounting brackets included.  
Suitable for wiring closet shelf, wall or desktop mounting.  
Dimensions: 9.75 in D x 8.5 in. W x 1.4 in. H ( 25cm x 22cm x 3.5cm)  
Weight: 2.5 lb. ( 1.15 Kg)  
Cooling method: Fan cooled, internal @ 9 cfm  
LED Indicators  
PWR : Steady On when power applied  
BR : Bridge Module Indicator, On when 10/100 bridge module is installed  
(Model DS880-B), Off when no bridge module is inside (DS880-A)  
COL : Collision LEDs, one each for 100Mb and 10Mb speed domains  
ACT : Common packet activity indicator, one for each traffic domain  
100 (per port): Steady On when speed is 100Mbps , Off when speed is 10Mb,  
flashing when auto-negotiating or when not connected (no LINK)  
LK (per port): Steady On when twisted-pair link is operational  
RX (per port): Activity, flashing when port is receiving data  
Agency Approvals  
UL Listed (UL 1950), cUL, CE  
Emissions: meets FCC Part 15, Class A  
Optional: NEBS L3 Certified  
Warranty  
Three years, return to factory  
GarrettCom com  
Made in USA  
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Magnum DS880 Dual-Speed Stackable Hubs  
1.2 Ordering Information  
Installation and User Guide (05/01)  
Magnum DS880 Dual-Speed Stackable Hubs  
Magnum DS880-A:  
Dual-Speed 10/100 Stackable Hub with eight RJ-45  
ports, each auto-sensing for 100Mb or 10Mb operation. Stackable  
up to three units high, with all ports in one stack operating as two  
separate traffic domains, one domain at 100Mb/s and one domain  
at 10Mb/s. Includes stacking cable, internal auto-ranging power-  
supply, cooling fan, and metal brackets for shelf or wall mounting.  
Magnum DS880-B:  
Same as Magnum DS880-A but includes an internal  
switch module that bridges the two traffic domains, filtering and  
selectively forwarding packets between the 100Mb and the 10Mb  
domains. Stacks up to three DS880-A units. One DS880-B unit per  
stack supports all ports at 100Mb or 10Mb communicating with  
each other. The internal switch has 2Mb dynamic store-and-  
forward packet buffers and 8K node addresses.  
GarrettCom reserves the right to change specifications, performance  
characteristics and/or model offerings without notice.  
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Magnum DS880 Dual-Speed Stackable Hubs  
Installation and User Guide (05/01)  
2.0  
2.1  
INTRODUCTION  
Inspecting the Package and Product  
Examine the shipping container for obvious damage prior to installing this product;  
notify the carrier of any damage which you believe occurred during shipment or delivery.  
Inspect the contents of this package for any signs of damage and ensure that the items listed  
below are included.  
This package should contain:  
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1
1
Magnum DS880-A or DS880-B Dual-Speed Hub Unit  
AC Power Cord (U.S. and other 115 vac locations only)  
Stacking Cable, Model DS880-A add-on (no bridge inside) units only  
Set of metal clips and screws for wall-mounting  
Installation and User Guide  
Product Registration Card  
Remove the Magnum DS880 Dual-Speed Hub from the shipping container. Be sure to  
keep the shipping container should you need to ship the unit at a later date. To validate the  
product warranty please complete and return the enclosed Product Registration Card to  
GarrettCom, Inc. as soon as possible.  
In the event there are items missing or damaged contact your supplier. If you need to  
return the unit use the original shipping container. Refer to Chapter 5, Troubleshooting, for  
specific return procedures.  
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Magnum DS880 Dual-Speed Stackable Hubs  
2.2 Product Description - General  
Magnum DS880 Dual-Speed hubs have eight RJ-45 ports, each 10/100Mb auto-  
Installation and User Guide (05/01)  
sensing. Each port can independently identify (via IEEE 802.3u auto-sensing) and accept either  
100Mb or 10Mb Ethernet signals, adapting to match the best speed of the connected device.  
There are two internal traffic domains in Magnum DS880 hubs, one for the 100Mb traffic and  
one for the 10Mb traffic. The 100Mb users share the 100Mb domain’s bandwidth and the 10Mb  
users share the 10Mb domain’s bandwidth.  
Any DS880 port can connect into either the 100 or the 10Mb traffic domain, and can  
also change from one traffic domain to the other at any time without affecting the speed of other  
ports. The automatic per-port speed-sensing is continuous, allowing the connected devices to  
change speed at any time without impairing the operation of the other ports and connected  
devices.  
DS880A  
10Mb Hub  
100Mb Hub  
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UPLINK  
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Stackable  
PWR  
8000E  
AC  
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LK  
RX  
Hub  
GARRETT  
C
OL  
Figure 2.2.1 : Magnum DS880 is functionally both a 10Mb and a 100Mb hub in one  
As Magnum DS880 Dual-Speed units are stacked, the two shared traffic domains  
automatically expand to support all of the ports in the stack. Any combination of 10Mb and  
100Mb ports, up to the maximum of 32 ports (4 units) in one stack, can be in use at any time.  
One DS880 Model, the Magnum DS880-B, includes an internal bridge or switch  
module which interconnects the 10 Mb and the 100Mb traffic domains. This enables all users on  
a DS880-B hub or a DS880 stack, whether 100Mb or 10Mb, to talk to each other. The internal  
switch of the DS880-B filters and selectively forwards packets between the 10Mb and the  
100Mb domains, maintaining peak performance in each domain unaffected by local traffic in the  
other domain. The internal bridge is self-learning, with large address table capacity for up to 8K  
node addresses. As networked nodes are added or removed or move from one speed domain to  
the other, the DS880’s internal switch automatically keeps track.  
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Magnum DS880 Dual-Speed Stackable Hubs  
Installation and User Guide (05/01)  
2.2  
Product Description - General (continued)  
Bridge Module  
DS880B  
DS880A  
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PWR BR  
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UPLINK  
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CO  
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LK  
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X
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PWR  
BR  
UPLINK  
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AC  
CO  
T
LK  
RX  
L
Figure 2.2.2 : DS880B is a DS880A with a bridge module built-in for 10 to 100 bridging  
Only one DS880-B unit is needed to support a stack. Additional 8-port units of the  
DS880-A “add-on” hubs . . . units that do not have the bridge module inside, and which cost less  
accordingly . . . can be added to the stack, up to the 4-unit stack maximum. In a stack, the  
DS880-B unit (illustrated below as the bottom unit) can be in any stack position.  
