Datacenter Network Virtualization in
Multi-Tenant Environments
8. DFN-Forum Kommunikationstechnologien
Viktor Goldberg, Leibniz-Rechenzentrum, TU München
Florian Wohlfart, TU München Daniel Raumer, TU München
Network Functions Virtualization
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Applications
x86 Hardware
Building the Network Virtualized Datacenter
• • • • • • • •Overlay Network Architecture
• VM traffic encapsulated inside a UDP/IP frame plus VNI identifier
• VNI defines the L2 domain
• encapsulation performed by a VTEP node
• VTEP is a software or physical switch (at the ToR)
Encapsulated frames are routed to the remote VTEP.
• remote VTEP strips the IP/UDP header
• forwards original frame to the local VM
• transparent to the network core, not aware of the VXLAN overlay
• only edge VTEP nodes need to be VXLAN aware
Open vSwitch (OVS)
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Design and Architecture
• • • • controller running in userspace slowpath datapath running in kernel fastpath
Open vSwitch (OVS)
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A Deep Dive
KER
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KER
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KER
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vswitchd ovsdb-srv
ovs-dpctl OpenFlow ovs-vsctl
• routed traffic at the top of rack
• proven and trusted protocol for scale
• mature open standards for interoperability
• standard scalable model for virtualized and non-virtualized solutions
• minimized size of the L2 domain
• no VLAN scaling issues
Building the Network Virtualized Datacenter
Scaling an L3 network for East to West traffic
• running real kernel, switch and application code in a VM
• supports Open vSwitch
Motivation
• multi-tenant environment with two tenants T1 and T2
• overlapping IP networks and addresses
• completly transparent tunneling, even broadcast traffic (like ARP, DHCP)
Network Virtualization Overlays
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Network Virtualization Overlays
S1 – 172.16.116.135
sh ovs-vsctl add-port s1 vtep -- set interface vtep type=vxlan
option:remote_ip=172.16.116.136 option:key=flow ofport_request=10
S2 – 172.16.116.136
sh ovs-vsctl add-port s2 vtep -- set interface vtep type=vxlan
option:remote_ip=172.16.116.135 option:key=flow ofport_request=10
Demo - Interface Configuration
Network Virtualization Overlays
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T1_1 ping 10.0.0.1 T2_1 ping 10.0.0.2
tcpdump –i eth0 [icmp type {0,8}]
tcpdump –i eth0 [icmp type {0,8}]
Conclusion
• simple design of physical environment to provide IP end-to-end connectivity only
• logic should be placed into “Intelligent Edges“, ToR switches like OVS
• logical tenant separation through VXLAN tunneling technologies
Future Work
• identification of services and tenants with specific needs
• deployment of a test environment
• long term goal: NFV rollout and optimization of physical underlay
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