ZyXEL Communications MSC1000G User Manual page 49

Chapter 1 Getting to Know Your MSC
example, it is cheaper to use multiple lower-speed links than to under-utilize a high-speed, but
more costly, single-port link.
IEEE 802.1Q Tagged VLAN
Your MSC uses the IEEE 802.1Q Tagged VLAN (Virtual Local Area Network), which allows your
device to deliver tagged/untagged frames to and from its ports.
Subnet Based VLAN
Subnet based VLAN allows you to group traffic into logical VLANs based on the source IP subnet you
specify. When a frame is received on a port, the MSC checks if a tag is added already and the IP
subnet it came from. The untagged packets from the same IP subnet are then placed in the same
subnet based VLAN. One advantage of using subnet based VLANs is that priority can be assigned to
traffic from the same IP subnet.
XVLAN (VLAN translation)
XVLAN (VLAN translation) changes the VLAN tag on traffic received from a subscriber port to
another VLAN ID for the service provider's network. This makes it easier to deploy customer-
specific VLANs because all the CPE devices can use the same VLAN configuration. You only need to
configure XVLAN on the DSLAM to use unique VLAN IDs for each subscriber's traffic. XVLAN on the
VLC13XXGs also supports translating single-tagged frames to double-tagged frames.
Multicast VLAN
Multicast VLAN is designed for applications (such as Media-on-Demand (MoD)) using multicast
traffic across an Ethernet ring-based service provider network. Multicast VLAN allows one single
multicast VLAN to be shared among different subscriber VLANs on the network. This improves
bandwidth utilization by reducing multicast traffic in the subscriber VLANs and simplifies multicast
group management.
Transparent LAN Service (TLS)
Use TLS (also known as VLAN stacking) to add an outer VLAN tag to the inner IEEE 802.1Q tagged
frames that enter the network. By tagging the tagged frames ("double-tagged" frames), the service
provider can manage up to 4,094 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.
VDSL Double-Tag 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). The line card drops any tagged frames it receives from a subscriber.
Double-Tag PVC (DTPVC)
DTPVCs (Double-Tag Permanent Virtual Circuits) add double VLAN tags to untagged frames received
from a DSL subscriber on the specified PVC. These double VLAN tags consist of an inner c-tag
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Management Switch Card User's Guide