Lenovo Flex System Fabric CN4093, Application Manual

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CN4093 Application Guide for N/OS 8.4
Ingress VLAN Tagging
Tagging can be enabled on an ingress port. When a packet is received on an ingress
port, and if ingress tagging is enabled on the port, a VLAN tag with the port PVID
is inserted into the packet as the outer VLAN tag. Depending on the egress port
setting (tagged or untagged), the outer tag of the packet is retained or removed
when it leaves the egress port.
Ingress VLAN tagging is used to tunnel packets through a public domain without
altering the original 802.1Q status.
When ingress tagging is enabled on a port, all packets, whether untagged or
tagged, will be tagged again. As shown in Figure 7 , when tagging is enabled on the
egress port, the outer tag of the packet is retained when it leaves the egress port. If
tagging is disabled on the egress port, the outer tag of the packet is removed when
it leaves the egress port.
Figure 7.
802.1Q tagging (after ingress tagging assignment)
By default, ingress tagging is disabled. To enable ingress tagging on a port, use the
following commands:
Limitations
Ingress tagging cannot be configured with the following features/configurations:
 vNIC ports
 VMready ports
 UFP ports
 Management ports
CN 4093(config)# interface port
<number>
CN 4093(config-if)# tagpvid-ingress
Port 6
DA SA Data CRC
Port 7 Port 8
Port 1
Port 4 Port 5
Port 2 Port 3
802.1Q Switch
PVID = 2
Untagged packet
Untagged member
of VLAN 2
Tagged member
of VLAN 2
Before
DA SA Data CRC* Tag DA SA Data CRC* Tag
After
DA SA Data CRC
Port 6 Port 7 Port 8
Port 1
Port 4 Port 5
Port 2 Port 3
802.1Q Switch
PVID = 2
Tagged packet
Untagged member
of VLAN 2
Tagged member
of VLAN 2
Before
DA SA Data CRC* Tag 1 DA SA Data CRC* Tag 1
After
DA SA Data CRC* Tag 1
Tag 2 Tag 2
DA SA Data CRC* Tag 1
Untagged packet received on ingress port
Tagged packet received on ingress port