This confuses me as default untagged VLAN on my CRS309 is VLAN1.Specify the VLAN ID that the switch must set on untagged (VLAN0) traffic for each access port:
So basicly, vlan 0shouldbe a frame without 802.1Q header.
In that case why is VLAN1 the default on my RB4011 and CRS309?There is no such vlan id in 802.1Q Ethernet standart. So it's just Switch OS interpretation of untagged vlan traffic.
https://en.wikipedia.org/wiki/IEEE_802.1Q
P.S.: "A 12-bit field specifying the VLAN to which the frame belongs. The hexadecimal values of 0x000 and 0xFFF are reserved. All other values may be used as VLAN identifiers, allowing up to 4,094 VLANs. The reserved value 0x000 indicates that the frame does not carry a VLAN ID".
So basicly, vlan 0shouldbe a frame without 802.1Q header.
Well yeah, I meant it will be untagged with 802.1Q header. Correction.So basicly, vlan 0shouldbe a frame without 802.1Q header.
Not exactly. Frame with 802.1Q header which is there explicitly because of using other fields - QoS/priority, but without intent of using VLANs, will have field VID set to 0. Which essentially makes it VLAN-untagged frame. Or in ROS language:untaged-or-priority-taged
Because vlan 1 is a default vlan in any switch in a world. There are some layer 2 protocols tha are using vlan 1 to work, even if you'll use some tagged traffic with different vlans. You can use vlan 1 as tagged, untagged or native vlan traffic.In that case why is VLAN1 the default on my RB4011 and CRS309?There is no such vlan id in 802.1Q Ethernet standart. So it's just Switch OS interpretation of untagged vlan traffic.
https://en.wikipedia.org/wiki/IEEE_802.1Q
P.S.: "A 12-bit field specifying the VLAN to which the frame belongs. The hexadecimal values of 0x000 and 0xFFF are reserved. All other values may be used as VLAN identifiers, allowing up to 4,094 VLANs. The reserved value 0x000 indicates that the frame does not carry a VLAN ID".
So basicly, vlan 0shouldbe a frame without 802.1Q header.
There is no zero id in standart.
It is just will be without vlan id at all with all other fields.There is no zero id in standart.
Not an actual VLAN 0, no. But a dot1q frame header with 0 as the VLAN ID is perfectly valid; it just means a priority-tagged frame without a VLAN ID.