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UPLINK  
UPLINK  
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LK  
RX  
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COL  
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A
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PWR BR  
100  
LK  
RX  
ACT  
COL  
100 10  
PWR BR  
UPLINK  
100  
LK  
RX  
ACT  
COL  
100 10  
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PWR BR  
UPLINK  
100  
LK  
RX  
ACT  
COL  
B
100 10  
Figure 2.2.3 : Stack of DS880’s, 3 @ DS880A’s and 1 @ DS880-B  
DS880-A units can also be used without a DS880-B, whereupon they will function as  
dual-speed stackable hubs. This could be desired if there is an external non-auto-sensing switch  
(such as the Magnum 300ES Two-Port Switch) available to interconnect the two speed domains,  
or if only 100Mb devices are connected and the 10Mb domain is unused (or vice-versa), or if  
dual-speed operation with two unconnected and uncoordinated domains is needed for the  
application.  
Each DS880 has its own internal power supply, and is easily added to an existing 10  
or 100Mb network. DS880s are suitable for wiring closet shelf, table-top or vertical mounting.  
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Magnum DS880 Dual-Speed Stackable Hubs  
2.2.1 Magnum DS880 Chassis  
The Magnum DS880 chassis houses one main PC board, a bridge module daughter-  
Installation and User Guide (05/01)  
board in the Model DS880-B, and an internal power supply unit. The front side of the chassis  
has eight RJ-45 twisted-pair ports and one cascading (UP-LINK) switch for Port 8 on the right.  
LEDs to indicate operating status are on the left front side. There are power (PWR)  
and bridge-inside (BR)  
indicators for the unit.  
There are activity (ACT)  
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8
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PWR BR  
UPLINK  
100  
LK  
RX  
ACT  
COL  
and collision (COL)  
100 10  
indicators for each of the  
10Mb and 100Mb domains,  
Magnum DS880 Dual-Speed Hub  
set unto a “square” arrangement, for visual indication of the operating status of each domain.  
And there are link (LK), receive (RX) and speed (100) indicators for each port. (See Section  
1.1 “Specifications” for a technical description of the LEDs). The unit has a cooling fan on the  
bottom left corner which sends warm air out away from the unit to the rear. Stacking cables  
connect in the rear (see Section 2.3 for stacking information).  
The AC power cord connector, a universal recessed-male IEC type, is in the left  
rear of the chassis. The internal power supply is auto-ranging for any AC power input of 115 -  
230 vac, 50 - 60 Hz. (An internal DC power supply is optional).  
2.2.2  
10 / 100 Speed Auto-sensing  
All eight RJ-45 twisted pair ports support auto-sensing for speed, independent of the  
other ports. Speed-sensing is performed by the DS880’s electronics in accordance with the  
standards of the IEEE 802.3u auto-negotiation standard. If the connected device or node  
indicates that it is capable of 100Mb speed, then operation on that port will be at 100Mb/s. If  
the connected device does not positively indicate that it is capable of 100Mb speed, then the  
operation on that DS880 port will be at 10Mb/s. Of course, the hubs’ auto-negotiation technique  
is only for 10 / 100 speed, and does not provide for any full-duplex operation.  
When a port is connected and LINK is present, the speed on that port that has been  
sensed by the DS880 hub will be indicated by the ‘100’ LED for that port. The ‘100’ LED is ON  
when 100Mb speed is sensed, and is OFF when 10Mb speed is in use. When a port is not  
connected, the ‘100’ LED corresponding to that port will be blinking to indicate that it is trying  
to auto-negotiate. (See section 4.3 for operation of the LED’s).  
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Magnum DS880 Dual-Speed Stackable Hubs  
2.3 Stacking Magnum DS880s  
Up to four Magnum DS880s can be stacked to operate as one 10/100 dual-speed  
Installation and User Guide (05/01)  
repeater with up to 32 dual-speed ports. Normally, one Magnum DS880-B hub per stack is  
needed to provide a  
switched interconnection  
between the two separate  
OUT  
OUT  
IN  
IN  
100Mb and 10Mb traffic  
domains in the stack.  
Additional stacked units  
are normally Model  
DS880-A “add-on” units,  
which cost less.  
OUT  
IN  
OUT  
IN  
FAN EXHAUST  
Figure 2.3 : Magnum DS880’s stacked. Cables connect between “Out” and “In” Ports  
The DS880-B models with the bridge module inside look the same as the DS880-A  
units (no bridge inside) from the outside. The “BR” LED on the front will light up when power  
is applied to indicate that a DS880 is a -B (bridge inside) model. (The “BR” LED will be off if  
the unit is a Model DS880-A). The DS880-B models cannot be stacked together, as their  
internal bridges would not be able to function properly when more than one is present. (Note  
that two DS880-B units may be cascaded to operate together, however). Use DS880-B models  
un-stacked, or with only 1 Model DS880-B in a DS880 stack. See Section 2.7, Example 3.  
When stacking DS880’s, please make sure to use only the shielded 9-inch long  
stacking cable provided with each DS880-A unit. The cable length is designed to provide  
proper operation of up to four DS880 units in a stack, and longer cables or unshielded cables are  
not permitted as they will not operate properly at 100Mb speeds.  
The 9-inch length is enough to provide for side-by-side stacking. This can be  
convenient when locating the DS880s in a rack, for example, as two DS880s will fit side-by-side  
on a tray in a standard 19” rack space.  
When connecting DS880s in a stack, use the stacking cable to connect the “Out”  
stacking port from one DS880 unit to the “In” stacking port of the other. Push in the cable  
connectors until they snap in firmly. Also, leave space in the left-rear area for the exhaust of the  
internal cooling fan in each DS880 unit. See Figure 2.3 above.  
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Magnum DS880 Dual-Speed Stackable Hubs  
Installation and User Guide (05/01)  
2.4  
Bridge Module between the 10Mb and 100Mb Domains  
Bridge Module  
Figure 2.4 : Internal view of  
DS880-B with bridge  
module installed  
Magnum DS880-B’s contain a factory-installed bridge module to interconnect the two  
traffic domains, filtering and selectively forwarding packets to allow only necessary packets to  
cross between the domains. This enables all of the users and nodes connected into either  
domain, whether 100Mb or 10Mb, to talk to each other, and it keeps local traffic on one domain  
from consuming any of the bandwidth of the other domain.  
The bridge operates in the store-and-forward mode, which filters out bad packets and  
maintains optimum performance in both domains. Packet forwarding delay is only 5µs (plus  
packet time), much less than traditional store-and-forward bridge products, enabling the  
DS880s to maintain high network performance. The bridge has 8K node address capacity,  
suitable for use in large networks. Addresses are self-learning so that filtering / forwarding of  
10Mb and of 100Mb packets is maintained correctly even when users move their connection, or  
change speed, or power down.  
