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
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
Expansion Port
The Expansion Port allows up to 6 NWK954s to be cascaded. This allows a
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