Outer MPLS Header

Starting with release 21.1.2.0, Extreme 9920 software supports outer Multiprotocol Label Switching Segment Routing (MPLS-SR). MPLS-SR packets without an outer VLAN tag (or 802.1BR/VN tag), are terminated if there is a matching configuration present in the ingress-group. The packets are filtered based on MPLS Label ID, Traffic Class, and Time-To-Live values of Bottom Of Stack (BOS) label.

MPLS labels from the outer tunnel are removed, and remaining packets are subjected to inner-tunnel processing or ingress policies. VLANs tagged outer Ethernet packets are not terminated, but are matched at ingress policy stage.

Note

MPLS-SR tunnel termination is supported in the following scenarios:

• MPLS-SR is the only tunnel present in the packets.
• MPLS-SR is the outermost tunnel and there is an inner-tunnel (for example, GTPU).

Limitations

The outer MPLS header limitations are as follows:

• The incoming traffic matching is based on the Bottom Of Stack MPLS label values. Other MPLS labels in the stack are not supported.
• The matched MPLS stream is terminated, and all MPLS labels from the label stack are removed.
• A maximum of four MPLS labels are supported.
• The inner frame must have an Ethernet header instead of direct IP header.
• The outer VxLAN tunnel limitations apply to MPLS as well. For more information, see Outer VXLAN Header.

Note

GRE tunnel encapsulation does not support MPLS packets. When MPLS packets are subjected to GRE encapsulation, the protocol ID in the GRE header is set to 0.