Zyxel VES-1616FE-55A [102/318] Dsl standards overview

Zyxel VES-1616FE-55A [102/318] Dsl standards overview
Chapter 13 xDSL Port Setup
VES-1616FE-55A User’s Guide
102
13.5 DSL Standards Overview
These are the DSL standards and rates that the VES-1616FE-55A supports at the time of
writing. The actual transfer rates will vary depending on what the subscribers device supports,
the line conditions and the connection distance.
13.6 Downstream and Upstream
Downstream refers to traffic going out from the VES-1616FE-55A to the subscribers DSL
modem or router. Upstream refers to traffic coming into the VES-1616FE-55A from the
subscribers DSL modem or router.
13.7 Configured Versus Actual Rate
You configure the maximum rate of an individual DSL port by modifying its profile (see
Chapter 14 on page 115) or assigning the port to a different profile (see Section 13.9.1 on page
104). However, due to noise and other factors on the line, the actual rate may not reach the
maximum that you specify.
Even though you can specify arbitrary numbers using the Edit Profile screen, the actual rate is
always a multiple of 32 Kbps. If you enter a rate that is not a multiple of 32 Kbps, the actual
rate will be the next lower multiple of 32Kbps. For instance, if you specify 60 Kbps for a port,
the actual rate for that port will not exceed 32 Kbps, and if you specify 66 Kbps, the actual rate
will not be over 64Kbps.
Regardless of a profile’s configured upstream and downstream rates, the VES-1616FE-55A
automatically limits the actual rates for each individual port to the maximum speeds supported
by the port’s DSL operational mode. For example, if you configure a profile with a maximum
downstream rate of 25000 Kbps, and apply it to a port set to use G.dmt, the VES-1616FE-55A
automatically uses a maximum downstream rate of 8160 Kbps. This means that if you
configure a profile with very high rates, you can still use it with any port. See Table 22 on page
102 for a list of the maximum rates supported by the different xDSL standards.
13.8 Default Settings
The default profile always exists and all of the DSL ports use the default profile settings when
the VES-1616FE-55A is shipped. The default profile's name is set to
DEFVAL_MAX.
Table 22 DSL Standards Maximum Transfer Rates
STANDARD MAXIMUM DOWNSTREAM MAXIMUM UPSTREAM
8a/b/c/d 85 Mbps 18 Mbps
12a/b 85 Mbps 50 Mbps
17a 100 Mbps 50 Mbps
ADSL2+ 24 Mbps 1 Mbps

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