Ingress Vlan Tagging - Lenovo RackSwitch G8264 Application Manual

Ingress VLAN Tagging

© Copyright Lenovo 2016
Figure 6. 802.1Q tagging (after 802.1Q tag assignment)
PVID = 2
Port 1
802.1Q Switch
Port 6
Untagged member
of VLAN 2
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.
Port 2 Port 3
CRC
Port 7 Port 8
CRC* (*Recalculated)
Data
Outgoing
SA
untagged packet
changed
DA
(tag removed)
Tagged member
of VLAN 2
Data Tag SA DA
8100 Priority CFI
16 bits 3 bits 1 bit
After
Key
Priority - User_priority
CFI - Canonical format indicator
VID - VLAN identifier
7, when tagging is enabled on the
Chapter 9: VLANs
VID = 2
12 bits
BS45014A
159