Dot1Q-Tunnel Configuration Task List - Digitalchina Networks DCS-3950 series Manual

As shown in Fig 9-3, after being enabled on the user port, dot1q-tunnel assigns each
user a SPVLAN identification (SPVID). Here the identification of user is 3. Same SPVID
should be assigned for the same network user on different PEs. When packet reaches
PE1 from CE1, it carries the VLAN tag 200-300 of the user internal network. Since the
dot1q-tunnel function is enabled, the user port on PE1 will add on the packet another
VLAN tag, of which the ID is the SPVID assigned to the user. Afterwards, the packet will
only be transmitted in VLAN3 when traveling in the ISP internet network while carrying two
VLAN tags (the inner tag is added when entering PE1, and the outer is SPVID), whereas
the VLAN information of the user network is open to the provider network. When the
packet reaches PE2 and before being forwarded to CE2 from the client port on PE2, the
outer VLAN tag is removed, and then the packet CE2 receives is absolutely identical to
the one sent by CE1. For the user, the role the operator network plays between PE1 and
PE2,is to provide a reliable layer-2 link.
The technology of Dot1q-tuunel provides the ISP internet the ability of supporting
many client VLANs by only one VLAN of theirselves. Both the ISP internet and the clients
can configure their own VLAN independently.
It is obvious that, the dot1q-tunnel function has got following characteristics:
Applicable through simple static configuration, no complex configuration or
maintenance to be needed.
Operators will only have to assign one SPVID for each user, which increases
the number of concurrent supportable users; while the users has got the
ultimate freedom in selecting and managing the VLAN IDs (select within
1~4096 at users' will).
The user network is considerably independent. When the ISP internet is
upgrading their network, the user networks do not have to change their
original configuration.
Detailed description on the application and configuration of dot1q-tunnel of DCS-3950
series will be provided in this section

9.3.2 Dot1q-Tunnel Configuration Task List

DCS-3950 series Ethernet switch manual
Figure 9-3Typical VLAN Application Topology
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