• There was a situation that requested to have certain ports to be configured into a specific vlan. (This occurs when there's a new set up with these machines in a different location but require a specfic vlan to get an ip address; trying to be vague in order to not pin point where I work at) I usually use switchport access vlan (vlan name) and call it a day.

    However, i noted that the vlan doesn't reside in that switch and when searching for all vlans, it wasn't listed there. Usually I would attempt to trunk the port by checking cdp neighbors but wasn't too comfortable with it. I asked my co worker to help, and our lead mentioned that it's a layer 2 switch and that vlan doesn't reside on that layer 2 network. After back and forth name calling and bashing from the other department who made that original request, they resolved the issue. (my assumption is that they plugged into the layer 3 switch instead).

    This is what I know for sure before this hooplah happened: I know that VLANS are layer 2. I know layer 3 has IP addressing.

    The switches were: 3560a, and 3750xa

    Are the layer 3 switches allows the VLANS to pass traffic across a trunk through routing but the layer 2 switch can't do that feature?

    I'm trying to understand this better so when I have to explain it, not only does it make sense to me but I can interpret my answer multiple different ways because not everyone can understand one way of answering a question.


  • @TaylorBrown said in Layer 2 & Layer 3 switches:

    Are the layer 3 switches allows the VLANS to pass traffic across a trunk through routing but the layer 2 switch can't do that feature?

    Hi,

    Just look at this for example (basics):
    https://en.wikipedia.org/wiki/Virtual_LAN

    for example, Cisco SG300 or SG350(L3) series, on SG300 can be selected to run L2 or L3 mode

    handles VLANs in L2, but you cannot to address the VLAN interface with IP

    L2 VLAN on MAC basis or L3 VLAN (hmmm) with IP + of course MAC

    +++edit:
    even easier:
    https://community.fs.com/blog/layer-2-switch-vs-layer-3-switch-which-one-do-you-need.html


  • There was a situation that requested to have certain ports to be configured into a specific vlan. (This occurs when there's a new set up with these machines in a different location but require a specfic vlan to get an ip address; trying to be vague in order to not pin point where I work at) I usually use switchport access vlan (vlan name) and call it a day.

    However, i noted that the vlan doesn't reside in that switch and when searching for all vlans, it wasn't listed there. Usually I would attempt to trunk the port by checking cdp neighbors but wasn't too comfortable with it. I asked my co worker to help, and our lead mentioned that it's a layer 2 switch and that vlan doesn't reside on that layer 2 network. After back and forth name calling and bashing from the other department who made that original request, they resolved the issue. (my assumption is that they plugged into the layer 3 switch instead).

    This is what I know for sure before this hooplah happened: I know that VLANS are layer 2. I know layer 3 has IP addressing.

    The switches were: 3560a, and 3750xa

    Are the layer 3 switches allows the VLANS to pass traffic across a trunk through routing but the layer 2 switch can't do that feature?

    I'm trying to understand this better so when I have to explain it, not only does it make sense to me but I can interpret my answer multiple different ways because not everyone can understand one way of answering a question. https://9apps.ooo/

    issue got solved!!


  • our lead mentioned that it's a layer 2 switch and that vlan doesn't reside on that layer 2 network

    This means the switch is implemented at layer 2 only... i.e. either routing is disabled or the functionality doesn't exist on that particular switch. Without knowing more about the design, we can only offer generalities, but most likely your layer 2 switch has an uplink that is trunked to either a distribution stack or a router. There are various solutions, but what your lead most likely meant was since the VLAN doesn't exist on the switch, it will need to be built out from the distribution out to the access layer.

    In other words, the VLAN needed to be added to the layer 2 switch and then allowed over the trunk (on both sides).