does loopback address of a router have a vlan??

[archanabansla]

hi all,

i need to know if the interface IP for BGP link and the loopback address of router have a vlan for them or not??

is yes, then how to check that?

[Peter Paluch]

Hi,

A loopback interface does not belong to any VLAN. VLANs are related to Ethernet interfaces only.

If a VLAN is being used for an Ethernet interface on a router: this is simple. If the interface in question is the physical interface (e.g. Gi0/0 or Fa0/0) then there is no specific VLAN being configured. If the interface in question is a subinterface, such as Fa0/0.1, and contains the encapsulation dot1q command then a VLAN is in use and its number can be determined from the encapsulation dot1q command.

Why are you actually asking this question?

Best regards,
Peter

[Richard Burts]

Peter

While I basically agree with your response I would propose one refinement. If we are looking at the physical Ethernet interface of a router and if that interface is connected to a switch access port then there is certainly a VLAN associated with the switch side. And one might then also say that the VLAN is associated with the router physical interface.

Perhaps another way to look at it starts from the fact that a defining characteristic of a VLAN is that it defines a layer 2 broadcast domain. A router physical interface also defines a layer 2 broadcast domain.

HTH

Rick