H3C S5560X-EI Series, Руководство по настройке

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VXLAN overview
Virtual eXtensible LAN (VXLAN) is a MAC-in-UDP technology that provides Layer 2 connectivity
between distant network sites across an IP network. VXLAN is typically used in data centers and
campus access networks for multitenant services.
VXLAN provides the following benefits:
•
Support for more virtual switched domains than VLANs —Each VXLAN is uniquely
identified by a 24-bit VXLAN ID. The total number of VXLANs can reach 16777216 (2
24
). This
specification makes VXLAN a better choice than 802.1Q VLAN to isolate traffic for user
terminals.
•
Easy deployment and maintenance —VXLAN requires deployment only on the edge devices
of the transport network. Devices in the transport network perform typical Layer 3 forwarding.
The device supports only IPv4-based VXLAN. IPv6-based VXLAN is not supported.
VXLAN network model
As shown in Figure 1 , a VXLAN is a virtual Layer 2 network (known as the overlay network) built on
top of an existing physical Layer 3 network (known as the underlay network). The overlay network
encapsulates inter-site Layer 2 frames into VXLAN packets and forwards the packets to the
destination along the Layer 3 forwarding paths provided by the underlay network. The underlay
network is transparent to tenants, and geographically dispersed sites of a tenant are merged into a
Layer 2 network.
The transport edge devices assign user terminals to different VXLANs, and then forward traffic
between sites for user terminals by using VXLAN tunnels. Supported user terminals include PCs,
wireless terminals, and user terminals on servers.
The transport edge devices are VXLAN tunnel endpoints (VTEP).
An H3C VTEP uses VSIs and VXLAN tunnels to provide VXLAN services.
•
VSI —A virtual switch instance is a virtual Layer 2 switched domain. Each VSI provides
switching services only for one VXLAN. VSIs learn MAC addresses and forward frames
independently of one another. User terminals in different sites have Layer 2 connectivity if they
are in the same VXLAN.
•
VXLAN tunnel —Logical point-to-point tunnels between VTEPs over the transport network.
Each VXLAN tunnel can trunk multiple VXLANs.
VTEPs encapsulate VXLAN traffic in the VXLAN, outer UDP, and outer IP headers. The devices in
the transport network forward VXLAN traffic only based on the outer IP header.