Building network automation solutions

One of my readers successfully deployed LDPv6 in their production network:

We are using LDPv6 since we started using MPLS with IPv6 because I was used to OSPF/OSPFv3 in dual-stack deployments, and it simply worked.

Not everyone seems to be sharing his enthusiasm:

Now some consultants tell me that they know no-one else that is using LDPv6. According to them “everyone” is using 6PE and the future of LDPv6 is not certain.

I would believe that the future of LDPv6 is uncertain because the vendors are furiously pushing segment routing, be it as a control-plane addition to MPLS data plane or as a completely new IPv6-based data plane.

However, let’s start with the basics. If plan to use IPv4+IPv6 throughout your network, and already use LDP, then LDPv6 is the natural way to go. However:

• While you can run LDPv6 on Junos, IOS XR, and Nokia/ALU¹, there’s still no LDPv6 on Arista EOS or Cisco IOS XE (more details)
• LDP/IGP interactions are tricky, and introducing LDPv6 will more than double your headaches – now you’ll have to deal with OSPF/LDP and OSPFv3/LDPv6 interactions.

6PE is an obvious alternative, and since L3VPN and EVPN often cannot use IPv6 next hops, it might still make sense to stay with an IPv4-only core transport network if you plan to offer more than simple IPv4/IPv6 transport. 6PE is also supported on a wider variety of platforms than LDPv6.

In greenfield networks, SR-MPLSv6² would be a viable alternative to LDPv6, assuming it’s supported by the platforms you’re interested in³. It would also simplify your protocol stack, particularly if you use IS-IS as the routing protocol.

Finally, if you need an excuse to burn way too much money replacing still-working gear with the latest gizmos while ensuring job security for the next decade or so, you could decide to go for an IPv6-only network implementing all services with SRv6. I wish you plenty of luck, and would love to hear how well it worked out for you.