The DS880-B’s bridge module is implemented as a daughter board. DS880 units have  
an LED on the front labeled ‘BR’ that will be ‘ON’ when the module is installed internally.  
Power any DS880 unit on and if the BR LED is ON, it is a Magnum DS880-B unit.  
NOTE : Only one Magnum DS880-B (with a bridge module built-in) is  
allowed per repeater stack. Thus, if the DS880s in a stack have more than one  
BR (bridge) LED ‘ON’, it is an illegal configuration.  
2.5  
Up-link Switch on Port 8 for Cascading  
The unit has an up-link switch for Port # 8, located on the right-front side of the hub.  
It enables the port’s cable to either connect to a user station ( = position) or to be cascaded to  
another hub (X position). (See Section 4.4 for more details about up-link). Like all DS880  
ports, Port # 8 is a dual-speed port which will sense the speed of the connected device. The up-  
link switch operates the same, whether Port # 8 is connected to either 100Mb or 10Mb devices.  
When the up-link port is used to cascade two DS880 hubs or stacks together, the auto-  
sensing feature will cause the connecting link to operate at 100Mb speed.  
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Magnum DS880 Dual-Speed Stackable Hubs  
2.6 Features and Benefits  
Supports 10 or 100Mb network connections on each of eight RJ-45 ports  
Installation and User Guide (05/01)  
Magnum DS880 Dual-Speed 10 / 100 hubs combine two logical hubs . . . one at 10Mb  
and one at 100Mb . . . in one physical box supporting two traffic domains. Each port  
can operate at either 10 or 100Mb, independently of the other ports.  
Auto-sensing for speed, 10 or 100Mb on each port  
All ports support 10/100 auto-negotiation for speed, operating separately on each  
port. Any mix of 10Mb and 100Mb users can be connected to the ports. Speed-  
sensing is continuous. Individual ports can change to 100Mb or 10Mb speed at any  
time, adapting automatically to any changes in the connected device’s speed. Speed-  
sensing complies with IEEE 802.3u, providing interoperability with other products.  
An internal switch connects the 10 and 100Mb domains on Model DS880-B  
Model DS880-B has an internal switch for filtering / forwarding traffic between the 10  
and 100Mb domains, allowing all connected devices to talk to each other. High  
performance switching provides full bandwidth in each domain, unaffected by local  
traffic on the other domain. One DS880-B per stack supports switching for all ports.  
Stackable for flexible expansion  
Magnum DS880s can be stacked up to four units high for 32 ports, each 10 / 100 dual  
speed. As additional units are added in a stack, the 10 and 100Mb traffic domains are  
expanded automatically to support the new ports at either 10 or 100Mb speed.  
Installation is “Plug and Play”, Operation is Transparent to Software  
The Magnum DS880-B operates as a hardware switch, only forwarding those packets  
from each domain that are needed on the other domain. Internal address tables are  
self-learning, enabling users to change port connections or 10 / 100 domains without  
affecting operations. The switch in the DS880-B will not affect any standard software  
applications or SNMP network management platforms.  
Small Enclosure Enables Use in Offices and Labs  
The compact packaging of Magnum DS880s allows them to be installed in offices and  
labs, or virtually any location within reach of a standard AC wall outlet. They comes  
in a durable metal enclosure for table-top or wall-mounting. They have an internal  
auto-ranging power supply for use worldwide. (Models with a 48vdc internal power  
supply are optionally available).  
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Magnum DS880 Dual-Speed Stackable Hubs  
2.7 Applications  
Installation and User Guide (05/01)  
Example 1 : A Magnum DS880-B serves a small office with mixed speed requirements. Some  
users operate at 100Mb, and some users and utility devices (such as print servers) run at 10Mb.  
All share the same hub, and talk to each other via the bridge module inside. Any node can  
change speed at any time without affecting network operation or impacting other users.  
1
2
3
4
5
6
7
8
PWR BR  
1
2
3
4
5
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7
8
UPLINK  
100  
LK  
RX  
ACT  
COL  
Print Server  
Router  
100  
100  
100  
Server  
10  
100  
100  
Users  
Figure 2.7.1 : DS880-B connects combinations of 10Mb and 100Mb network devices  
Example 2 : Where there are existing 10Mb hubs and users, they can easily be cascaded into  
any port of the DS880-B. This allows simple plug-and-play addition of 100Mb ports to an  
existing 10Mb network without having to change it. Nodes that are capable of 100Mb speed can  
be moved to any DS880 dual-speed port, and will automatically operate at the higher speed.  
The dual-speed ports on the DS880-B can be used for adding 100Mb users or for  
accommodating existing high performance users. The 100Mb traffic does not use the bandwidth  
of the 10Mb domain, so overall performance of the network is improved.  
Figure 2.7.2 :  
1
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5
6
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8
P
W
R
B
R
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PLIN  
K
10  
0
A
C
CT  
OL  
L
R
K
X
DS880-B adds a new  
100Mb domain to  
existing 10Mb  
network  
Print Server  
Router  
10 Mb Hub  
100  
100  
100  
Server  
1
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5
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7
8
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1
0
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1
1
2
100  
100  
Users  
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10  
10  
10  
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Magnum DS880 Dual-Speed Stackable Hubs  
Installation and User Guide (05/01)  
Example 3 :  
For additional expansion, DS880s can be expanded by stacking DS880-A “add-on”  
units. The additional stacked ports are all auto-sensing dual-speed, and can be used at either  
10Mb or 100Mb on a per-port basis.  
The stacking cables connect the DS880 units and carry the signals for both the 100Mb  
and the 10Mb domains. In a stack, all 10Mb ports are together in a 10Mb traffic domain while  
all 100Mb ports are similarly together on a separate 100Mb traffic domain. When one DS880-B  
unit with a bridge inside is present in a stack, its bridge will support all of the ports in the stack  
and enable network traffic to move between the two stacked domains.  
A Magnum DS880 stack operates as one dual-speed repeater. A dual-speed repeater is  
both a 10Mb hub and a 100Mb hub at the same time. This means that the 10Mb traffic domain  
obeys all of the rules of 10Mb shared Ethernet networks (hop counts, cable types, cable  
distances, etc.) and can be treated as one 10Mb repeater accordingly. Separately, the 100Mb  
traffic domain obeys all of the rules of 100Mb Fast Ethernet shared networks (hop counts,  
PDVs, cable types, cable distances, etc.) and can be treated as one 100Mb repeater. Both traffic  
domains function within the same physical DS880 hub or stack of hubs.  
