Administrator Guide

VXLAN Hypervisor It is the VTEP that connects the Virtual Machines (VM) to the underlay legacy network to the physical
infrastructure.
Service Node(SN) It is also another VTEP, but it is fully managed by NSX. The purpose of SN is to be the central replication engine for
ooded packets
Legacy TOR It is a TOR switch, which performs routing or switching decisions.
Functional Overview of VXLAN Gateway
The following section is the functional overview of VXLAN Gateway:
1 Provides connectivity between a Virtual server infrastructure and a Physical server infrastructure.
2 Provides the functions performed by a VTEP in a virtual server infrastructure. The functions of a VTEP are:
• VTEP is responsible for creating one or more logical networks.
• VTEP is responsible for identifying and binding a Port and VLAN to a logical network
• VTEP maintains MAC bindings to a VTEP.
• VTEP is typically managed by a network orchestrator. When the device functions as VTEP, VXLAN from VMWare is the network
orchestrator.
• VXLAN communicates with the VTEP using a standard protocol called OvsDb Protocol. The protocol uses the JSON RPC-based
message format.
• The VTEP acts according to the TOR schema dened by VMWare. The solution is very specic to VMWare-based orchestration
platforms and does not work with other orchestration platforms.
VXLAN Frame Format
VXLAN provides a mechanism to extend an L2 network over an L3 network. In short, VXLAN is an L2 overlay scheme over an L3 network
and this overlay is termed as a VXLAN segment. VMs within the same VXLAN segment communicate with each other through a 24–bit ID
called VXLAN Network Identier (VNI). This 24–bit ID allows up to 16 million VXLAN segments to coexist within the same administrative
domain. The VNI scopes the inner MAC frame originated by the VM. This model has over-lapping MAC addresses without trac cross-
over
VXLAN achieves L2 over L3 overlay using the tunneling mechanism. VTEPs are the end points of a tunnel located within the hypervisor on
the server that hosts VMs. The VXLAN frame format is shown in the following gure:
Figure 151. VXLAN Frame Format
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Virtual Extensible LAN (VXLAN)