MPLS/BGP/VPNs has long been a “carrier technology” used for isolating customers traffic. In general, MPLS is really great at interconnecting data centers and branches, and branches to each other. Also, MPLS supports network virtualization with its IP VPNs and E-VPNs capabilities. This is much needed features in data centers. Moreover, traffic engineering is often important between data centers, and MPLS helps there too. Yet, so far, MPLS hasn’t penetrated the DC to any great extent. The question then is, Why? and what prevented MPLS from being used in the data center?
From 10,000 feet high, MPLS has the following issues in data center:
- Managing MPLS is Complex: MPLS is also thought to be hard to configure, manage, debug and troubleshoot because of the flexibility of the underlying protocols and the number of knobs and whistles. Isolating issues can be difficult. Mediating between dueling vendors adds a non-technical dimension to the problem.
- Need higher/more skilled staff: Different and arguably higher skill set needed for MPLS implementation.
- MPLS is expensive (both capex and opex): MPLS hardware more expensive than plain Ethernet switches. In part, because of the flexibility that MPLS demands; in part, because of the robust control plane that is expected with MPLS hardware.
- Lack of IPv6/MPLS support on data center switches: MPLS does not support IPv6. Neither LDP nor MPLS Traffic Engineering (MPLS TE) interact with IPv6. To benefit from the MPLS features (for example, BGP-free network core, fast recovery with Fast Reroute or Traffic Engineering), you have to transport IPv6 across an MPLS-enabled IPv4 core. To connect IPv6 servers/apps, you should use the 6PE technology (cannot get on any data center switches); if you want to offer IPv6 VPN services, use 6VPE technology (again cannot get on any data center switches)
So how to build next generation data centers?
MPLS has it’s place in certain types of networks but it no longer has a place the data centers. SDN and VxLAN Overlay networking easily replace MPLS and provide far more functions, service and visibility.