ZyXEL Communications P-873HNU-51B, Руководство пользователя

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Chapter 6 Broadband
P-873HNU(P)-51B User’s Guide
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6.3 The DSL Screen
If the DSLAM of your ISP supports DSL bonding, you can connect the two DSL ports on the VDSL
Router to two separate telephone jacks and enable the bonding feature in the DSL screen.
DSL signals have distance limitations. VDSL2 (profile 17a) supports greater speed but offer shorter
distances (within 3000 ft). The farther away the subscribers are from the DSLAM, the slower the
speed. VDSL (profile 12a) provides longer distance range (over 3000 ft) but at lower speeds. DSL
bonding allows subscribers to use data streams spread over two DSL lines in order to (almost)
double the speed at longer distances. You may choose to use DSL bonding if the DSLAM supports it
and there are two DSL lines to the DSLAM.
The total available bandwidth for the subscriber then becomes the sum of the bandwidth available
for each of the subscriber’s line connections. The data rate depends on the DSL type, its standard/
profile, and the standard/profile that the DSLAM supports. The table below shows the transmission
data rate for single DSL line and DSL bonding.
Table 9
Comparison Table for Single DSL line and DSL Bonding
For a single VDSL line, the profile is 17a, which provides a maximum data rate of 100/60 Mbps
(downstream/upstream). If VDSL bonding is used, the supported profile is 12a, which provides a
maximum data rate of 50/25 Mbps for each VDSL line. The ideal total data rate for the bonded
connection is 100/50 Mbps.
For a single ADSL line, the standard with the highest data rate supported is ADSL2+, which
provides 25/1 Mbps data rate. When ADSL bonding is used, the data rate doubles to 50/2 Mbps.
In addition, DSL bonding supports ADSL bonding fallback. If a VDSL connection cannot be
established, the VDSL Router tries to use ADSL. If the VDSL connection is re-established, the VDSL
Router automatically switches back to VDSL. You must enable DSL bonding in order to use ADSL
fallback.
Click Broadband > DSL to display the following screen.
ITEM VDSL2 VDSL BONDING ADSL2+
ADSL(2+)
BONDING
PROFILE/
STANDARD
G993.2 Profile 17a G993.2 Profile 12a G.992.5 G.992.5
MAX.
DOWNSTREAM/
UPSTREAM
100/60 Mbps 50/25 x 2 = 100/50
Mbps
25/1 Mbps 25/1 x 2 = 50/2
Mbps
DISTANCE
within 3000 ft over 3000 ft over 5000 ft 5000 to 7000 ft