Hi,
On Oct 20, 2016, at 9:43 AM, steven brock <ef14019@gmail.com> wrote:
Compared to MPLS, a L2 solution with 100 Gb/s interfaces between core switches and a 10G connection for each buildings looks so much cheaper. But we worry about future trouble using Trill, SPB, or other technologies, not only the "open" ones, but specifically the proprietary ones based on central controller and lots of magic (some colleagues feel the debug nightmare are garanteed).
From my perspective, in this day and age, no service provider or campus should really be using any sort of layer 2 protection mechanism in their backbone, if they can help it.
If you had to make such a choice recently, did you choose an MPLS design even at lower speed ?
Yup. 5 or so years ago, and never looked back. Actually, this was in conjunction with upgrading our 1G backbone to a 10G backbone, so it was an upgrade for us in all senses of the word.
How would you convince your management that MPLS is the best solution for your campus network ?
You already did: <snip>
We are not satisfied with the current backbone design ; we had our share of problems in the past: - high CPU load on the core switches due to multiple instances of spanning tree slowly converging when a topology change happens (somehow fixed with a few instances of MSTP) - spanning tree interoperability problems and spurious port blocking (fixed by BPDU filtering) - loops at the edge and broadcast/multicast storms (fixed with traffic limits and port blocking based on threshhold) - some small switches at the edge are overloaded with large numbers of MAC addresses (fixed with reducing broadcast domain size and subnetting)
This architecture doesn't feel very solid. Even if the service provisionning seems easy from an operational point of view (create a VLAN and it is immediately available at any point of the L2 backbone), we feel the configuration is not always consistent. We have to rely on scripts pushing configuration elements and human discipline (and lots of duct-tape, especially for QoS and VRFs).
</snip>
How would you justify the cost or speed difference ?
It’s only more expensive the more big vendor products you use. Sometimes you need to (i.e.: Boxes with big RIB/FIBs for DFZ, or deep buffers), but more and more, people are looking to OCP/White Box Switches [1][2]. For example, assuming a BCM Trident II based board with 48 SFP+ cages and 6 QSFP+ cages, you get a line-rate, MPLS capable 10G port for $65. Or, if you’re like me and hate the idea of breakout cables, you’re at about $100/SFP+ cage, at which points the QSPF+ cages are pretty much free. Software wise, there are lots of vendors. One that I like is IPInfusion’s OcNOS[3] codebase. They are putting a lot of resources into building a service provider feature set (full-blown MPLS/VPLS/EVPN, etc.) for OCP switches. There are others, but last time I looked a couple of years ago, they were less focused on MPLS and more focused on SDN: Cumulus Networks[4], PICA8[5], Big Switch Networks[6].
Thanks for your insights!
[1] https://www.linx.net/communications/press-releases/lon2-revolutionary-develo... [2] http://www.ipinfusion.com/about/press/london-internet-exchange-use-ip-infusion’s-ocnos™-network-operating-system-new-london-in [3] http://www.ipinfusion.com/products/ocnos [4] https://cumulusnetworks.com [5] http://www.pica8.com [6] http://www.bigswitch.com