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Registered: ‎05-26-2011

Innovation: Hybrid Port Mode in GENI Deployments

Today I’m going to briefly talk about a new and unique Brocade NetIron capability called hybrid port mode and how it will be leveraged in GENI network deployments. While this hybrid port mode capability will be deployed in many different network scenarios, the not-so-obvious benefits in GENI deployments are the focus of this blog.

GENI is the Global Environment for Network Innovations. Taken directly from their website:

Evolving technological and social networks, intertwined and worldwide in scope, are rapidly transforming societies and economies. The Global Environment for Network Innovations (GENI), a project sponsored by the National Science Foundation, is open and broadly inclusive, providing collaborative and exploratory environments for academia, industry and the public to catalyze groundbreaking discoveries and innovation in these emerging global networks.

GENI is a virtual laboratory at the frontiers of network science and engineering for exploring future internets at scale. GENI creates major opportunities to understand, innovate and transform global networks and their interactions with society.

Below is a high-level diagram of the inter-connectivity required between “GENI racks”. A GENI rack typically consists of one or more OpenFlow(OF)/Layer-2/Layer-3 switches providing connectivity amongst a bunch of “worker node” computing machines used by the researchers and experimenters. The OF/L2/L3 switches in the GENI rack also provide connectivity to multiple external networks (such as GENI, Internet2, and the Internet). This external connectivity is required for experimentation and collaboration amongst the many GENI researchers.


So, that’s GENI in a nutshell (or should I have said, “GENI in a bottle”?). Now, what exactly is this hybrid port mode capability and what problem does it solve in GENI deployments?

First I need to talk about how most network vendors have implemented OF. Some have OF-only switches that only run OF (no L2, L3/IP, MPLS, etc) on all ports in the switch (except perhaps a management port). If this type of switch is deployed in the GENI rack then the rack will also need to include additional L2 and L3 capable switches. This is because the researchers’ machines may need OF ports to the GENI rack and also L2 and L3 ports to the GENI rack and to other campus computing resources. Furthermore, the GENI racks need OF and L2/L3 ports to provide connectivity to external networks for collaboration with other researchers. The GENI racks can also operate in a “GENI on, GENI off” mode, where OF ports are required when running a specific SDN experiment (aka: GENI on) and when a non-SDN experiment is run or when the rack is idle (aka: GENI off), it needs L2 or L3 ports. This will result in multiple switches in the rack and will double the port density of the rack since some switches are OF-only and some switches are L2/L3-only.

Alternately, some vendors provide a hybrid switch mode capability. This allows the switch to be divided up by port type; where there is a configured group of OF ports and a separate group of L2 or L3 ports. This may reduce the number of switches required in the GENI rack but does not reduce the port density of the rack. Due to the requirement to have OF and L2/L3 ports, this still results in a doubling of the port density in the rack. Even in this case, additional switches may still be required in the rack just to cover the higher port density requirements.

While we’re on this topic I should point out that Brocade has been supporting OpenFlow v1.0 since NetIron Software Release 5.4. Here is a link to the NetIron 5.4 Software Configuration Guide for Openflow.

Brocade not only provides this hybrid switch mode capability; but more importantly, now provides a hybrid port mode capability. This capability currently allows all ports on the switch to operate in OF mode and L3 mode, simultaneously. In other words, each port can be enabled to run the OF protocol and IP protocols concurrently! This allows a GENI rack that includes Brocade switches to use the OF protocol and IP protocols simultaneously on any of the Brocade switch ports. This not only reduces the port density of the rack but could reduce the need for additional switches. For example, a single MLXe-4 switch can provide up to 96 1GbE ports or 96 10GbE ports in a single chassis. You can also have a mix of 1GbE and 10GbE ports.

For configuration details on this new and powerful hybrid port mode capability, please refer to the NetIron 5.4b Software Update Guide. As we continue to innovate in this area, we will be adding additional protocol support for hybrid port mode.

So, the end result of leveraging this unique Brocade capability in GENI network deployments is the ability to operate in the “GENI on, GENI off” modes without the need for additional port density or having to re-cable ports (ouch!) to run multiple protocols simultaneously.

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