User's Manual

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 Supports the inter-translation between customer VLAN and SPVLAN on the downlink port,
including translation in Flat mode and in QinQ mode.
 Supports the configuration of the uplink port.
 Supports changeable TPID.
31.2.2 Dot1Q Tunnel Realization Mode
There are two modes to realize Dot1Q Tunnel: port-based Dot1Q Tunnel and Dot1Q Tunnel based
on inner CVLAN tag classification.
1) Port-based Dot1Q Tunnel:
When a port of this device receives packets, no matter whether packets have the VLAN tag, the
switch will add the VLAN tag of the default VLAN on this port to these packets. Thus, if a received
packet has a VLAN tag, the packet become a packet with double tags; if a received packet is
untagged, this packet will be added a default VLAN tag of this port.
The packet with a single VLAN tag has the following structure, as shown in table 1:
DA
(6B)
SA
(6B)
ETYPE(8100)
(2B)
VLAN TAG
(2B)
ETYPE
(2B)
DATA
(0~1500B)
FCS
(4B)
Table 1 Packet with a single VLAN tag
The packet with double VLAN tags has the following structure, as shown in table 2:
DA
(6B)
SA
(6B)
ETYPE(8100)
(2B)
SPVLAN
Tag
(2B)
ETYPE
(8100)
(2B)
CVLAN Tag
(2B)
ETYPE
(2B)
DATA
(0~1500B)
FCS
(4B)
Table 2 Packet with double VLAN tags
2) Dot1Q Tunnel based on the inner CVLAN Tag:
The service is distributed according to the CVLAN ID zone of the inner CVLAN tag of Dot1Q Tunnel.
The CVLAN zone can be translated into SPVLAN ID and there are two translation modes: Flat VLAN
translation and QinQ VLAN translation. In QinQ VLAN translation mode, when a same user uses
different services by using different CVLAN IDs, the services can be distributed according to CVLAN ID.
For example, the CVLAN ID of bandwidth service ranges between 101 and 200; the CVLAN ID of VOIP
service ranges between 201～300; and the CVLAN ID of IPTV service ranges between 301～400. When
PE device receives the user data, set SPVLAN Tag with ID as 1000 for the bandwidth service; set
SPVLAN Tag with ID as 2000 for the VOIP service; set SPVLAN Tag with ID as 3000 for IPTV. The
difference of the Flat VLAN translation mode and the QinQ VLAN translation mode is that in the flat
VLAN translation mode the SPVLAN tag is not on the out-layer of the CVLAN tag, but replaces the
CVLAN tag directly.
31.2.3 Modifying Attributes Through TPID Value
The structure of the Tag packet of Ethernet frame that is defined by the IEEE 802.1Q protocol is
shown below:
TPID
User Priority
CFI VLAN ID