3com WX3000 Manuel D’Utilisation
1-7
Procedure for the Switch to Judge Packet Protocol
Figure 1-9 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
lists the encapsulation formats supported by some protocols. In brackets are type values of
these protocols.
Table 1-1 Encapsulation formats
Encapsulation
Protocol
Ethernet II
802.3 raw
802.2 LLC
802.2 SNAP
IP (0x0800)
Supported
Not supported Not
supported Supported
IPX (0x8137)
Supported
Supported Supported Supported
AppleTalk
(0x809B)
(0x809B)
Supported
Not supported
Not supported
Supported
Implementation of Protocol-Based VLAN
The switching engines of the devices assign the packet to the specific VLAN by matching the packet
with the protocol template.