Tag: nexus7k

Configure your multicast WAN for OTV

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It is easy to find design and configuration guides about OTV implementations on Nexus 7000 switches, ASR and CSR routers. But it is much harder to find some information about the requirements for your WAN.
Please read my previous blog posts about OTV here, here, here and here. I’ll cover the OTV device configurations in those posts. But for now, lets start with the DCI WAN for OTV.
First of all, there are two OTV deployment options:

  • Unicast mode
  • Multicast mode

The WAN requirements in unicast mode are simple: deliver unicast connectivity between the join interfaces of all OTV edge devices. This is just a simple straight forward configuration, I will not cover this in this blog post.
The multicast deployment is a bit harder to configure and requirements are less easier to find. This blog post will cover the required WAN configuration in a multicast deployment. In this particular scenario, we use dark fiber / DWDM connections as DCI to get a more clear understanding about the requirements and configuration.
First, a drawing to get a view on this deployment scenario:

OTV WAN multicast layout

OTV WAN multicast layout


This blog will provide you with the most easiest way to get your OTV multicast deployment up and running. There are some more finetune options available, but that will not be covered in this blog.
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Cisco Nexus 7000 OTV configuration

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Another post, this time about the basic OTV configuration on a Nexus 7000.
The OTV configuration has the be made on a different switch (or VDC) where no SVI’s are configured for the VLAN’s you want to extend to the other site.
First of all some terminology:
  • Edge device: This device performs layer 2 activities (to the internal network) and OTV transportation to the other site(s).
  • Transport network: This is the network (can be layer 3) that connects all the sites. This is your WAN connection, possible managed by your service provider.
  • Join interface: This is the uplink interface on the edge device that is connected to the transport network.
  • Internal interface: This is the interface on the edge device that is connected to the internal network.
  • Overlay interface: This is a logical interface, with support for multi access, multicast. This interface encapsulates layer 2 frames in IP headers (also ‘MAC routing’)
  • Overlay network: A logical network that connects all sites together and uses MAC routing for interconnecting the sites.
  • Site: Your (layer 2) network on a location. In most cases, this is one of your datacenters.