CTS MCT-RACK-12-MGM, Руководство пользователя

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SFD Start Frame Delimiter 2 bits Marks the beginning of the header
DA Destination Address 6 bytes The MAC address of the destination
SA Source Address 6 bytes The MAC address of the source
TCI Tag Control Info 2 bytes set to 8100 for 802.1p and Q tags
P Priority 3 bits Indicates 802.1p priority level 0-7
C Canonical Indicator 1 bit Indicates if the MAC addresses are in
Canonical format
– Ethernet set to “0”
VID VLAN Identifier 12 bits Indicates the VLAN (0-4095)
T/L Type/Length Field 2 bytes
Ethernet II “type” or 802.3 “length”
Payload < or = 1500 bytes User data
FCS Frame Check Sequence
4 bytes Cyclical Redundancy Check
IEEE 802.1q Tag VLAN Mode:
Enable or disable IEEE 802.1q Tag VLAN mode, or select
Bypass Ctag Mode which ignore C-tag checking.
Important VLAN Concepts for 802.1Q VLAN Configuration:
There are two key concepts to understand.
-
Access-VLAN specifies the VLAN ID to the port that will assign the VLAN ID to
untagged traffic from that port. A port can only be assigned to one Access-VLAN at a
time. When the port is configured as Access Mode , the port is called an Access Port ,
the link to/from this port is called an Access Link . The VLAN ID assigned is called PVID .
- Trunk-VLAN specifies the set of VLAN IDs that a given port is allowed to receive and
send tagged packets. A port can be assigned to multiple Trunk-VLANs at a time. When
the port is configured as Trunk Mode , the port is called a Trunk Port , the link to/from
this port is called a Trunk Link . The VLAN ID assigned is called VID .
A port can be configured as below 802.1q VLAN modes :
- Access Mode :
Access Links (the link to/from access ports) are the most common type of links on any
VLAN. All
network hosts (such as PCs) connect to the Access Links in order to gain
access to the local network. We configure only one Access-VLAN per port, that is, the
VLAN ID the network hosts will be allowed to access.
It is important to note at this point that any network host connected to an Access Port