User's Manual

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DA
(6B)
SA
(6B)
ETYPE(8100)
(2B)
SPVLAN Tag
(2B)
ETYPE
(8100)
(2B)
CVLAN Tag
(2B)
ETYPE
(2B)
DATA
(0~1500B)
FCS
(4B)
Figure 6 Structure of a packet going into PE1
3) In the backbone network, packets are transmitted along the port of trunk VLAN 10. The tag of the
private network is kept in transparent state until these packets reach PE2.
4) PE2 discovers that the port where it connects CE2 is the access port of VLAN 10, removes the tag
header of VLAN 10 according to 802.1Q, resumes the initial packets of users, and transmit the
initial packets to CE2, as shown in figure 7.
DA
(6B)
SA
(6B)
ETYPE(8100)
(2B)
VLAN TAG
(2B)
ETYPE
(2B)
DATA
(0~1500B)
FCS
(4B)
Figure 7 Structure of a packet from PE2
Seen from the forwarding flow, Dot1Q Tunnel is very concise for the signaling is not required to maintain
the establishment of the tunnel, which can be realized through static configuration.
As to the typical configuration figure of Dot1Q Tunnel, products of different models are configured as
follows when they run as PE (PE1 configuration is same to PE2).
1) Dot1Q Tunnel Configuration of the switch
Switch_config#dot1q-tunnel
Switch_config_g0/1#switchport pvid 10
Switch_config_g0/2#switchport mode trunk
Switch_config_g0/2#switchport trunk vlan-untagged 1-9,11-4094