1
1
1
2
2
2
3
3
3
4
4
4
5
5
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7
7
UPLINK  
PWR BR  
100  
A
C
CT  
OL  
LK  
RX  
1
0
0
1
0
UPLINK  
1
8
PWR BR  
100  
LK  
RX  
A
C
CT  
OL  
1
0
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0
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8
UPLINK  
PWR BR  
100  
LK  
RX  
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CT  
OL  
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1
0
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1
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5
6
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PWR BR  
UPLINK  
100  
LK  
RX  
A
C
CT  
OL  
1
0
0
1
0
Figure 2.7.3 :  
Stackof Magnum  
DS880’s operate as  
one 10/100 dual-speed  
repeater  
Print Server  
Router  
10 Mb Hub  
100  
100  
100  
Server  
1
2
3
4
5
6
7
8
9
10 11 12  
100  
100  
Users  
10  
10  
10  
10  
When expanding an Ethernet or Fast Ethernet installation, the Magnum DS880 Hubs  
are ideally suited for connecting servers and stations that have (or may have in the future ! )  
mixed speeds. Each traffic domain or segment has its own local traffic with the Magnum  
DS880-B performing bridge-isolation of one domain from the other, filtering and selectively  
forwarding 10Mb and 100Mb packets between the two domains. This keeps the traffic between  
the domains to a minimum and provides peak performance on both domains.  
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Magnum DS880 Dual-Speed Stackable Hubs  
3.0 Magnum DS880 Installation  
Installation and User Guide (05/01)  
Before installing the equipment, it is necessary to take the  
following precautions:  
1.) If the equipment is mounted in an enclosed or multiple rack  
assembly, the environmental temperature around the equipment must be  
less than or equal to 500C.  
2.) If the equipment is mounted in an enclosed or multiple rack  
assembly, adequate air flow must be maintained for proper and safe  
operation.  
3.) If the equipment is mounted in an enclosed or multiple rack  
system placement of the equipment must not overload or load unevenly  
the rack system.  
4.) If the equipment is mounted in an enclosed or multiple rack  
assembly, verify the equipment’s power requirements to prevent  
overloading of the building/s electrical circuits.  
5.) If the equipment is mounted in an enclosed or multiple rack  
assembly verify that the equipment has a reliable and uncompromised  
earthing path.  
6.) If the intra-building wiring (cabling) is involved with this  
product(NEBS), then it is recommended to have shielded cable and the  
shield is grounded at both ends.  
This chapter provides instructions for installing the Magnum DS880 hubs  
3.1  
Locating Magnum DS880 Dual-Speed Hubs  
The location of a Magnum DS880 Dual-Speed Hub is dependent on the physical  
layout of the network. Typically the hub is placed where combinations of 10Mb and 100Mb  
network devices need to be connected to communicate with each other. The compact size of the  
unit allows it to be conveniently placed in an office or lab area, and it can also be either shelf of  
wall-mounted (see instructions in 3.1.2 below). Wall-mounting brackets are included, usable for  
single units (but not for stacks). The width of two DS880 units will fit in a 19” rack when they  
are side-by-side.  
Locate an AC receptacle that is within six feet (2 meters) of the intended Magnum  
DS880 site. The rugged metal case of the Magnum DS880 will normally protect it from  
accidental damage in a lab or workplace setting. Maintain an open view of the front to visually  
monitor the status LEDs. Keep an open area around the unit so that cooling can occur from the  
small fan in the bottom-rear while the unit is in operation.  
3.1.1  
Table-Top or Shelf Mounting  
The Magnum DS880 Dual-Speed Hub can be easily mounted on a table-top or any  
suitable horizontal surface, and has four rubber feet to provide stability without scratching  
finished surfaces. When stacked, the rubber feet also provide separation between units for the  
exhaust of the rear cooling fan.  
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Magnum DS880 Dual-Speed Stackable Hubs  
3.1.2 Wall (or Vertical Surface) Mounting  
Each Magnum DS880 Dual-Speed Hub is shipped with two metal mounting brackets  
Installation and User Guide (05/01)  
(and screws) to allow the unit to be mounted in nearly any desired orientation or position. The  
brackets are attached to the metal hub case using one of the metal screws for each bracket and  
attaching to the Magnum DS880 through the round hole of the bracket. A user-supplied screw  
attaches the bracket to the mounting surface. It is recommended that the brackets be attached to  
two opposite corners of the unit. When properly attached, the brackets will extend slightly  
below the base of the unit to allow clearance for the rubber feet and the cooling fan exhaust.  
3.2  
Connecting Ethernet Media  
The Magnum DS880 Dual-Speed Stackable Hubs can be connected to the following  
two media types: 100BASE-TX and 10BASE-T. CAT 5 cables should be used when making  
100BASE-TX connections. When the ports are used as 10BASE-T ports, CAT 3 may be used.  
In either case, the maximum distance for unshielded twisted pair cabling is 100 meters (328 ft).  
Media  
IEEE Standard  
10BASE-T  
Connector  
RJ-45  
Twisted Pair (CAT 3)  
Twisted Pair (CAT 5)  
100BASE-TX  
RJ-45  
NOTE : It is recommended that high quality CAT. 5 cables (which work for both 10Mb and  
100Mb) be used whenever possible in order to provide flexibility in a mixed-speed  
network, since dual-speed ports are auto-sensing for either 10 and 100Mb/s.  
3.2.1  
Connecting Twisted Pair (RJ-45, CAT 3 or CAT 5, Unshielded or Shielded)  
The following procedure describes how to connect a 10BASE-T or 100BASE-TX  
twisted pair segment to the RJ-45 port. The procedure is the same for both unshielded and  
shielded twisted pair cables.  
1. Using standard twisted pair media, insert either end of the cable with an RJ-45 plug into  
the RJ-45 connector of the port. Note that, even though the connector is shielded, either  
unshielded or shielded cables and wiring may be used.  
2. Connect the other end of the cable to the corresponding device.  
3. Use the LINK LED to ensure proper connectivity by noting that the LED will be  
illuminated when the unit is powered and proper connection is established. For Port #  
8, if the LINK LED is not illuminated, change the setting of the up-link switch. If this  
does not help, ensure that the cable is connected properly and that the device on the  
other end is powered and is not defective.  
