Worth Reading: Single-Port LAGs
Lindsay Hill described an excellent idea: all ports on your switches routers should be in link aggregation groups even when you have a single port in a group. That approach allows you to:
- Upgrade the link speed without changing any layer-3 configuration
- Do link maintenance without causing a routing protocol flap
It also proves RFC 1925 rule 6a, but then I guess we’re already used to that ;)
I had this idea when I first learned how do LAG work Way over a decade ago.
We also get the benefit of lacp that it makes sure the forwarding is bidirectional.
Bidirectional forwarding detection is solved (for the physical layer) in GE/10GE world. More details @ https://blog.ipspace.net/2020/11/detecting-network-failure.html