Ingress Vlan Tagging - Lenovo Flex System Fabric CN4093 Application Manual

PVID = 2
Untagged member

Ingress VLAN Tagging

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CN4093 Application Guide for N/OS 8.2
Figure 6. 802.1Q tagging (after 802.1Q tag assignment)
Port 1 Port 2
802.1Q Switch
Port 6 Port 7
CRC* (*Recalculated)
of VLAN 2
Data
SA
DA
Note: Set the configuration to factory default
(CN4093(config)# boot configuration­block factory) to reset all
non-management ports to VLAN 1.
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
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.
Tagged member
Port 3
of VLAN 2
CRC Data
Port 8
Outgoing
untagged packet
changed Key
(tag removed)
Priority
CFI
VID
7, when tagging is enabled on the
Tag SA DA
8100 Priority CFI VID = 2
16 bits 3 bits 1 bit 12 bits
After
- User_priority
- Canonical format indicator
- VLAN identifier