...
Virtual Extensible LAN (VXLAN) is an overlay network virtualization technology. An overlay network is a virtual network that is built on top of existing network Layer 2 and Layer 3 technologies to support elastic compute architectures. VXLAN makes it easier for network engineers to scale out a cloud computing environment while logically isolating cloud apps and tenants.
VXLAN Technology
VXLAN uses UDP-based encapsulation to tunnel Ethernet frames and transfers original data packets as tunnel payloads. With the outer UDP tunnel, inner payload data can be quickly transferred on the layer 2 and layer 3 networks. To provide the capability of broadcast domain addressing, the VXLAN technology uses layer 3 IP multicast to replace the Ethernet broadcast. Therefore, the broadcast, unknown unicast, and multicast (BUM) packets can be transferred on virtual networks through broadcasting. For more VXLAN details, please read RFC7348.
VXLAN Standards
As shown in Figure 1-1, a VXLAN packet consists of the outer encapsulation and the inner payloads.
...
The below table shows the traffic changes in the case that interfaces vlans in the access side are binded with a vxlan in the network side.
...
Access->Network
...
Access→Access (configure with decapsulation mode) | Access→Network (configure with encapsulation mode) | Network→Access (configure with decapsulation mode) | |
|---|---|---|---|
| none | untag-- |
>tag(PVID) tag-->remain tag | untag- |
->tag(PVID) tag->remain tag | untag-->untag tag-->remain tag |
service-vlan-add | untag-->tag( |
|---|
PVID) tag->remain tag | untag |
- |
- |
>tag( |
PVID) tag- |
service-vlan-add-delete
untag->tag(add pvid)
tag-->untag
untag-->add encapsulation vlan
tag->untag(been deleted)
untag-->tag(add pivd)
>remain tag | untag-->tag(add vxlan-vlan) tag-->double tag(outer layer add |
vxlan-vlan |
untag->tag(add pvid)
tag-->new tag(replaced with pvid)
untag-->add encapsulation vlan
tag->tag(changed to encapsulation vlan)
untag-->tag(add pivd)
tag-->double tag(outer layer add pvid)
service-vlan-delete
) | |
service-vlan-add-delete | untag-->untag tag-->untag |
|---|
untag->untag
tag->untag
untag-->untag tag- |
service-vlan-replace
>untag |
tag-->new tag(replaced with pvid)
untag->untag
tag->tag(changed to encapsulation vlan)
untag-->untag
tag-->remain tag
The below table shows the traffic changes in the case that the interfaces and vlans in the access side are binded with a vxlan in the network side.
Access->Network
Network->Access
tag-->remain tag
tag->remain tag
untag-->untag
tag-->remain tag
service-vlan-add
tag->remain tag
tag->remain tag
(been deleted) | untag-->tag(add vxlan-vlan) tag-->double tag(outer layer add vxlan-vlan) |
service-vlan-add- |
|---|
tag-->untag
tag->untag(been deleted)
replace | untag-->tag( |
|---|
PVID) tag-- |
service-vlan-add-replace
>remain tag | untag→tag(configured VLAN) tag->tag( |
configured VLAN) | untag-->tag(add vxlan-vlan) tag-->double tag(outer layer add vxlan-vlan) |
service-vlan-delete |
|---|
untag-->untag tag-->untag | untag-->untag |
tag |
- |
tag-->new tag(replaced with vxlan-vlan)
tag->tag(changed to encapsulation vlan)
>untag |
tag-->remain tag
...
Access->Network
Network->Access
tag-->remain tag
untag-->untag tag-->remain tag | |
service-vlan- |
|---|
tag->remain tag
tag->remain tag
replace | untag-->tag( |
|---|
tag-->double tag(outer layer add vxlan-vlan)
service-vlan-add-delete
tag-->untag
tag->untag(been deleted)
untag-->tag(add vxlan-vlan)
tag-->double tag(outer layer add vxlan-vlan)
service-vlan-add-replace
tag-->remain tag
tag->tag(changed to encapsulation vlan)
untag-->tag(add vxlan-vlan)
tag-->double tag(outer layer add vxlan-vlan)
service-vlan-delete
tag-->untag
tag->untag
untag-->untag
tag-->remain tag
service-vlan-replace
PVID) tag-->remain tag | untag→tag(configured VLAN) tag->tag(changed to encapsulation vlan) | untag-->untag tag-->remain tag |
VXLAN ECMP
In L2/L3, VXLAN ECMP is supported. Picos supports up to 32-way ECMP.
- The VXLAN ECMP does not need special configuration. It entirely depends on the routing ECMP. The route ECMP configure link: ECMP (Equal-Cost Multipath Routing) Configuration
- PicOS uses info from VXLAN header for hash calculation to ensure better performance.
VXLAN Mac Learning
The VTEP performs source MAC learning on the VNI as a Layer 2 switch.
...
- The all remote VTEP decapsulates the packet and forwards the frame to access port.
Configure to map VLAN to VXLAN VNI Step
VxLAN supported on PicOS L2/L3 switch. To configure Step, pleae see below.
...