Network Packet Broker VXLAN Header Stripping in Original Packet and
Metadata
VxLAN Message Parsing
Below is vxlan protocol message, the white part is the virtual
machine to send a message (layer 2 frame, contains the MAC head
head and head of the transport layer, IP packet), adding the vxlan
head for vxlan kept related content, in the front is a standard UDP
protocol header (UDP, IP and MAC head) is used to transmit a
message on the underlying network.
The outermost UDP protocol packets are used for transmission on the
underlying network, which is the basis of the communication between
vtep and each other.
In the middle is the VXLAN header. After the vtep receives the
message, the previous UDP protocol part is removed and the logic of
the VXLAN is processed according to this part, which is mainly sent
to the final virtual machine according to the VNI.
Inside is the original message, the message contents seen by the
virtual machine.
The VxLAN protocol contains 50 bytes more than the original
message, which reduces the proportion of network links that
transmit valid data.The most important vxlan header is the VNID
field, while the remaining fields are reserved primarily for future
extensions and are currently left to different vendors to add their
own functionality with.
Required Information for a Complete VxLAN Message:
Inner Layer Message:
The virtual machines communicating with each other either directly
use IP addresses or have already obtained each other's IP addresses
through DNS and so the network layer addresses are already
known.The virtual machine of the same network needs to communicate
and also needs to know the MAC address of the other virtual
machine. Vxlan needs a mechanism to realize the function of
traditional network ARP.
VxLAN Head:
You only need to know about VNI, which is usually configured
directly on vtep, either by pre-programmed write death or
automatically generated from internal messages.
The UDP Header:
The most important are the source and destination ports, which are
generated and managed by the system, and the destination ports,
such as port 4789 specified by IANA.
IP header:
The IP header is concerned with the IP addresses of both sides of
the vtep, the source address can be easily determined, the
destination address is the address of the virtual machine the IP
address of the host vtep, and this also needs to be determined in
some way.
The MAC Header:
If the vtep IP address is determined, the MAC address can be
obtained in the classic ARP way.
VXLAN Network Structure
NVE(Network Virtrualization Edge virtual Edge node) is a functional
entity to realize Network virtualization. After packets in VM are
encapsulated by NVE, L2 virtual Network can be established between
NVE based on L3 Network.Both the VSwitch on the network device
entity and the VSwitch on the server entity can act as NVE.
VTEP is the endpoint of the VXLAN tunnel, which is encapsulated in NVE
and used for the encapsulation and unencapsulation of VXLAN
messages.VTEP is connected to the physical network, and the address
assigned is the physical network IP address.The source IP address
in VXLAN message is the VTEP address of the node, and the
destination IP address in VXLAN message is the VTEP address of the
node. A pair of VTEP addresses correspond to a VXLAN tunnel.
VNI (VXLAN Network Identifier) : VXLAN Network Identifier (VNI) is
similar to VLAN ID and is used to distinguish VXLAN segments.
Virtual machines of different VXLAN segments cannot communicate
with each other directly on the second layer.A VNI represents a
tenant, even if multiple end users belong to the same VNI.VNI
consists of 24 bits and supports up to 16M ((2^24-1)/1024^2)
tenants.
VAP (Virtual Access Point) : the VAP of Virtual Access Point is
unified into a two-layer sub-interface for accessing data
packets.Different stream packages are configured for the two layer
sub-interfaces, so different data packets can be connected to
different two layer sub-interfaces.
Recommend Network Packet Broker for VXLAN Header Stripping in
Original Packet and Metadata
NT-FTAP-32QCX
Network TAP NPB.pdf
