Specifications

W5-Ethernet-Manual.doc
Version 2.0-01
Watson 5 Ethernet
Operating Manual
Revision: 2006-04-27 3-11
The Ethernet bridge supports the following modes
1) VLAN bridging. Layer 2 VLANs are used to control the traffic. For an Ethernet packet to be sent
from one port to another both ports must be configured to be in the same VLAN. This bridging
mode allows to connect Ethernet user interfaces can be switched to DSL interfaces and vice
versa. It is also possible to switch packets from several DSL interfaces to one Ethernet inter-
face (concentration), to switch packets from an Ethernet or DSL interface to the Management
Processor interface MGMT3 (used for inband management) or to switch packets from DSL to
DSL interface.
2) Transparent bridging. In this mode there is a fixed association between DSL and Ethernet
bridge ports:
Ethernet Bridge
ETH1
ETH2
ETH3
ETH4
DSL1
DSL2
DSL3
DSL4
Ethernet Ports
DSL Ports
Figure 3-5: Transparent bridging
Transparent bridging is similar to the VLAN transparency provided by the Watson 5 Ethernet
tabletop modem, cf. 3.3.2. Transparent bridging lacks the flexibility of VLAN bridging, and in-
band management or linear networks are not supported in this mode. The advantage of trans-
parent bridging is that it is not required to configure any VLAN tags on the bridge, any VID re-
ceived on an Ethernet port will be relayed to the corresponding DSL port and vice versa.
Note that the association between Ethernet and DSL ports is independent of the currently con-
figured multipair mode of the DSL ports. If for example all four DSL wire pairs are combined to
a single DSL span (DSL1) then Ethernet port ETH1 will be associated with DSL port DSL1
while ports ETH2 .. ETH4 and DSL2 .. DSL4 do not carry any traffic at all.
3) Transparent bridging with inband management. This mode is equivalent to the Transparent
bridging mode but allows inband management through the DSL links, cf. 3.5.5.
The bridging modes are controlled by the monitor command BRIDGEMODE.
3.2.3 VLANs
The Watson 5 Ethernet plugin supports VLAN functions according to IEEE 802.1q. Each of the
Ethernet bridge ports (ETH1 .. ETH4, DSL1 .. DSL4, MGMT3) can be member of one or several
VLANs. The maximum number of VLANs is 64. Each VLAN has a VLAN Identifier (VID) between 1
and 4094.
Upon reception of an Ethernet packet at a port its VID is checked against the VIDs of all VLANs this
port is a member of. Packets that do not carry one of these VIDs will be discarded.
For untagged packets the default VID for the port is used to determine VLAN membership.
Packets are only forwarded to ports that are a member of the VLAN of this packet.
Upon transmission the packet will be tagged with the VLAN tag originally received. If the packet
was untagged then the default tag of the receiving port is added to the packet. The port can also be
configured to send the packets untagged.