Networking community,

I’ve been pondering the design evolution of Ethernet and its frames, particularly in the context of historical updates and the absence of a Time-to-Live (TTL) feature. We know Ethernet frames have been updated over time for various functionalities. For instance:

• VLAN tagging was introduced with 802.1Q.
• Priority tagging came with 802.1p for QoS capabilities.
• The concept of Jumbo Frames to handle larger data sets.

Considering these updates, I’m curious why a TTL value was never introduced to Ethernet frames, especially given the known issues with broadcast loops. Spanning Tree Protocol (STP) addressed this to an extent, but could the introduction of a TTL in Ethernet frames have been a more direct or efficient solution?

Wouldn’t a frame-level TTL, implemented in a backward-compatible way like other Ethernet frame updates, have offered a more foundational solution to the problem of broadcast loops?