Re: Last-resort tunnel recommendations on WAN network ...

https://en.wikipedia.org/wiki/Common_Address_Redundancy_Protocol
 ---
Cisco informed the OpenBSD <https://en.wikipedia.org/wiki/OpenBSD>
developers that it would enforce its patent on HSRP. Cisco's position may
have been due to their lawsuit with Alcatel. As Cisco's licensing terms
prevented an open-source VRRP implementation, the OpenBSD developers began
developing CARP instead. OpenBSD focuses on security. They designed CARP to
use cryptography <https://en.wikipedia.org/wiki/Cryptography>. This made
CARP fundamentally different from VRRP and ensured that CARP did not
infringe on Cisco's patent. CARP became available in October 2003.[3]
<https://en.wikipedia.org/wiki/Common_Address_Redundancy_Protocol#cite_note-3>
Later, it was integrated into FreeBSD
<https://en.wikipedia.org/wiki/FreeBSD> (first released in May 2005 with
FreeBSD 5.4),[4]
<https://en.wikipedia.org/wiki/Common_Address_Redundancy_Protocol#cite_note-4>
NetBSD <https://en.wikipedia.org/wiki/NetBSD> and Linux
<https://en.wikipedia.org/wiki/Linux> (ucarp).[1]
<https://en.wikipedia.org/wiki/Common_Address_Redundancy_Protocol#cite_note-ucarp_manpage-1>
While Cisco's US patent expired in 2014, the two incompatible protocols
continue to coexist.

daniel

On Thu, Mar 19, 2026 at 8:12 PM Owen DeLong via NANOG <[email protected]>
wrote:

> Disagree strongly here.
>
> CARP is an abomination that should never have been inflicted on the world.
> CARP is an act of arrogance wherein the BSD developers went to the IETF and
> demanded a port allocation for a service that was largely duplicative of
> existing functionality provided by VRRP. They refused to go through the
> internet-draft process or work with the relevant working group(s) and
> instead ended up just overloading the port assignments for VRRP such that
> CARP becomes a huge PITA for any network engineer who encounters it on a
> network running or deploying VRRP.
>
> The BSD team lost a lot of my previous respect when they did this. Yes,
> BSD routing is also a viable candidate, but CARP just shouldn’t be.
>
> Owen
>
>
> > On Mar 19, 2026, at 11:07, Owen DeLong <[email protected]> wrote:
> >
> > 
> >
> >> Yes, systemd-networkd is very capable (if arcane and unfriendly at
> times) for static configuration persistence.  NetworkManager is more geared
> toward and indeed seems better for systems that are using lots of runtime
> dynamic configuration (DHCP, 802.1x, etc.) and also provides better desktop
> environment integration.
> >
> > Agree to disagree here. The ability to control DHCP and 802.1x in
> systemd-networkd is far more mature and capable than NetworkManager. The
> one and only place where network manager shines is if you are traversing
> many different wireless networks with different but basic configurations
> and limited IPv6 concerns. (It’s great for a normal laptop user who can
> manage it entirely within the GUI).
> >
> > I would never use it on anything doing any sort of routing or bridging.
> Not even like a mobile hotspot.
> >
> >> I mostly use systemd-networkd on my generic-Linux-distro-as-a-router
> and adjacent (local DHCP/DNS, for example) systems.
> >
> > I’ve decided that it’s the best Swiss Army knife for my needs and rather
> than try to stay up on the idiosyncrasies of multiple packages, I try to
> just use it wherever I can.
> >
> > YMMV.
> >
> > Owen
> >
>
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>
> https://lists.nanog.org/archives/list/[email protected]/message/FHSFXQ44CSHWID2C47UKWXLOEOL3CZIJ/
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