NWK954 Datasheet PDF - Mitel Networks
| Part Number | NWK954 | |
| Description | QUAD FAST ETHERNET REPEATER | |
| Manufacturers | Mitel Networks | |
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Supersedes January 1998 version, DS4842 - 1.1
The NWK954 is a fully integrated, unmanaged, 4-port Fast
Ethernet Repeater conforming to the IEEE 802.3 100BASE-TX
Standard. The device integrates the 802.3 Repeater functions
with four 100BASE-TX PHY modules, enabling direct connection
to the isolation transformers with no additional PHY components.
It has built-in LED drivers for display of port activity and
network utilization. There is a local expansion port which allows
up to six NWK954s to be cascaded to form a 24-port repeater
with no additional components.
With the addition of simple backplane driver/receivers, up to
eight 24-port repeaters can be stacked.
The NWK954 is supplied in a 128-pin PQFP and interfaces
to the twisted pair media through 1:1 isolation transformers.
ORDERING INFORMATION
NWK954D/CG/GH1N
NWK954
QUAD FAST ETHERNET REPEATER
PRELIMINARY INFORMATION
DS4842-2.1 April 1998
FEATURES
s Compliant with IEEE 802.3 100BASE-TX Repeater
Unit Specification
s Incorporates four IEEE 802.3 Compliant 100BASE-TX
Ports
s Local Expansion Port for Cascading to 24 Ports
s Stackable Backplane for Expansion up to 192 Ports
s Link/Activity LED and Receive Error LED for each Port
s Collision LED
s Five LED Network Utilization Display
s Base Line Wander Correction
s Power Saving on Unused Ports
s Driven from a Single 25MHz Clock
s Single 5V supply
s Low Power CMOS Technology
s 128-pin PQFP package
BACKPLANE CONTROLS
BACKPLANE BUFFERS
OSCILLATOR
CLOCK DRIVERS
LOCAL EXPANSION BUS
NWK954
NWK954
NWK954
QUAD
MAGNETICS
QUAD RJ45
QUAD
MAGNETICS
QUAD
MAGNETICS
NWK954
QUAD
MAGNETICS
Fig. 1 System block diagram
NWK954
QUAD
MAGNETICS
NWK954
QUAD
MAGNETICS
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Basic Repeater Function
The Repeater Controller monitors activity on the 4 twisted
pair ports and on the Expansion Port. When a packet is received
on one of the twisted pair ports it is forwarded to the other 3
twisted pair ports and to the Expansion Port. When a packet is
received on the Expansion Port it is forwarded to all 4 twisted
pair ports. When receive activity is detected on 2 or more ports
the Repeater Controller will send the jam signal to all twisted
pair ports for the duration of all activity associated with the
collision event.
Jabber Protection
The Repeater Controller provides receive jabber protection
to ensure that the network is not disrupted by excessively long
data streams. If a received data stream exceeds 65,536 bit times
then the receiving port will be shutdown. In the shutdown state
data received on the faulty port is ignored and packets received
from other ports are not transmitted to the faulty port. A port will
recover from the shutdown state when the incoming data stream
ends or if the device is reset.
Auto-Partition Function
The auto-partition function prevents faulty behaviour on a
network segment from disrupting the entire network. The
Repeater Controller counts consecutive collisions on each port
and will partition a port that causes more than 60 consecutive
collisions. In the partitioned state, packets received on the faulty
port will be ignored but packets received from other ports will
continue to be transmitted to the faulty port. The port will recover
from the partitioned state when valid activity is detected on the
port or if the device is reset.
Carrier Integrity Monitor
The Repeater Controller detects false carrier events on all
ports. A false carrier is defined as receive activity that does not
commence with the correct start-of-packet sequence. When a
false carrier event is detected, the Repeater Controller will
transmit the jam signal on all ports for the duration of the false
carrier event provided it does not exceed 450-500 bit times.
After this time the port will be isolated and the jam signal will
cease. The NWK954 will also isolate a port that suffers 2
successive false carrier events. In the isolated state, packets
received from the faulty port are ignored and packets received
from other ports are not transmitted to the faulty port. A port will
recover from the isolated state when a valid inter-packet gap is
detected and is followed by either a valid packet exceeding 450-
500 bit times or by an idle sequence exceeding 33000 (±25%)
bit times.
Expansion Port
The Expansion Port allows up to 6 NWK954s to be cascaded.
This allows a 24-port hub to be built with no additional external
components. The Expansion Port includes a 5-bit parallel
bidirectional data bus (IRD) which carries unscrambled symbol data
and a 25MHz sampling clock (BPCLK). Each NWK954 indicates
receive activity on any of its 4 twisted pair ports by asserting the
local activity output (LACTOUT_N). The LACTOUT_N signals from
each NWK954 connect to the local activity inputs (LACTIN_N) of all
the other cascaded NWK954s.
When a collision occurs between 2 twisted pair ports on an
NWK954, the event is communicated to other cascaded NWK954s
by asserting the collision signal (BPCOL_N). This instructs all
cascaded NWK954s to transmit the jam signal for the duration of
the collision event. BPCOL_N is also asserted when a collision occurs
between 2 twisted pair ports on different NWK954s.
Backplane
The Expansion Port allows hubs to be stacked via a backplane
bus. This requires the addition of some simple external driver/
receivers. The functional requirement for these components is
illustrated in Fig. 6. Contact Mitel for full details of recommended
components.
NWK954
BPACTIN_ N [7:1]
5
LACTIN_N [5:1]
LACTOUT_N
BPCOLIN_N TXCLKIN
BPCOL_N
BPCLK
5
IRD [4:0]
BPACTIN_ N [7:1]
5
LACTIN_N [5:1]
LACTOUT_N
BPCOLIN_N TXCLKIN
BPCOL_N
BPCLK
5
IRD [4:0]
BPACTIN_ N [7:1]
5
LACTIN_N [5:1]
LACTOUT_N
BPCOLIN_N TXCLKIN
BPCOL_N
BPCLK
5
IRD [4:0]
BPACTIN_ N [7:1]
5
LACTIN_N [5:1]
LACTOUT_N
BPCOLIN_N TXCLKIN
BPCOL_N
BPCLK
5
IRD [4:0]
BPACTIN_ N [7:1]
5
LACTIN_N [5:1]
LACTOUT_N
BPCOLIN_N TXCLKIN
BPCOL_N
BPCLK
5
IRD [4:0]
BPACTIN_ N [7:1]
5
LACTIN_N [5:1]
LACTOUT_N
BPCOLIN_N TXCLKIN
BPCOL_N
BPCLK
5
IRD [4:0]
CLOCK
DRIVER
25MHz
OSCILLATOR
Fig. 5 Cascaded NWK954s
5
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| Information | Total 17 Pages | |
| Link URL | [ Copy URL to Clipboard ] | |
| Download | [ NWK954.PDF Datasheet ] | |
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| Part Number | Description | MFRS |
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