Subinterface VLAN configuration

Untagged bridged and routed subinterfaces are supported on all platforms that support bridged subinterfaces, including 7220 IXR-Dx, 7215 IXS-A1, 7250 IXR, and 7730 SXR platforms.

When a subinterface is untagged bridged and routed, the Ethernet interface is configured as vlan-tagging false.

Only one untagged subinterface is supported on an Ethernet interface.

All incoming frames on the interface are classified into the untagged subinterface whether the frames are tagged or untagged.

--{ * candidate shared default }--[ interface ethernet-1/1 ]--
A:srl1# info
    admin-state enable
    vlan-tagging false
    subinterface 1 {
        type bridged
    }

Dot1q tagged bridged subinterfaces are supported on 7220 IXR-Dx, 7215 IXS-A1, 7250 IXR, and 7730 SXR platforms.

When a bridged subinterface is Dot1q tagged, the Ethernet interface is configured as vlan-tagging true and multiple subinterfaces are supported on the same interface.

Ingress traffic is classified into a subinterface based on the associated Dot1q tagging.

Bridged subinterfaces support Dot1q VLAN ranges. When a bridged subinterface is configured for a Dot1q VLAN range, traffic matching any VLAN in the range is associated with the bridged subinterface.

For example, you can configure a bridged subinterface with the Dot1q VLAN range 10 to 100. When an attached device sends traffic that has a VLAN ID in the range 10 through 100, the traffic is associated with the bridged subinterface.

A bridged subinterface can support a single VLAN range or multiple VLAN ranges. The following figure shows a configuration with a single VLAN range.

In this figure, the Bare Metal (BM) server is attached to a MAC VRF, and LAG-bridged subinterfaces are associated with the Dot1q VLAN range 1-4000. Traffic issued by the BM server with a VLAN ID matching any value in the configured range is associated with the bridged subinterface. VLAN IDs 4001-4095 are not associated with the subinterface.

The following figure shows a configuration with multiple VLAN ranges associated with a bridged subinterface.

In this figure, VLAN ranges are selectively associated with a mac-vrf. VLAN IDs 1–100 are associated with MAC-VRF 20001 (which uses VNI 20001), and VLAN IDs 101–200 are associated with MAC-VRF 20002 (which uses VNI 20002).

In both figures, it is expected that all the leaf nodes attached to the same BD use the same VLAN ranges on all their bridged subinterfaces for the mac-vrf. The Dot1q VLAN tags of the incoming frames are not stripped off at the ingress subinterface. At the egress subinterface (which is configured with the same VLAN range as the ingress subinterface), no additional Dot1q tag is pushed onto the frames.

An SR Linux system can support up to 8,000 subinterfaces that have VLAN ranges, with up to 8 VLAN ranges per interface.

VLAN ranges can be configured on bridged subinterfaces of a mac-vrf with or without IRB subinterfaces. When an IRB subinterface is present in the same mac-vrf where the VLAN range subinterface is configured, incoming frames containing tags with a MAC DA equal to the IRB and associated with a Dot1q VLAN range subinterface are dropped. On egress, traffic coming from the IRB is not tagged if the destination is associated with a VLAN range subinterface.

VLAN ranges cannot overlap within the same subinterface or across subinterfaces of the same physical interface. In addition, ranges configured in subinterface a and individual VLAN ID values configured in a single-tagged subinterface b cannot overlap if a and b are defined in the same interface.

SR Linux supports QinQ bridged subinterfaces on 7250 IXR and 7730 SXR platforms. You can configure double-tagged subinterfaces when an Ethernet interface is configured as vlan-tagging true.

The double-tagged command enables QinQ subinterfaces in a given Ethernet interface and is only configured in bridged subinterfaces.

Both inner-vlan-id and outer-vlan-id must be configured.

The following table describes the possible subinterfaces that QinQ traffic is classified into.

Untagged, single-tagged, and double-tagged subinterfaces are supported on the same Ethernet or LAG interface.

The following example shows untagged, single-tagged, and double-tagged subinterfaces under the same interface.

--{ * candidate shared default }--[  ]--
A:srl1# info interface ethernet-1/1
    interface ethernet-1/1 {
        description qinq-interface
        admin-state enable
        vlan-tagging true        
        subinterface 1 {
            type bridged
            vlan {
                encap {
                    single-tagged {
                        vlan-id 1
                    }
                }
            }
        }        
        subinterface 2 {
            type bridged
            vlan {
                encap {
                    double-tagged {
                        inner-vlan-id 100
                        outer-vlan-id 100
                    }
                }
            }
        }
        subinterface 3 {
            type bridged
            vlan {
                encap {
                    untagged {
                    }
                }
            }
        }
    }

The following table shows the different VLAN encapsulation options supported across platforms.