Edge-Core ECS3510-10PD, Management Manual

Page: 212 / 1494

C
HAPTER
6
| VLAN Configuration
IEEE 802.1Q Tunneling
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egress process transmits the packet. Packets entering a QinQ tunnel port
are processed in the following manner:
1.
An SPVLAN tag is added to all outbound packets on the SPVLAN
interface, no matter how many tags they already have. The switch
constructs and inserts the outer tag (SPVLAN) into the packet based on
the default VLAN ID and Tag Protocol Identifier (TPID, that is, the
ether-type of the tag), unless otherwise defined as described under
"Creating CVLAN to SPVLAN Mapping Entries" on page 215 . The priority
of the inner tag is copied to the outer tag if it is a tagged or priority
tagged packet.
2.
After successful source and destination lookup, the ingress process
sends the packet to the switching process with two tags. If the
incoming packet is untagged, the outer tag is an SPVLAN tag, and the
inner tag is a dummy tag (8100 0000). If the incoming packet is
tagged, the outer tag is an SPVLAN tag, and the inner tag is a CVLAN
tag.
3.
After packet classification through the switching process, the packet is
written to memory with one tag (an outer tag) or with two tags (both
an outer tag and inner tag).
4.
The switch sends the packet to the proper egress port.
5.
If the egress port is an untagged member of the SPVLAN, the outer tag
will be stripped. If it is a tagged member, the outgoing packets will
have two tags.
Layer 2 Flow for Packets Coming into a Tunnel Uplink Port
An uplink port receives one of the following packets:
◆
Untagged
◆
One tag (CVLAN or SPVLAN)
◆
Double tag (CVLAN + SPVLAN)
The ingress process does source and destination lookups. If both lookups
are successful, the ingress process writes the packet to memory. Then the
egress process transmits the packet. Packets entering a QinQ uplink port
are processed in the following manner:
1.
If incoming packets are untagged, the PVID VLAN native tag is added.
2.
If the ether-type of an incoming packet (single or double tagged) is not
equal to the TPID of the uplink port, the VLAN tag is determined to be a
Customer VLAN (CVLAN) tag. The uplink port’s PVID VLAN native tag is
added to the packet. This outer tag is used for learning and switching
packets within the service provider’s network. The TPID must be
configured on a per port basis, and the verification cannot be disabled.
3.
If the ether-type of an incoming packet (single or double tagged) is
equal to the TPID of the uplink port, no new VLAN tag is added. If the