VRRP is still useful, and for those who find it useful it has been extended to IPv6 [RFC5798]. Vendors, such as Cisco, have already begun shipping functional implementations as well it would seem. There are certainly pieces of IPv6 that will need refinement (and we will likely see that happen over time, after it is dominant). Mobility and IPsec, for example, were touted as big benefits of IPv6, but they didn't end up being that important (or useful) in their current state. The ability to have multiple prefixes from different routers, and a failover mechanism was really a pre-NAT and pre-VRRP idea. It's not the common deployment that it was envisioned to be, and our expectations of how fast these things happen has become a lot higher. Still, minor extensions could be made to these standard to achieve a lot of the desired behavior, so I haven't given up on it all completely. It's hard to predict the future, and it's been over a decade since the design for IPv6 was solidified and began to be implemented. Let's not forget that what we call "Ethernet" today is very different from Bob Metcalfe's Ethernet. On Fri, Dec 30, 2011 at 11:47 AM, Kevin Loch <kloch@kl.net> wrote:
Steven Bellovin wrote:
VRRP? The Router Discovery Protocol (RFC 1256). But given how much more reliable routers are today than in 1984, I'm not convinced it's that necessary these days.
VRRP is an absolutely essential protocol in today's Internet. We use it on every non-bgp customer port. Routers still have routing and performance issues, hardware failures and routine software upgrades. The layer2 infrastructure between the routers and the customer is also susceptible to various hardware/software/maintenance problems and fiber cuts and VRRP can help work around some of those. A nice side benefit is the virtual mac addresses that allow for migration to new routers without the mac address of the default gateway changing.
One key advantage of VRRP over RA's is that you can have multiple instances on the same layer2 network (vlan) with different functions.
It is very common to have different "routers" (routers, firewalls or load balancers) on the same vlan with different functions in hosting environments. It is also sometimes necessary to have multiple default gateways on the same vlan for load balancing or traffic engineering. RA/auto configuration is incompatible with all but the most trivial configurations.
- Kevin
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