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Magnum DS880 Dual-Speed Stackable Hubs  
3.2.2 100Mbps Collision Domain Diameter, Cable Distances and PDV Calculations  
The 100Mbps Collision Domain Diameter is the length of the longest path between  
Installation and User Guide (05/01)  
any two devices in a single collision domain. A collision domain is defined as a cluster of  
network devices which are connected by means of a repeater or repeaters such that no bridging  
devices are present between any two devices in the cluster. In order to install an IEEE 802.3u  
compliant Fast Ethernet network, the collision domain . . regardless of the actual network  
topology . . must be less than 512 BT (Bit Times). Bit Times are related to media type as shown  
in Table 3.2.2a.  
Table 3.2.2a: Worst case round-trip delay for Fast Ethernet media*  
Media Type  
Round-trip delay in  
Bit Time per Meter (BT/m)  
Fiber Optic  
1.000  
1.112  
1.112  
1.140  
Shielded TP cable  
Category 5 Cable  
Category 3, 4 Cable  
*Worst case delays taken from IEEE Std 802.3u-1995, actual delays may be less for a particular cable.  
Contact your cable supplier for exact cable specifications.  
Each Fast Ethernet device component also has an associated BT delay which depends  
on the physical signaling system employed. Table 3.2.2b shows each Fast Ethernet device  
component and the associated BT delay. A “DTE” is an end node, such as a user station. Note  
that there is only one DTE pair associated with any device-to-device path.  
Table 3.2.2b: Worst case round-trip delay for Fast Ethernet device components*  
Component  
Round-trip delay in Bit Times (BT)  
2 TX DTEs  
2 FX DTEs  
100  
100  
1 FX and 1 TX DTE  
100  
1 T4 and 1 TX or FX DTE  
Class I Repeater  
127  
140  
Class II Repeater with any  
combination of TX and FX ports  
92 **  
**Note, the delay is only 80 Bit Times for  
the DS880, front-port-to-front-port.  
*Worst case delays taken from IEEE Std 802.3u -1995.  
To determine whether a prospective network topology adheres to the collision domain  
diameter specification, the following formula should be applied to the worst case path through  
the network. The worst case path is the path between the two Fast Ethernet devices (DTEs)  
which have the longest round-trip time.  
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PDV = (sum of cabling delays) + (sum of repeater delays) +  
(DTE pair delay) + (safety margin)  
PDV is the Path Delay Value of the worst case path. For the network to adhere to  
IEEE standard, this value must be less than 512 BT. The safety margin is specified in BT and  
may be a value between 0 and 5. This margin can be used to accommodate unexpected delays  
such as extra long patch cable. A safety margin of about 2 to 4 BT is recommended.  
A typical example of a PDV calculation is shown below, and is illustrated in Figure  
3.2.2a. Here, an integrator wishes to cascade the 100Mbps collision domains of two Magnum  
DS880 Hubs(each having a PDV of 80BT) for use with standard 100m Category 5 user cable  
segments (i.e. from computer to hub) and needs to know how long the inter-repeater Category 5  
cable segment, used to cascade the hubs, can be. The variable “X” represents the unknown  
maximum cascade cable delay.  
PDV = X + ((111 + 111) + (80 + 80) + (100) + 2 ) BT < 512 BT  
512 > (X + 486) BT  
X
< (512 - 486 ) BT, X < 28 BT  
Twisted Pair cable length, TL < (28 BT) / (1.112 m/BT)  
TL  
< 25 meters  
25 m maximum total length for Category 5 inter-repeater segment,  
Cat. 5 cable for  
cascading  
where 111 is the BT delay for  
1
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BR  
UPLINK  
1
7
2
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3
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ACT  
COL  
L
K
RX  
100m of Category 5 cable (1.112  
BT/m* 100m), 80 is the BT delay  
for each Magnum DS880, 100 is  
the BT delay for the TX DTE pair,  
and a safety margin of 2 was used.  
1
2
3
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5
6
7
8
PWRBR  
UPLINK  
1
7
2
8
3
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5
6
ACT  
COL  
LK  
RX  
100 m Cat. 5 cables  
to user devices  
100 m Cat. 5 cables  
to user devices  
Figure 3.2.2a: Two cascaded Magnum DS880 hubs  
The resulting value tells us that a Category 5 cable with a length of up to 30 meters  
may be used to cascade the Magnum DS880s. Note that this inter-repeater cable length may be  
increased by shortening the lengths of the 100m hub-to-user cable segments.  
It is also possible to cascade a group of up to nine Magnum DS880s (serving up to 56  
users with full-length 75m cables to each) by using short inter-repeater cable segments. The  
following is an example of how to calculate the maximum allowable cascade cable segment  
length. An illustration of this example is shown in Figure 3.2.2b, where the hub-to-user cable  
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Magnum DS880 Dual-Speed Stackable Hubs  
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lengths are up to 100 meters for Cat 5 twisted pair. The variable “X”, the maximum hub-to-hub  
cable delay, is calculated as follows:  
PDV = X + ((100) + (80 + 80 + 80 )+ (83 + 83) + 2 ) BT < 512 BT  
512 > (X + 508) BT,  
X
< 4 BT  
Twisted pair user cable length, TL < (4 BT) / (1.112 m/BT)  
TL < 3.6 meters for two hub-to-hub cascading cables  
2
meters (6 ft.) length max. for each of the cascade segments,  
In the above example, 80 is the BT delay for 75m of Category 5 cable (1.112 BT/m), 80 is the  
bit time delay for each Magnum DS880 front-to-front ports, 100 is the BT delay for the TX DTE  
pair in the user stations, and 2 BT is the safety margin applied.  
Figure 3.2.2b: Multiple  
1
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5
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8
PWR BR  
ACT  
UPLINK  
1
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2
8
3
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LK  
RX  
COL  
cascaded Magnum DS880 hubs  
Note that the cascading  
of multiple Magnum DS880 hubs  
is a capability beyond what  
1
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PWRBR  
UPLINK  
1
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PWR BR  
UPLINK  
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ACT  
COL  
LK  
RX  
ACT  
COL  
LK  
RX  
industry standards normally  
permit, and is different from what  
competitive Class II hub products  
normally allow. This additional  
cascading level and cable length is  
2 meter Cat. 5 cable  
for cascading  
All user devices connected  
via Cat. 5 twisted pair cable  
of up to 75m length.  
due to the relatively shorter bit time (80 BT actually measured, for front-port-to-port) delay of  
the 100Mbps domain of the Magnum DS880 vs. the industry standard delay of 92 BT for Class  
II repeaters. The installation flexibility and network growth potential is accordingly better with  
Magnum DS880s than with hubs that merely meet the standard.  
Table 3.2.2c shows maximum cable lengths for common network configurations using  
industry standard repeater PDV numbers. Calculations such as above should be performed  
using measured PDV data supplied by the equipment manufacturer in important installations.  
