H3C Technologies H3C WX3000 Series Unified Switches - Manual (Page 80)

10-7
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.
Procedure for the Switch to Judge Packet Protocol
Figure 10-9 Procedure for the switch to judge packet protocol
Receive
packets
Type(Length)
field
Ethernet II
encapsulation
Match the
type value
Invalid packets
that cannot be
matched
802.2/802.3
encapsulation
Control
field
Invalid packets
that cannot be
matched
dsap/ssap
value
802.2 SNAP
encapsulation
Match the
dsap/ssap value
802.2 LLC
encapsulation
Match the
type value
802.3 raw
encapsulation
0x05DD to 0x05FF 0x0600 to 0xFFFF
0 to 0x05DC
Value is not 3
Value is 3
Both are AA Both are FF
Other values
Receive
packets
Type(Length)
field
Ethernet II
encapsulation
Match the
type value
Invalid packets
that cannot be
matched
802.2/802.3
encapsulation
Control
field
Invalid packets
that cannot be
matched
dsap/ssap
value
802.2 SNAP
encapsulation
Match the
dsap/ssap value
802.2 LLC
encapsulation
Match the
type value
802.3 raw
encapsulation
0x05DD to 0x05FF 0x0600 to 0xFFFF
0 to 0x05DC
Value is not 3
Value is 3
Both are AA Both are FF
Other values
Encapsulation Formats
Table 10-1 lists the encapsulation formats supported by some protocols. In brackets are type values of
these protocols.