BGP triggered IP-in-GUE Encapsulation provides a mechanism for dynamically creating tunnels in a core network using an IP underlay.  IP-in-GUE (Generic UDP Encapsulation) encapsulates IP traffic in an IPv4/UDP header.  IP unicast routes to destinations reachable across the core network are learned via BGP at the ingress edge.

This feature when configured enables users to rewrite the DSCP of the GUE encapsulated header on IP-over-UDP tunnels while preserving the TOS value of the inner IP ( IPv4 / IPv6 ) payload. Starting from software version 4.34.1F, the CLI configuration to enable or disable DSCP preserve globally on the egress interface introduces a clear distinction in the behavior of GUE encapsulation on the core facing interface of the IP-over-UDP tunnels.

Generic UDP Encapsulation (GUE) is a general method for encapsulating packets of arbitrary IP protocols within a UDP tunnel. While GUE supports an extensible header format with optional data, currently we only support the variant 1 header format, which directly encapsulates the IPv4/IPv6 payload without a GUE header. 

Gue EOS 4.30.1F IP-Over-UDP