Quanta Cloud Technology QuantaMesh QNOS5, Configuration Manual

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For incoming IPv4 packets, the DSCP/TOS value from the incoming IPv4 header is copied into
the outer IPv4 header’s DCSP/TOS field during encapsulation. Otherwise, the DSCP/TOS value
is set to 0.
9.6.2.11. Packet Forwarding
The gateway forwards all packets in hardware. There is no software forwarding.
9.6.3. VXLAN Configuration Examples
With virtualization technology emerging such as VMware’s vSphere, it provides the ability to generate
virtual machines(VMs) in a server. A powerful server is able to provide lots of VMs service. When VMs and
server grow, VM mobility domain is limited by IP subnetting becomes a issue in data center. VXLAN is layer
2 tunneling feature overcomes IP subnetting limitations. It enables IT administrator to move VMs to any
server in the data center, regardless of the data center’s subnetting scheme. VXLAN provides the ability as
Layer 2 VLAN feature but also be able to provide connectivity extension across the Layer 3 boundary. It is
suitable for the large-scale virtualized and multitenant data center designs over a shared common physical
infrastructure.
For crossing the Layer 3 network, VXLAN uses MAC-in-UDP encapsulation scheme. The original Layer 2
frame are added a VXLAN header and is encapsulated in a IP UDP packet. With this MAC-in-UDP
encapsulation, VXLAN tunnels Layer 2 network over Layer 3 network.
The difference between VLAN and VXLAN:

VLANs uses a 12-bit VLAN ID to address Layer2 segments, only 4096 VLANs.

VXLAN uses a 24-bit segment ID known as the VXLAN network identifier (VNI), totally
providing 16 million VXLAN segments to coexist in the same administrative domain.

When VLAN cooperate with STP for avoiding loop issue, it causes half of network links in a
network are blocked.

VXLAN packet are transferred through L3 network based on MAC-in -UDP encapsulation
scheme, it has better utilization of available network paths. It also can take the advantage
of ECMP (equal-cost multipath) routing and LACP (Link aggregation) to best the network
design.
Feature 802.1Q VLAN VXLAN
Number of VLAN support
4K VLAN 16+ million VLAN
Network packet size 1522 or jumbo frame Add 50 bytes for VXLAN header
Multicast requirements N/A Need Multicast Support
PIM-SM, PIM-DM, Bi-direction