Black Box LMC5220A, Руководство по эксплуатации

Страница: 8 / 8

5 6
The following chart states the approximate Upstream and Downstream
speeds for Synchronous data rates at various distances.
Negotiation
The LAN Extender units will negotiate upwards to the highest or maxi-
mum obtainable synchronous speed. For example at a 2Km distance, the
Upstream and Downstream data rates will each be 10 Mbps. Negotiation
can take up to 30 seconds.
The VDSL Port
The data rate of the 10Base-S VDSL port on a LAN Extender (hereon
referred to as the VDSL port) depends on the distance in use. This includes
bandwidth limiting, via management, of the data rate for various distances.
The following graph illustrates the correlation between the distance and the
speed. The sum of the Upstream and Downstream data rates is fixed by the dis-
tance of the application. For example, if an application requires 1.5 Km, there
will be a maximum of 15 Mbps to distribute between the Upstream and
Downstream data rates. If Synchronous data rates are desired, configure 7.5
Mbps for Upstream and 7.5 Mbps for Downstream. Otherwise, speed can be
distributed in any combination between the Upstream and Downstream rates,
making data rates Asynchronous (12.5 Mbps and 2.1; 5 Mbps and 10 Mbps,
etc).
The following chart provides examples of Synchronous and Asynchronous data
rates at various distances.
25 Mbps
MAX
Speed
6.5 Mbps
500
m
10 Mbps
2
Km
MAX Distance
1.5
Km
15 Mbps
20 Mbps
1
Km
1.75
Km
Distance Data Rate Type
Upstream
Data Rate
Downstream
Data Rate
Approx. Total
of Data Rates
500 m Synchronous 12.5 Mbps 12.5 Mbps 25 Mbps
1.5 Km Asynchronous 2.1 Mbps 12.5 Mbps
15 Mbps
2 Km Asynchronous 2.1 Mbps 4.25 Mbps
6.5 Mbps
N O T E
Distances and speeds are approximate and depend on wiring qual-
ity and gauge. The actual Ethernet speeds are lower than the
speeds listed due to VDSL overhead (10% overhead). The distances
listed in the chart are less than or equal to the values listed.
Distance Data Rate Type
Upstream
Data Rate
Downstream
Data Rate
Approx. Total
of Data Rates
500 m Synchronous 12.5 Mbps 12.5 Mbps
25 Mbps
1 Km Synchronous 10 Mbps 10 Mbps 20 Mbps
1.5 Km Synchronous 7.5 Mbps 7.5 Mbps 15 Mbps
1.75 Km Synchronous 5 Mbps 5 Mbps 10 Mbps
2 Km Synchronous 3.25 Mbps 3.25 Mbps
6.5 Mbps