Procedure For The Switch To Judge Packet Protocol - H3C S7500 Series Operation Manual

Operation Manual – VLAN
H3C S7500 Series Ethernet Switches
DA&SA(12)
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 RFC 1042
encapsulation, which is standard SNAP encapsulation. The SNAP encapsulation
mentioned in this chapter refers to SNAP RFC 1042 encapsulation.

1.3.3 Procedure for the Switch to Judge Packet Protocol

Ethernet II Ethernet II Ethernet II Ethernet II
encapsulation encapsulation encapsulation encapsulation
Match the Match the Match the Match the
type value type value type value type value
Figure 1-9 Procedure for the switch to judge packet protocol
Length(2) DSAP(1)
Receive packets Receive packets Receive packets Receive packets
0x600 0x600 0x600 0x600 0x600 0x600 0x600 to 0xFFF 0x600 0x600 0x600 0x600 0x600 0x600 0x600 0x600 0x600 0x600 to 0xFFF 0x600 0x600 0x600 to 0xFFF 0x600 0x600 0x600 to 0xFFF 0x600 0x600 0x600 0x600 0x600 0x600 0x600 0x600 0x600
Type (length ) field Type (length ) field Type (length ) field Type (length ) field
Both are FF Both are FF Both are FF Both are FF Both are FF Both are FF Both are FF
Raw Raw Raw Raw Raw Raw Raw
encapsulation encapsulation encapsulation encapsulation encapsulation encapsulation encapsulation
SSAP(1) Control ( 1) OUI(3)
t
0x05DC to 0x0600 0x05DC to 0x0600 0x05DC to 0x0600 0x05DC to 0x0600
0 to 0x05DC 0 to 0x05DC 0 to 0x05DC 0 to 0x05DC
802.3 encapsulation 802.3 encapsulation 802.3 encapsulation 802.3 encapsulation 802.3 encapsulation 802.3 encapsulation 802.3 encapsulation
Value is not 3 Value is not 3 Value is not 3 Value is not 3
Control field Control field Control field Control Control Control Control field Control
Value is 3 Value is 3 Value is 3 Value is 3
Both are AA Both are AA Both are AA Both are AA Both are AA Both are AA Both are AA
Dsap Dsap Dsap Dsap Dsap Dsap Dsap Dsap Dsap Dsap Dsap
ssap ssap ssap ssap ssap ssap ssap ssap ssap ssap ssap
Other values Other values Other values Other values Other values Other values Other values Other values Other values Other values Other values
llc llc llc llc llc llc llc llc encapsulation llc llc llc llc llc llc llc encapsulation llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc encapsulation llc llc llc llc llc llc llc llc llc encapsulation llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc llc
Match dsap Match dsap Match dsap Match dsap Match dsap Match dsap Match dsap Match dsap Match dsap Match dsap Match dsap
and ssap value and ssap value and ssap value and ssap value and ssap value and ssap value and ssap value and ssap value and ssap value and ssap value and ssap value
1-8
Chapter 1 VLAN Overview
PID(2) Data
Inv Inv Inv Inv alid packets that alid packets that alid packets that alid packets that
c c c c annot be matched annot be matched annot be matched annot be matched
Invalid pack Invalid pack Invalid pack Invalid pack ets that ets that ets that ets that
cannot be cannot be cannot be cannot be matched matched matched matched
snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap encapsulation snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap encapsulation snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap snap encapsulation snap snap snap snap snap snap encapsulation snap snap snap snap snap snap snap snap snap
Match Match Match Match Match Match Match Match Match Match Match
type type type type type type type type type type type