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802.1Q VLAN IDs and Ethernet Interface Types

 

A VLAN (virtual LAN) abstracts the idea of the local area network (LAN) by providing data link connectivity for a subnet. VLANs make it easy for network administrators to partition a single switched network to match the functional and security requirements of their systems without having to run new cables or make major changes in their current network infrastructure. Each VLAN can be uniquely identified by VLAN ID, which is transmitted & received as IEEE 802.1Q tag in an Ethernet frame.

You can partition the router into up to 4095 different VLANs—depending on the router model and the physical interface types—by associating logical interfaces with specific VLAN IDs.

VLAN ID 0 is reserved for tagging the priority of frames. VLAN IDs 1 through 511 are reserved for normal VLANs. VLAN IDs 512 and above are reserved for VLAN circuit cross-connect (CCCs).

For Gigabit Ethernet IQ interfaces and Gigabit Ethernet PICs with SFPs (except the 10-port Gigabit Ethernet PIC and the built-in Gigabit Ethernet port on the M7i router), you can configure flexible Ethernet services encapsulation on the physical interface. With flexible Ethernet services encapsulation, VLAN IDs from 1 through 511 are no longer reserved for normal VLANs.

The maximum number of user-configurable VLANs is 15 on each port of the Dense-FE PIC (8-port/12-port/48-port).

Table 1 lists VLAN ID range by interface type.

Table 1: VLAN ID Range by Interface Type

Interface Type

VLAN ID Range

Aggregated Ethernet for Fast Ethernet

1 through 1023

Aggregate Ethernet for Gigabit Ethernet

1 through 4094

4-port, 8-port, and 12-port Fast Ethernet

1 through 1023

48-port Fast Ethernet

1 through 4094

Tri-Rate Ethernet copper

1 through 4094

Gigabit Ethernet

1 through 4094

Gigabit Ethernet IQ

1 through 4094

10-Gigabit Ethernet

1 through 4094

100-Gigabit Ethernet

1 through 4094

Management and internal Ethernet interfaces

1 through 1023

Note

For Gigabit Ethernet IQ and Gigabit Ethernet PICs with SFPs (except the built-in Gigabit Ethernet port on the M7i router), VLAN IDs on a single interface can differ from each other.

Because IS-IS has an 8-bit limit for broadcast multiaccess media, you cannot set up more than 255 adjacencies over Gigabit Ethernet using VLAN tagging. For more information, see the Junos OS Routing Protocols Library.