Table 3.2.2c: Maximum segment lengths for common network configurations  
Number Repeater  
of Hubs Hop Count  
Max. User  
Segment Repeater (Cascade)  
Max. Inter-  
Notes  
Lengths (m)  
100.0  
Length (m)  
n.a.  
1
2
2
3+  
www  
1
2
2
3
All ports TX  
100.0  
92.0  
60.0  
5.0  
20.0  
1.0  
All ports TX  
All ports TX  
All ports TX  
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Magnum DS880 Dual-Speed Stackable Hubs  
Installation and User Guide (05/01)  
Instructions for connecting the Magnum DS880 Dual-Speed Hubs to the various Fast  
Ethernet media are given in the following sections.  
3.2.3  
Connections to NICs which support Auto-Negotiation  
The Magnum DS880 Dual-Speed Hub will function properly with NICs (Network  
Interface Cards) which support Auto-Negotiation. The Magnum DS880 will establish link with  
any NIC which can send and receive the Fast Link Pulse (FLP) coding for the 100BASE-TX  
signaling system. When connecting a NIC to the DS880, it may be necessary to reload the NIC  
drivers on the user device if the NIC has been communicating with a protocol other than  
100BASE-TX (such as 10BASE-T). When 100Mb operation is agreed and in use, the 100Mb  
LINK/ACT LED is illuminated, steady ON if no traffic or blinking when there is traffic.  
3.3  
Powering the Magnum DS880  
Magnum DS880 Dual-Speed Hub incorporates an internal universal power supply, and  
has a recessed male IEC connector for the AC power cord in the rear. A six-foot 115 VAC 60Hz  
power cord is supplied with each unit shipped within the United States and Canada.  
Each Magnum DS880’s auto-ranging power supply supports installation environments  
where the AC voltage is from 90 to 260 volts with an input frequency between 47 and 63 Hz,  
and consumes a maximum of 20 watts. In order to power down the unit, simply unplug either  
end of the AC power cable.  
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Magnum DS880 Dual-Speed Stackable Hubs  
Installation and User Guide (05/01)  
4.0  
OPERATION  
This chapter describes the function and operation of the Magnum DS880 hubs.  
Dual-Speed Functionality  
4.1  
The Magnum DS880-A handles the two different traffic domains separately (unless it  
is stacked with a DS880-B). The DS880-B provides switched (bridged) connectivity between  
the Ethernet (10Mb/s) and Fast Ethernet (100Mb/s) domains. It joins the two network domains  
for unified operation, and filters/ forwards packets in both directions to maximize bandwidth  
utilization and performance. Magnum DS880s are hardware plug-and-play devices. There is no  
software set-up to be done at installation or for maintenance. The functions of the DS880s are  
described in this manual.  
Each time a packet is received on one domain of the bridge module, the decision is  
taken to either to filter or forward the packet. Errored packets are always filtered. For good  
packets, the filter and forward decisions are made based on the destination address contained in  
each packet. If the destination address is on the same domain from which the packet originated,  
then it is filtered and not forwarded to the other domain. If the destination address is not found  
to be a match in the address table for the originating domain, then it is forwarded to the other  
domain. If it is a new node address coming in which the switch did not previously know about,  
it “learns” the new address and puts it in the correct port address table. See “Address Learning”  
for more details.  
This diagram below shows the filter / forward logic for both domains.  
Magnum DS880-B  
10Mb Domain : 10Mb packets are  
100Mb Domain : 100Mb packets are  
forwarded when the destination address is  
NOT in the 100Mb domain address table.  
forwarded when the destination addresse is  
NOT in the 10Mb domain address table.  
10Mb Domain : 10Mb packets are  
filtered when the destination address is  
in the 10Mb domain address table.  
Bridge Module  
100 Mb Domain  
100 Mb Traffic  
10 Mb Domain  
10 Mb Traffic  
10  
BUS 100  
100Mb Domain : 100Mb packets are  
filtered when the destination address is  
in the 100Mb domain address table.  
Figure 4.1 : Filtering vs. Forwarding in Dual Speed 880-B  
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Magnum DS880 Dual-Speed Stackable Hubs  
Installation and User Guide (05/01)  
Packet  
Source  
10 Mb  
10 Mb  
10 Mb  
10 Mb  
100 Mb  
100 Mb  
100 Mb  
100 Mb  
Source  
Destination  
Address  
Not in table  
In table  
Not in table  
In table  
Not in table  
In table  
Address Table  
Filter/Forward  
Action  
Forward  
Filter  
Forward  
Filter  
Forward  
Filter  
Address  
Not in table  
Not in table  
In table  
Maintenance  
Add source to table  
Add source to table  
None  
In table  
None  
Not in table  
Not in table  
In table  
Add source to table  
Add source to table  
None  
Not in table  
In table  
Forward  
Filter  
In table  
None  
Table 4.1: DS880 Dual-Speed Hub Functionality  
1.  
Address Learning (Address Table Maintenance)  
The Magnum DS880-B bridge module is a state machine design which has a total  
address table capacity of 8K addresses. With a large address table, a Magnum DS880 can serve  
the needs of a medium-sized to large network. Table 4.1 shows what filter / forward action the  
Magnum DS880-B will take in each packet-processing situation, and when a new node address  
will be added to the internal Address Table. When a new node-address packet comes into a port  
for the first time, then the new source address is “learned” at the same time that the packet is  
forwarded. After learning, subsequent packets from the same node address are routinely  
processed. The address tables are flushed periodically to update the network status and to purge  
any inactive stations from the tables of both domains.  
2.  
Throughput Increase  
By selectively forwarding packets from each domain to the other domain based on its  
switching (bridging) logic, the Magnum DS880-B increases the available bandwidth for the  
users on both sides of the network. As shown in Figure 4.1, it keeps the local traffic on each side  
contained, preventing unnecessary packets and bad packets from traveling to the other domain  
and using up bandwidth needlessly over there. This results in more available network  
bandwidth on both sides and a throughput increase on for all users on both domains.  
1.1  
Software Transparency  
4.1.1  
The Magnum DS880-A and -B Dual-Speed Hubs need no software set-up and are  
transparent to system and application software, including network management  
software.  
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Magnum DS880 Dual-Speed Stackable Hubs  
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4.2  
Port Speed Settings for 10,100Mbps Or 10/100Mbps Mode only  
10/100  
Port 4  
100  
Port 3  
Port 2  
Port 1  
SW3  
SW2  
ON  
10/100  
OFF  
100  
Port 8  
Port 7  
Port 6  
Port 5  
ON  
OFF  
Figure 4.2: Switch Settings for 10/100Mbps and 100Mbps Speed  
The latest Magnum DS880 unit is equipped with Switches for setting Port Speed.  
