Magnum DS880 Dual-Speed Stackable Hubs Installation and User Guide (05/01)
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Product Description - General
Magnum DS880 Dual-Speed hubs have eight RJ-45 ports, each 10/100Mb auto-
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.
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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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DS880A
