About VLANs.
Note gathered during some reading about VLANs. See also the vconfig man page.
- VLAN architecture and frame tagging techniques. 802.1q specifies a tag header following the source MAC address field.
- VLAN tagged frames carry VLAN id and priority information (priority use is defined in 802.1p)
- VLANs can be setup as port based, MAC based or Layer3 protocol and address based.
- CRC (Cyclic Redundancy Check). Remainder of the bit string converted to modulo 2 coefs polynomial, divided by an other pre-defined polynomial (key.) Ethernet uses key 0x04c11db7 (degree-32, 32nd degree coef implicitely 1.)
- The CRC is added to the message polymomial after multiplication by x^32 and sent,upon recomputation, the result should be zero. More info here.
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