ZyXEL Communications MSC1000G Series, User Manual

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Chapter 9 Subscriber Port Setup Screens
Management Switch Card User’s Guide
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9.2.14 DT VLAN
DT VLAN (Double-Tag VLAN) adds two VLAN tags to untagged frames received on a VDSL port.
These two VLAN tags consist of an inner c-tag (customer tag) and an outer s-tag (service provider
tag).
Double-tag VLAN can be used for applications such as distinguishing between multiple service
providers or distinguishing multiple customers VLANs, even those with the same customer VLAN ID.
The service provider can manage up to 4,094 service provider VLAN groups with each group
containing up to 4,094 customer VLANs. This allows a service provider to provide different services,
based on specific VLANs, for many different customers.
The line card drops any tagged frames received on the VDSL port. See Section 9.2.12 on page 209
for more on double-tagged VLAN.
9.3 Downstream and Upstream
Downstream refers to traffic going out from the line card to the subscriber's DSL modem or router.
Upstream refers to traffic coming into the line card from the subscriber's DSL modem or router.
9.4 DSL Profiles
A DSL profile is a table that contains a list of pre-configured DSL settings. Each DSL port has one
(and only one) profile assigned to it at any given time. You can configure multiple profiles, including
profiles for troubleshooting. Profiles allow you to configure DSL ports efficiently. You can configure
many DSL ports with the same profile, thus removing the need to configure the settings of each
DSL port one-by-one. You can also change an individual DSL port’s settings by assigning it a
different profile.
For example, you could set up different profiles for different kinds of accounts (for example,
economy, standard and premium). Assign the appropriate profile to an DSL port and it takes care of
a large part of the port’s configuration. You still get to individually enable or disable each port and
configure port specific settings. See the chapter on profiles for how to configure DSL profiles.
9.5 Alarm Profiles
Alarm profiles define DSL port alarm thresholds. The system sends an alarm trap and generates a
syslog entry when the thresholds of the alarm profile are exceeded. See the chapter on profiles for
how to configure alarm profiles.
Table 93
802.1Q Frame
DA Destination Address Priority 802.1p Priority
SA Source Address Len/Etype Length and type of Ethernet frame
(SP)TPID (Service Provider) Tag Protocol IDentifier Data Frame data
VID VLAN ID FCS Frame Check Sequence