How many untagged VLANs can be configured on an EX Series switch port?

A.
0

B.
1

C.
4095

D.
4096

Explanation:
To identify which VLAN a packet belongs to, all packets on an Ethernet VLAN are identified by a numeric tag, as defined in the IEEE 802.1Q standard. For a simple network that has only a single VLAN, all traffic has the same default 802.1Q tag, which is the only VLAN membership that does not mark the packet as tagged. These packets are untagged native packets.

When an Ethernet LAN is divided into VLANs, each VLAN is identified by a unique 802.1Q ID. That unique VLAN 802.1Q ID is applied to all packets so that network nodes receiving the packets can detect which non-default VLAN the packets belong to. The presence of these unique IDs means the packets are now tagged. VLAN tags 0 and 4095 are reserved by the Juniper Networks Junos operating system (Junos OS), so you cannot assign those tags to a VLAN in your network. The VLAN tags 1 through 4094 can be assigned to VLANs.