Cisco Nexus 7000 Series OTV Quick Start Guide
This guide describes the basic configuration for Overlay Transport Virtualization (OTV) on Cisco NX-OS devices. OTV is a MAC-in-IP method that extends Layer 2 connectivity across a transport network infrastructure. OTV uses MAC address-based routing and IP-encapsulated forwarding across a transport network to provide support for applications that require Layer 2 adjacency, such as clusters and virtualization. You deploy OTV on the edge devices in each site.Related Information
Configuring an OTV Network
This procedure provides a step-by-step walkthrough of how to configure an OTV edge device. This procedure includes the configuration for a physical interface that acts as the join interface, and a VLAN that is extended over the overlay network. This procedure should be applied to each OTV Edge Device.
A basic OTV configuration requires IP connectivity of the OTV Edge Device to the transport network connecting all OTV edge devices. Also, VLANs that will be extended using OTV have to be configured on the OTV edge devices. Once these prerequisites are fulfilled, you can configure OTV.
Configuring a Physical InterfaceProcedure
This procedure shows how to configure a physical interface for IP connectivity to the IP transport network.
What to Do Next
You must configure static or dynamic routing and enable the interface with the no shutdown command.
Configuring a VLAN
Configuring OTVBefore You BeginProcedure
Ensure that you have configured a physical interface that provides connectivity to the IP core and that you have configured the VLANs that will be extended over the OTV network.
What to Do Next
You need to enable the interface with the no shutdown command.
Configuration Examples for OTV
This example displays how to configure a basic OTV network that uses the configuration default values:!Configure the physical interface that OTV uses to reach the ! DCI transport infrastructure interface ethernet 2/1 ip address 192.0.2.1/24 ip igmp version 3 no shutdown !Configure the VLAN that will be extended on the overlay network ! and the site-vlan vlan 2,5-10 ! Configure OTV including the VLANs that will be extended. feature otv otv site-vlan 2 otv site-identifier 256 interface Overlay1 otv control-group 126.96.36.199 otv data-group 188.8.131.52/28 otv join-interface ethernet 2/1 !Extend the configured VLAN otv extend-vlan 5-10 no shutdown
Load Balancing Example
Basic OTV Network
The following example displays how to configure load balancing on two edge devices in the same site:Edge Device 1 interface ethernet 2/1 ip address 192.0.2.1/24 ip igmp version 3 no shutdown vlan 5-10 feature otv otv site-identifier 256 interface overlay 1 otv control-group 184.108.40.206 otv data-group 220.127.116.11/29 otv join-interface ethernet 2/1 otv extend-vlan 5-10 no shutdown Edge Device 2 interface ethernet 1/1 ip address 192.0.2.16/24 ip igmp version 3 no shutdown vlan 5-10 feature otv otv site-identifier 256 interface overlay 2 otv control group 18.104.22.168 otv data-group 22.214.171.124/29 otv join-interface ethernet 1/1 otv extend-vlan 5-10 no shutdown
Verifying the OTV Configuration
To display the OTV configuration, perform one of the following tasks:
show running-configuration otv [all]
Displays the running configuration for OTV.
show otv overlay [interface]
Displays information about overlay interfaces.
show otv adjacency [detail]
Displays information about the adjacencies on the overlay network.
show otv [overlay interface] [vlan [ vlan-range] [authoritative | detail]]
Displays information about VLANs that are associated with an overlay interface.
show otv site [ all]
Displays information about the local site.
show otv [route [interface [neighbor-address ip-address]] [vlan vlan-range] [mac-address]]
Displays information about the OTV routes.
show mac address-table
Displays information about MAC addresses.
Default Settings for OTV
This table lists the default settings for OTV parameters.
Table 1 Default OTV Parameter Settings
ARP and ND suppression
IS-IS hello interval
IS-IS hello multiplier
IS-IS CSNP interval
IS-IS LSP interval
Licensing Requirements for OTV
Prerequisites for OTV
OTV has the following prerequisites:
- Globally enable the OTV feature.
- Enable IGMPv3 on the join interfaces.
- Ensure connectivity for the VLANs to be extended to the OTV edge device.
- If you configure VDCs, install the Advanced Services license and enter the desired VDC (see the Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide).
Guidelines and Limitations for OTV
OTV has the following configuration guidelines and limitations:
- If the same device serves as the default gateway in a VLAN interface and the OTV edge device for the VLANs being extended, configure OTV on a device (VDC or switch) that is separate from the VLAN interfaces (SVIs).
- An overlay interface will only be in an up state if the overlay interface configuration is complete and enabled (no shutdown). The join interface has to be in an up state.
- Configure the join interface and all Layer 3 interfaces that face the IP core between the OTV edge devices with the highest maximum transmission unit (MTU) size supported by the IP core. OTV sets the Don't Fragment (DF) bit in the IP header for all OTV control and data packets so the core cannot fragment these packets.
- Only one join interface can be specified per overlay. You can decide to use one of the following methods:
- If your network includes a Cisco Nexus 1000V switch, ensure that switch is running 4.0(4)SV1(3) or later releases. Otherwise, disable Address Resolution Protocol(ARP) and Neighbor Discovery (ND) suppression for OTV.
- The transport network must support PIM sparse mode (ASM) or PIM-Bidir multicast traffic.
- OTV is compatible with a transport network configured only for IPv4. IPv6 is not supported.
- Do not enable PIM on the join-interface.
- Do not configure OTV on an F-series module.
- Ensure the site identifier is configured and is the same for all edge devices on a site. OTV brings down all overlays when a mismatched site identifier is detected from a neighbor edge device and generates a system message.
- Any upgrade from an image that is earlier than Cisco NX-OS 5.2(1) to an image that is Cisco NX-OS 5.2(1) or later in an OTV network is disruptive. A software image upgrade from Cisco NX-OS 5.2(1) or later to Cisco NX-OS 6.0(1) is not disruptive.
- You must upgrade all edge devices in the site and configure the site identifier on all edge devices in the site before traffic is restored. An edge device with an older Cisco NX-OS release in the same site can cause traffic loops. You should upgrade all edge devices in the site during the same upgrade window. You do not need to upgrade edge devices in other sites as OTV interoperates between sites with different Cisco NX-OS versions.
Obtaining Documentation and Submitting a Service Request
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