US patent 5473599

Henning Brauer hb-nanog at
Thu May 8 07:48:26 UTC 2014

* Owen DeLong <owen at> [2014-05-08 07:16]:
> If they take their ball and go home, that's fine. The problem is that they seem to occasionally have their ball brought (by systems administrators) to networks where the network engineers are already running VRRP on routers (for example) and because:
> 	1.	The systems administrators don't necessarily have in-depth knowledge of what the network is doing.

nothing technology can solve

> 	2.	The network administrators don't necessarily get told about every detail of the Systems administrators intentions.

nothing technology can solve

> 	3.	There's no knowledge among the two groups that either is using the other protocol (CARP vs. VRRP)

nothing technology can solve

> 	4.	There's even less knowledge that the two are going to fight with each other.

that is a lie, they coexist just fine.
even with "conflicting" mac addrs you just get log spam.

> OTOH, if the BSD folk had (or in the future did) fix CARP so that instead of trying to steal VRRP MAC addresses in a conflicting manner, it would either use a non-conflicting MAC prefix (how about one with the locally assigned bit set, such as the VRRP Mac | 0x02000:0000:0000) and make a legitimate attempt at getting CARP into an RFC with a legitimately assigned protocol number, everyone could get along without issue.

awaiting your diff.

Henning Brauer, hb at, henning at
BS Web Services GmbH, AG Hamburg HRB 128289,
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