H3C S3600 Series User Manual

Operation Manual – VLAN
H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1
VLAN Overview
1-4
I. Ethernet II and 802.2/802.3 encapsulation
In the link layer, there are two main packet encapsulation types: Ethernet II and
802.2/802.3, whose encapsulation formats are described in the following figures.
Ethernet II packet:
Type(2)DA&SA(12) DATAType(2)DA&SA(12) DATADA&SA(12) DATAType(2)DA&SA(12) DATADA&SA(12) DATAType(2)DA&SA(12) DATADA&SA(12) DATA
Figure 1-4 Ethernet II encapsulation format
802.2/802.3 packet:
OUI(3) PID(2)DSAP(1) SSAP(1) Control(1)DA&SA(12) Length(2) DATAOUI(3) PID(2)DSAP(1) SSAP(1) Control(1)DA &SA (12) Length(2) DATAOUI(3) PID(2)DSAP(1) SSAP(1) Control(1)DA&SA(12) Length(2) DATAOUI(3) PID(2)DSAP(1) SSAP(1) Control(1)DA &SA (12) Length(2) DATA
t Figure 1-5 802.2/802.3 encapsulation forma
In the two figures, DA and SA refer to the destination MAC address and source MAC
address of the packet respectively. The number in the bracket indicates the field length
in bits.
The maximum length of an Ethernet packet is 1500 bytes, that is, 5DC in hexadecimal,
so the length field in 802.2/802.3 encapsulation is in the range of 0x0000 to 0x05DC.
Whereas, the type field in Ethernet II encapsulation is in the range of 0x0600 to
0xFFFF.
 Notes:
Presently, H3C S3600 series switches recognize packets with the value of the type field
being in the range 0x05DD to 0x05FF as 802.2/802.3 encapsulated packets.
The switch identifies whether a packet is an Ethernet II packet or an 802.2/802.3 packet
according to the ranges of the two fields.
II. Encapsulation formats of 802.2/802.3 packets
802.2/802.3 packets are encapsulated in the following three formats:
z 802.3 raw encapsulation: only the length field is encapsulated after the source and
destination address field, followed by the upper layer data. The type field is not
included.
Length(2)DA&SA(12) DATA
Length(2)
DA&SA(12) DATA
DA&SA(12) DATA
Length(2)DA&SA(12) DATADA&SA(12) DATA
Length(2)
DA&SA(12) DATA
DA&SA(12) DATA
Figure 1-6 802.3 raw encapsulation format

H3C S3600 Series Specifications

General

Brand	H3C
Model	S3600 Series
Category	Switch
Language	English