Concept Guide

VXLAN Header :
• VXLAN Flags : Reserved bits set to zero except bit 3, the rst bit, which is set to 1 for a valid VNI
• VNI: The 24-bit eld that is the VXLAN Network Identier
• Reserved: A set of elds, 24 bits and 8 bits, that are reserved and set to zero .
Frame Check
Sequence (FCS):
Note that the original Ethernet frame's FCS is not included, but new FCS is generated on the outer Ethernet
frame.
Limitations on VXLAN
While conguring a VXLAN, the following conditions apply:
• Hybrid ports are not supported in VXLAN (hybrid port means an interface tagged to one VLAN and untagged to another VLAN).
• The show vxlan vxlan-instance statistics remote-vtep-ip and the show vxlan vxlan-instance
statistics instance commands are not supported in a NSX environment.
• VXLAN is not supported in a stacking setup.
• VXLAN with VRF conguration is not supported.
• Routing over VXLAN is not supported in a controller-based VXLAN setup.
• SNMP and REST API are not supported for VXLAN congurations.
• Multicast over VXLAN is not supported.
• In multicast and broadcast trac, even though the remote VTEP is reachable through the ECMP path, load balancing is not supported.
• Supports only 4 remote vteps through a single interface in a broadcast domain.
– When a fth remote VTEP congured is reachable via the same network port, trac destined to the fth remote VTEP ows to
the rst remote VTEP congured via the same network port. If any of the rst four remote VTEPS congured via the same
network port is removed, trac ow to the fth remote VTEP is not restored. You need to do one of the following to restore trac
ow to fth remote VTEP correctly :
◦ Remove and add the fth remote VTEP again
◦ Flap the next hop reachability to the fth remote VTEP
• Single VNI can be mapped to Single VLAN in both static and NSX controller-based VXLAN. Hence, only 4000 VNIs are supported while
conguring static VXLAN.
• You can map multiple VNIs with multiple VLANs in an NSX-based VXLAN.
• You can congure only one Nuage controller in a VXLAN setup. Nuage controller datapath-learning is not supported.
• In a Nuage controller-based VXLAN deployment, station moves of non-virtualized entities may not work as expected due to a possible
issue in the Nuage contoller.
NOTE
: When more than 15000 learned MAC addresses are synchronized from the Nuage controller to one of the VTEPs, the
SSL connection between the controller and the VTEP aps continuously.
Conguring and Controlling VXLAN from the NSX
Controller GUI
You can congure and control VXLAN from the NSX controller GUI, by adding a hardware device to NSX and authenticating the device.
1 Generate a certicate in your system and add it to the NSX before adding a hardware device for authentication.
To generate a certicate, use the following command:
• crypto cert generate self-signed cert-file flash://vtep-cert.pem key-file flash://vtep-
privkey.pem
To view the certicate, use the following command:
• show file flash://vtep-cert.pem
Virtual Extensible LAN (VXLAN)
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