The SW2 and SW3 switches are located on the right side of the main board as shown in the  
figure 4.2 above. These switches allow the user to set the speed at 10, 100Mbps or 10/100Mbps  
auto-sense. The unit has been set at 10/100Mbps at the time of shipping.  
The Switch SW3 represents port#1 to 4 and the switch SW2 port#5 to 8 as shown in the Fig 4.2  
above. The switches has 8 Dip-switches each. Every two contiguous Dip-switches represent one  
single port. To fix the speed at 100Mbps, both DIP-switch position have to slide towards the 100  
side. In the above Fig 4.2 the Switch SW3 has  
10/100  
been fixed 10/100Mbps and Switch SW2 at  
Port 4  
Port 3  
100Mbps. Setting the port at 10Mbps is little  
port# 1,2,3 has been fixed at 10Mbps  
Port 2  
bit tricky. The user has to slide the odd number  
Port 1  
of Dip-switch to ON (or 10/100) position and  
ON  
OFF  
even number to reverse  
Figure 4.2a Speed settings at 10Mbps (OFF or 100) position as shown in the Fig 4.2a above.  
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Magnum DS880 Dual-Speed Stackable Hubs  
4.3 Auto-negotiation and speed-sensing  
Installation and User Guide (05/01)  
All eight RJ-45 ports independently support auto-negotiation for shared  
10BASE-T and 100BASE-TX modes. When the ‘100’ LED is flashing, it means that the  
corresponding port is sending out auto-negotiation pluses out that port. When a connection is  
made, the other device should respond and both sides should agree to the speed being  
advertised. Depending upon the device connected, it will either advertise at 10Mb or 100Mb  
speeds. Silence means the port defaults to 10Mb.  
When the ‘100’ LED is steady ON, the port has auto-negotiated for 100Mb  
operation and is processing packets at 100Mb/s, When it is OFF, it is at 10Mb/s. If a DS880  
port is connected to a non-negotiating device, it will default to 10Mb speed. Since Magnum  
DS880s are hubs, they always operate in the shared or half-duplex mode on all ports.  
4.4  
LED’s  
PWR  
: Illuminates GREEN to indicate AC power is applied to the unit.  
BR  
: Bridge Module LED-  
ON when a bridge module is present in the unit (model DS880-B)  
OFF when no bridge module is present ( model DS880-A)  
: Two collision LED’s, one for each traffic domain, 10 and 100Mb  
Blinks intermittently when a collision occurs.  
COL  
ACT  
100  
: Activity (Send or Receive) for each traffic domain, 10 and 100Mb  
: Speed LED, per port. Flashing when auto-negotiating (No LINK)  
Steady ON when the port speed is 100Mbp/s, OFF for 10Mbp/s  
: LINK LED, per port. Illuminates GREEN when a working  
connection is established between the port and the attached device.  
: Activity LED, per port. Flashes GREEN to indicate that the port is  
receiving data from the attached device, i.e., there is activity on the  
port.  
LK  
RX  
4.5  
Up-link Switch  
The Magnum DS880s have one up-link slide switch,  
UP-LINK  
used with port 8. This allows repeater-to-repeater connections  
without a special cross-over cable. It works the same for 10Mb  
or 100Mb connections.  
Set the slide switch to the “=” position for twisted pair cabling from the DS880  
port to a user device, or to the “X” position for cross-over or up-link segment connections  
from the DS880 port to a repeater or hub. Verify proper switch position by noting the port’s  
LINK LED status, which is illuminated when a proper link is made.  
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Magnum DS880 Dual-Speed Stackable Hubs  
5.0 TROUBLESHOOTING  
All Magnum Ethernet products are designed to provide reliability and consistently  
Installation and User Guide (05/01)  
high performance in all network environments. The installation of the Magnum DS880 10/100  
Dual Speed Stackable Hub is a straightforward procedure (see INSTALLATION, Section 2.6);  
the operation is also straightforward and is discussed in Section 4.  
Should problems develop during installation or operation, this section is intended to  
help locate, identify and correct these types of problems. Please follow the suggestions listed  
below prior to contacting your supplier. However, if you are unsure of the procedures described  
in this section or if the Magnum DS880 10/100 Dual Speed Stackable Hub is not performing as  
expected, do not attempt to repair the unit; instead contact your supplier for assistance or contact  
GarrettCom Customer Support.  
5.1  
Before Calling for Assistance  
1.  
If difficulty is encountered when installing or operating the unit, refer back to the  
Installation Section of the applicable chapter of this manual. Also check to make sure  
that the various components of the network are interoperable.  
2.  
3.  
4.  
Check the cables and connectors to ensure that they have been properly connected and  
the cables/wires have not been crimped or in some way impaired during installation.  
(About 90% of network downtime can be attributed to wiring and connector  
problems.)  
Make sure that an AC power cord is properly attached to each Magnum DS880 10/100  
Dual Speed Stackable Hub unit. Be certain that each AC power cord is plugged into a  
functioning electrical outlet. Use the PWR LEDs to verify each unit is receiving  
power.  
If the problem is isolated to a network device other than the Magnum DS880 10/100  
Dual Speed Stackable Hub product, it is recommended that the problem device is  
replaced with a known good device. Verify whether or not the problem is corrected.  
If not, go to Step 5 below. If the problem is corrected, the Magnum DS880 10/100  
Dual Speed Stackable Hub and its associated cables are functioning properly.  
5.  
If the problem continues after completing Step 4 above, contact your supplier of the  
Magnum DS880 10/100 Dual Speed Stackable Hubs unit or if unknown, contact  
GarrettCom, Inc.by fax, phone or email ([email protected]) for assistance.  
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Magnum DS880 Dual-Speed Stackable Hubs  
Installation and User Guide (05/01)  
5.2  
When Calling for Assistance  
Please be prepared to provide the following information.  
A complete description of the problem, including the following points:  
a. The nature and duration of the problem;  
1.  
b. Situations when the problem occurs;  
c. The components involved in the problem;  
d. Any particular application that, when used, appears to create the problem;  
2.  
3.  
An accurate list of GarrettCom product model(s)involved, with serial number(s).  
Include the date(s) that you purchased the products from your supplier.  
It is useful to include other network equipment models and related hardware,  
including personal computers, workstations, terminals and printers; plus, the  
various network media types being used.  
4.  
A record of changes that have been made to your network configuration prior  
to the occurrence of the problem. Any changes to system administration  
procedures should all be noted in this record.  
