H3C S3600 Series User Manual

Operation Manual – VLAN
H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1
VLAN Overview
1-5
Only the IPX protocol supports 802.3 raw encapsulation format currently. This format is
identified by the two bytes whose value is 0xFFFF after the length field.
z 802.2 logical link control (LLC) encapsulation: the length field, the destination
service access point (DSAP) field, the source service access point (SSAP) field
and the control field are encapsulated after the source and destination address
field.
DSAP(1) SSAP(1) Control(1)DA&SA(12) Length(2) DATA
DSAP(1) SSAP(1) Control(1)DA&SA(12) Length(2)
DATA
DSAP(1) SSAP(1) Control(1)DA&SA(12) Length(2) DATA
DSAP(1) SSAP(1) Control(1)DA&SA(12) Length(2)
DATA
t Figure 1-7 802.2 LLC encapsulation forma
The DSAP field and the SSAP field in the LLC part are used to identify the upper layer
protocol. For example, the two fields are both 0xE0, meaning that the upper layer
protocol is IPX protocol.
z 802.2 sub-network access protocol (SNAP) encapsulation: the length field, the
DSAP filed, the SSAP field, the control field, the OUI field and the PID field are
encapsulated according to 802.2/802.3 packets.
OUI(3) PID(2)DSAP(1) SSAP(1) Control(1)DA&SA(12) Length(2) DATA
OUI(3) PID(2)DSAP(1) SSAP(1) Control(1)
DA&SA(12)
Length(2) DATA
OUI(3) PID(2)DSAP(1) SSAP(1) Control(1)DA&SA(12) Length(2) DATA
OUI(3) PID(2)DSAP(1) SSAP(1) Control(1)
DA&SA(12)
Length(2) DATA
OUI(3) PID(2)DSAP(1) SSAP(1) Control(1)DA&SA(12) Length(2) DATA
OUI(3) PID(2)DSAP(1) SSAP(1) Control(1)
DA&SA(12)
Length(2) DATA
t Figure 1-8 802.2 SNAP encapsulation forma
In 802.2 SNAP encapsulation format, the values of the DSAP field and the SSAP field
are always AA, and the value of the control field is always 3.
The switch differentiates between 802.2 LLC encapsulation and 802.2 SNAP
encapsulation according to the values of the DSAP field and the SSAP field.
 Note:
When the OUI is 00-00-00 in 802.2 SNAP encapsulation, the PID field has the same
meaning as the type field in Ethernet II encapsulation, which both refer to globally
unique protocol number. Such encapsulation is also known as SNAP RFC1042
encapsulation, which is standard SNAP encapsulation. The SNAP encapsulation
mentioned in this chapter refers to SNAP RFC 1042 encapsulation.

H3C S3600 Series Specifications

General

Brand	H3C
Model	S3600 Series
Category	Switch
Language	English