
Figure 4-7
Formats of Ethernet frames
6 bytes
6 bytes
4 bytes
2 bytes
4 bytes
Destination
MAC Address
VLAN
Length/Type
Data
FCS Check
Character
6 bytes
6 bytes
4 bytes
2 bytes
4 bytes
C-VLAN
S-VLAN
4 bytes
Variable
length
6 bytes
6 bytes
4 bytes
2 bytes
4 bytes
Format of the frame with
one C-VLAN tag
Source MAC
Address
Variable
length
Destination
MAC Address
C-VLAN
Length/Type
Data
FCS Check
Character
Source MAC
Address
Destination
MAC Address
Length/Type
Data
FCS Check
Character
Source MAC
Address
Variable
length
Format of the frame with
one S-VLAN tag nested
with one C-VLAN tag
802.1q frame format
The length of the data field is variable. maximum length of the data field depends on the
maximum frame length that the ports of the equipment support.
The four-byte S-VLAN or C-VLAN field is divided into two sub-fields: the tag protocol ID
(TPID) and the tag control Information (TCI).
Both the TPID and TCI consist of two bytes. See
Figure 4-8
Positions of the TPID and TCI in the frame structure
C-VLAN
S-VLAN
2
2
2
2
TPID
TPID
TCI
TCI
6 bytes
6 bytes
2 bytes
4 bytes
Destination
MAC Address
Length/Type
Data
FCS Check
Character
Source MAC
Address
bytes
2
bytes
bytes
bytes
Variable
length
l
TPID structure
The TPID consists of two bytes and indicates the VLAN tag type. TPID of the C-VLAN is
always 0x8100 whereas the TPID of the S-VLAN can be customized. Refer to
Table 4-4
Tag types defined by using the TPID
Tag Type
Name
Value
C-VLAN Tag
802.1q Tag Protocol Type
0x8100
OptiX OSN 550 Multi-Service CPE Optical Transmission
System
Configuration Guide
4 Configuring Ethernet Services
Issue 02 (2011-06-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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