5.3  
Return Material Authorization (RMA) Procedure  
All returns for repair must be accompanied by a Return Material Authorization  
(RMA) number. To obtain an RMA number, please use this URL -  
have the following information readily available:  
Name and phone number of your contact person.  
Name of your company / institution  
Your shipping address  
Product name  
Serial Number (or Invoice Number)  
Packing List Number (or Sales Order Number)  
Date of installation  
Failure symptoms, including a full description of the problem.  
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Magnum DS880 Dual-Speed Stackable Hubs  
Installation and User Guide (05/01)  
GarrettCom will carefully test and evaluate all returned products, will repair  
products that are under warranty at no charge, and will return the warranty-repaired units to  
the sender with shipping charges prepaid (see Warranty Information, Appendix A, for  
complete details). However, if the problem or condition causing the return cannot be  
duplicated by GarrettCom, the unit will be returned as:  
No Problem Found.  
GarrettCom reserves the right to charge for the testing of non-defective units  
under warranty. Testing and repair of product that is not under warranty will result in a  
customer (user) charge.  
5.4  
Shipping and Packaging Information  
Should you need to ship the unit back to GarrettCom, please follow these instructions:  
1. Package the unit carefully. It is recommended that you use the original container if  
available. Units should be wrapped in a "bubble-wrap" plastic sheet or bag for  
shipping protection. ( You may retain all connectors and this Installation Guide.)  
CAUTION Do not pack the unit in Styrofoam "popcorn" type packing material.  
:
This material may cause electro-static shock damage to the unit.  
2. Clearly mark the Return Material Authorization (RMA) number on the outside of the  
shipping container.  
3. GarrettCom is not responsible for your return shipping charges.  
4. Ship the package to:  
GarrettCom, Inc.  
47823 Westinghouse Dr.  
Fremont, CA 94539-7437  
Attn.: Customer Service  
APPENDIX A: WARRANTY INFORMATION  
GarrettCom, Inc. warrants its products to be free from defects in materials and  
workmanship for a period of three (3) years from the date of shipment by GarrettCom.  
During this warranty period, GarrettCom will repair or, at its option, replace  
components in the products that prove to be defective at no charge other than shipping  
and handling, provided that the product is returned pre-paid to GarrettCom.  
This warranty will not be effective if, in the opinion of GarrettCom, the product  
has been damaged by misuse, misapplication, or as a result of service or modification  
other than by GarrettCom.  
GarrettCom reserves the right to make a charge for handling and inspecting any  
product returned for warranty repair which turns out not to be faulty.  
Please complete the warranty card as this acts as a product registration, and mail  
it to GarrettCom within two weeks of your purchase.  
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Magnum DS880 Dual-Speed Stackable Hubs  
Installation and User Guide (05/01)  
APPENDIX B : Optional 48V DC Power Supply, Addendum  
B1.0  
SPECIFICATIONS - FOR DUAL-SPEED DS880 HUBS  
Power Supply (Internal 48 VDC Option)  
DC Power Connector: 3 terminals: -“, “GND”, “+”  
Input Voltage: 36 - 70 VDC (auto-ranging)  
Power Consumption: Model DS880: 12 watt typical, 20 watts max.  
With the exception of the power supply, all specifications and functions of  
Magnum DS880-48VDC models are identical to those listed in Section 1.  
B2.0  
48V DC SOURCE OPTION, THEORY OF OPERATION  
The 48VDC power option is designed using diodes inside on each DC power input  
line behind the two external power connection terminals, so that the power from an external  
POWER SWITCH  
source can only flow into the hub. This  
HUB  
SUPPLY  
allows the hub to operate only whenever  
+
A+  
A-  
FUSE  
-
DC power is correctly applied to the two  
inputs. It protects the hub from incorrect  
DC input connections. An incorrect  
CHASSIS  
GND  
GND  
polarity connection, for example, will neither effect the hub, nor its power supply internally, nor  
will it blow the fuse in the internal power supply.  
The power switch (included on premium-priced NEBS-certified units only) is used for  
powering the hub on and off when it is placed into or taken out of service.  
B3.0  
APPLICATIONS  
Magnum DS880 Dual-Speed Hubs are easily installed in a variety of applications  
where 48 VDC power is used as the primary power source. The 48VDC power configuration  
provides an Ethernet networking solution utilizing a special power supply in hubs with a proven  
track record.  
The solution is particularly useful in the telecommunication industry, where it is  
common for facilities to operate on 48VDC power. Such companies include regular and wireless  
telephone service providers, Internet Service Providers (ISPs) and other communication  
companies. In addition, many high availability equipment services, such as broadcasters,  
publishers, newspaper operations, brokerage firms and other facilities often use a battery backup  
system to maintain operations in the event of a power failure. It is also frequently used for  
computer system backup, management and operations monitoring equipment.  
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Magnum DS880 Dual-Speed Stackable Hubs  
B4.0 INSTALLATION  
This section describes the installation of the 48 VDC power source leads to the 48  
Installation and User Guide (05/01)  
VDC power terminal block on the Magnum DS880s. (see figure below).  
_
Figure B4.1: 48 VDC Terminal Block  
GND  
+
ON  
on Magnum DS880-48VDC  
OFF  
The 48 VDC terminal block on  
the Magnum DS880s is located on the rear  
of the unit and is equipped with three (3)  
screw-down lead posts. The leads are  
36-70VDC  
identified as negative (-), positive (+), and chassis ground (GND). The actual connection  
procedure is very straightforward. To avoid the confusion of -48V or +48V power supply,  
use a digital voltmeter to measure the output voltage and figure out the +VE Lead. The  
more +VE voltage terminal lead from the +48V or-48V power supply should be  
connected to the post leveled “+” and then the rest. Ensure that each lead is securely  
tightened.  
On the premium-priced NEBS-compliant Magnum DS880-48V models, an ON-OFF  
switch is included, located in the rear at the power input. This can be used in conjunction with  
power connections, and as a RESET for the hub’s electronics.  
B4.1  
UL Requirements  
1. Minimum 14 AWG cable for connection to a Centralized DC power source.  
2. Fastening torque of the lugs on the terminal block: 9 inch pound max.  
3. Centralized DC Power Source cable securement, use at least four cable ties to secure  
the cable to the rack at least 4 inches apart with the first one located within 6 inches  
of the terminal block.  
B5.0  
OPERATION  
Operation of the Magnum DS880s with the optional 48VDC power supply is identical  
to that of the standard AC-powered models.  
B6.0  
TROUBLESHOOTING  
Please refer to Section 5.0 for troubleshooting  
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