For those interested by Provider to Clients connectivity, see Provider Backbone Bridge standard (PBB). This is a part of 802.1ah standard.
PBB is something like the big father of QinQ and Vlans, (802.1ad - 802.1q).
It does allow to isolate clients Mac adresses from the provider backbone, and does allow to easily manage client circuits, using a mapping between clients QinQ or Vlan tags and provider service circuits.
802.1ah do allow network control and monitoring through Ethernet OAM protocol. This is not the case with 802.1ad. OAM do allow fast detect, repair and convergence to avoid gaps more than 50 ms, like in SDH world.
For Provider Networks, there is 802.1Qay, or PBB-TE, Provider Backbone Bridge Traffic Engineering, disabling RSTP and flooding - broadcasting compared to 802.1ah.
According to Wikipedia :
"PBB-TE equipment leverages economies of scale inherent in Ethernet, promising solutions that are 30% to 40% cheaper than T-MPLS networks with identical features and capabilities, giving PBB-TE a better overall return on investment."
PBB is considered like a better alternative to MPLS. It is less costly and less complex, and it integrates more easily in actual networks infrastructures.
Unfortunately only big hardware manufacturers like Cisco or Juniper do support this actually. In Europe, BT provider in England deploy it actually.
For speed, there is no real advantage to use MPLS today, because hardware routers have compiled routing tables. This is as fast as MPLS forwarding. On Cisco hardware, (starting with real hardware routers like 7600 series) there is no speed imrovement from classical routing to MPLS forwarding.
As we have now level2 switching functions today even in small chips like Broadcom ones, there are chances that MPLS will never have a big success in the world, because level 3 routing could integrate those chips fastly and replace very costly hardware routers for medium sized provider networks.
There is no need to use Asics to do hardware routing today. FPGA chips can do the same thing for less monney, and they are programmable, so they are almost as flexible than full software solutions.
Mikrotik, why don't you use a small FPGA chips for level 3 routing and filtering, and implement 802.1ah ? This is about 5 $ by chip. Or ask Broadcom to put an FPGA inside their chips ?
With this you will have wire speed for routing, at a fraction of Cisco / Juniper cost, and you will sell your products to almost all the world mid sized providers....