Hi, > On Oct 20, 2016, at 9:43 AM, steven brock <[email protected]> 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-development [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
