Dynamic 802.1Q VLAN Overview
You can identify VLANs statically or dynamically. You can also configure a mix of static and dynamic VLANs on the same underlying interface.
For Ethernet, Fast Ethernet, Tri-Rate Ethernet copper, Gigabit Ethernet, 10-Gigabit Ethernet, and aggregated Ethernet interfaces supporting VPLS, Junos OS supports a subset of the IEEE 802.1Q standard for channelizing an Ethernet interface into multiple logical interfaces. Many hosts can be connected to the same Gigabit Ethernet switch, but they cannot be in the same routing or bridging domain.
To identify VLANs statically, you can reference a static VLAN interface in a dynamic profile. To identify subscribers dynamically, you use a variable to specify an 802.1Q VLAN that is dynamically created when a subscriber accesses the network.
Dynamic VLAN Configuration
You can configure the router to dynamically create VLANs when a client accesses an interface and requests a VLAN ID that does not yet exist. When a client accesses a particular interface, the router instantiates a VLAN dynamic profile that you have associated with the interface. Using the settings in the dynamic profile, the router extracts information about the client from the incoming packet (for example, the interface and unit values), saves this information in the routing table, and creates a VLAN or stacked VLAN ID for the client from a range of VLAN IDs that you configure for the interface.
Dynamic VLAN configuration supports the creation of IPv4 (inet), DHCPv4, IPv6 (inet6), and DHCPv6 VLANs.
Dynamic Mixed VLAN Ranges
Dynamic VLAN and dynamic stacked VLAN configuration supports mixed (or flexible) VLAN ranges. When you configure dynamic mixed VLAN ranges, you must create separate dynamic profiles for VLANs and stacked VLANs. Table 1 lists all valid combinations for the maximum number of dynamic profiles and VLAN and stacked VLAN ranges on a single underlying interface.
VLANs |
Stacked VLANs |
||
|---|---|---|---|
Maximum Number of Dynamic Profiles |
Maximum Number of VLAN Ranges Per Profile |
Maximum Number of Dynamic Profiles |
Maximum Number of Stacked VLAN Ranges Per Profile |
1 |
128 |
1 |
128 |
16 |
32 |
16 |
32 |
1 |
128 |
16 |
32 |
16 |
32 |
1 |
128 |
Table 1 shows the valid maximums for the following dynamic mixed VLAN range configuration scenarios, in this order:
Configurations that require up to 128 VLAN ranges and up to 128 stacked VLAN ranges on a single underlying interface. You must create one VLAN dynamic profile and one stacked VLAN dynamic profile, each with a maximum of 128 ranges per profile.
Configurations that require up to 32 VLAN ranges and up to 32 stacked VLAN ranges on a single underlying interface. You can configure up to 16 VLAN dynamic profiles and up to 16 stacked VLAN dynamic profiles, each with a maximum of 32 ranges per profile.
Configurations that consist of one VLAN dynamic profile with a maximum of 128 ranges, and up to 16 stacked VLAN dynamic profiles with 32 ranges each.
Configurations that consist of up to 16 VLAN dynamic profiles with 32 ranges each, and one stacked VLAN dynamic profile with a maximum of 128 ranges.
The following guidelines apply to the limits in Table 1 when you configure VLAN ranges and S-VLAN ranges for use with dynamic profiles:
These limits apply to both single-tagged and double-tagged dynamic VLAN ranges.
These limits apply only to MX Series routers with MPCs. For MX Series routers with Enhanced Queuing IP Services DPCs (DPCE-R-Q model numbers) or Enhanced Queuing Ethernet Services DPCs (DPCE-X-Q model numbers), the maximum number of VLAN ranges for a dynamic profile on an underlying interface remains unchanged at 32 VLAN ranges and 32 S-VLAN ranges.
These limits have no effect on the maximum number of VLAN IDs on a given underlying interface. The valid range of ID values for a dynamic VLAN range or dynamic S-VLAN range remains unchanged at 1 through 4094.