LB9905A BLACK BOX, LB9905A Datasheet - Page 3

• Manufacturer Part Number: LB9905A
• Description: Ethernet Switch
• Manufacturer: BLACK BOX

Specifications of LB9905A

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09/30/2010
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technically speaking
board. The front side of the chassis has six RJ-45 twisted-pair
ports and two 100-Mbps, full-duplex fiber ports, which operate
in full-duplex mode only to provide higher bandwidth and longer
distances on fiber.
has an architecture that supports a dual- speed switching
environment. These copper ports, equipped with autonegotiation
capability, operate in full or half-duplex and sense for speed, per
the IEEE 802.3u standard.
made on the copper ports and each time a link is enabled. When
the connected device is 10 Mbps, the Hardened Ethernet Switch
obeys all the rules of 10-Mbps Ethernet configurations. 10-Mbps
users can share a 10-Mbps traffic domain and can communicate
with 100-Mbps users as well as users in the 100-Mbps domain.
Similarly, 100-Mbps traffic adheres to 100-Mbps Ethernet rules
and can communicate with the 10-Mbps domain, too.
domain, providing a high-bandwidth backbone connection while
supporting longer distances, up to 20 km (12.4 mi.) on models
with single-mode connections. You can also daisychain the
switches in a string application to create an Ethernet network
that’s hundreds of kilometers long.
following three types of media: 100BASE-TX, 10BASE-T, and
100BASE-FX.
Packet filtering/forwarding.
the switch either filters or forwards it.
same port segment are filtered and constrained to one port so the
rest of the network doesn’t have to process them. A packet that
has a destination address on another port segment is forwarded
to the appropriate port. But packets that you need for maintaining
the network’s operation—such as occasional multicast packets—
are forwarded to all ports.
Frame buffering.
packet) is loaded into the switch’s memory and inspected before
forwarding can occur. This way, all forwarded frames are of a valid
length and have the correct CRC.
The Hardened Ethernet Switch chassis houses one main PC
With the its six 10/100 RJ-45 switched ports, the switch
Autonegotiation occurs when an RJ-45 cable connection is
The fiber optic ports are switched ports and perform as a
You can connect the Hardened Ethernet Switches to the
Each time a packet arrives on one of the switched ports,
Packets with source and destination addresses on the
Because it’s a store-and-forward switch, each frame (or
available bandwidth can be used for valid information during
peak traffic times.
space from a 1-MB memory pool to minimize the possibility of
dropping frames on congested ports. This ensures that heavily
used ports receive very large buffer space for packet storage.
Allocation of this sort enables the switch to apply its resources
to all traffic loads, even when the traffic activity is unbalanced
across its ports.
per port and in aggregate density, the switch continually adapts
internally to provide maximum network performance with the
least dropped packets.
Flow control.
queue is losing space. It does this by sending industry-standard
(full-duplex only) ”pause” packets to the devices sending packets,
thereby temporarily stopping incoming traffic until existing traffic
can catch up without dropping packets. This flow control process
is transparent to the user.
operating in at half-duplex, the switch can prevent more frames
from entering a full buffer queue by forcing a collision signal on
all receiving RJ-45 half-duplex ports.
of 16K node addresses, is suitable for use in large networks.
When nodes are added or removed or moved from one segment
to another, the self-learning switch automatically keeps up with
node locations. In addition, its address-aging algorithm causes
least-used addresses to drop out in favor of ones that you use
frequently.
Monitor activity via LEDs.
software configuration during installation or for maintenance.
indicators on the unit’s top cover. The LEDs conveniently indicate
operating status of all ports. There’s a power ”on” (PWR)
indicator, and a self-test at power up. For each RJ-45, there are
link/activity (LK/ACT) LEDs indicating traffic and speed, and full-/
half-duplex indicators (F/H). The fiber ports have link/activity
(LK/ACT) indicators.
By eliminating the propagation of bad packets, all of the
The Hardened Ethernet Switches dynamically allocate buffer
Because network traffic constantly varies in packet density
Flow control kicks in when the switch detects that its buffer
You also get a collision-based flow-control mechanism. When
The Hardened Ethernet Switch, with an address table capacity
Plug-and-play, the Hardened Ethernet Switch requires no
To monitor activity on the switch, you simply view the LED
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