Solving the Data Plane Performance Challenges for NFV

6WIND and Dell: CloudNFV™ partners

dell_cloud_NFV

As many readers will know, both 6WIND and Dell are two of the founding members of the CloudNFV initiative, announced on August 14th. CloudNFV is a group of vendors dedicated to creating a technical framework and demonstration platform for Network Functions Virtualization (NFV) based on cloud computing and Software Defined Networking (SDN) technologies in a multi-vendor environment.

Through our work together on the CloudNFV solution, we’ve developed a strong understanding of the key data plane challenges associated with NFV deployments in general.

In this post, I’ll explain these challenges and outline how they are addressed by the 6WINDGate™ networking software, running on Dell server platforms.

Leveraging technology proven in physical infrastructure

6WIND is uniquely positioned to provide data plane solutions for NFV because 6WINDGate is already widely used in physical networking equipment deployed in telecom infrastructure worldwide. Through high-performance packet processing, 6WINDGate enables service providers to maximize the number of subscribers supported per blade, in applications such as LTE Evolved Packet Core (EPC) equipment.

Over the past couple of years, we’ve extended our technology to incorporate solutions for networking performance bottlenecks associated with virtualization elements such as hypervisors and virtual switches, so that TEMs and service providers can now adopt our software, already proven in physical networking implementations, to maximize the performance of their Virtual Networking Functions (VNFs) in NFV deployments.

6WINDGate fits in two places within an NFV deployment: first, it maximizes the switching performance of the virtual switch that provides high-bandwidth network traffic to the VNFs running in Virtual Machines (VMs), thereby increasing the aggregated bandwidth delivered to the VMs and, second, it accelerates the data plane performance of each VNF.

Data plane performance challenges in NFV

At this point in the evolution of NFV, most vendors are working on aspects relating to network management and orchestration. This emphasis makes perfect sense given the extreme complexity of legacy telecom networks and the challenges of migrating these control-related systems to a completely new software-based architecture. And, of course, the concept of “Carrier Grade reliability” reflects the expectations that we all have for the constant availability of network services.

Additionally, though, there are fundamental data plane issues that must be addressed in order for any NFV implementation to be cost-effective.

COTS Server DiagramThe first bottleneck is the software virtual switch (vSwitch) running on the server platform. This vSwitch must provide sustained, aggregated high-bandwidth network traffic to the Virtual Network Functions (VNFs). At the same time, the performance of (secure) VM-to-VM communications must be maximized.

Both these requirements are necessary to ensure that NFV deployments are cost-effective when compared with traditional network infrastructure based on physical switches.

Unfortunately, standard virtual switches such as the open-source Open vSwitch (OVS) do not deliver adequate performance or scalability to address these needs.

The second bottleneck is the performance of the VNFs themselves. Service providers will need their VNFs to deliver cost-performance that is comparable to that achieved by equivalent physical implementations. Otherwise, their NFV deployments won’t be cost-effective and there will be no ROI justification for a transition to NFV.

VNF performance, though, is constrained by two factors. One is the poor performance and limited scalability of standard Operating System networking stacks. The other is the limitation on bandwidth for communication outside the VM that is imposed by standard hypervisors.

 6WIND’s solutions

Within NFV deployments, the 6WINDGate networking software addresses the two performance bottlenecks described above.

NFVFirst, 6WINDGate accelerates the virtual switch that switches network traffic to the VMs in which the VNFs are instantiated.

When used to accelerate the standard Open vSwitch (OVS), 6WINDGate delivers a 10x improvement in switching performance. This typically enables the instantiation of a large number of VNFs per blade, each of which requires sustained high-bandwidth traffic.

As part of improving OVS performance, 6WINDGate also accelerates secure tunneling protocols such as IPsec, GRE, NVGRE, VLAN and VxLAN which are required OVS features for supporting high-bandwidth, secure VM-to-VM traffic.

Second, 6WINDGate accelerates the performance of VNFs. Thanks to its fast path data plane architecture, 6WINDGate typically delivers 10x the performance of the standard Linux networking stack, with no changes required to the Linux kernel. This performance scales linearly with the number of cores configured to run the fast path. 6WINDGate includes a comprehensive set of networking protocols, for example PPP (used in a virtual Broadband Access Server or “vBRAS”), firewall and IKE (used in security gateways) and TCP termination (used in WAN Optimization appliances).

As a result of optimizations for virtualized environments, 6WINDGate delivers comparable performance running under a hypervisor to that achieved when running in a physical implementation. This enables service providers to obtain best-in-class cost-performance from their VNFs, such as firewalls and security gateways.

In the specific CloudNFV use case shown in the diagram, 6WINDGate runs within the KVM hypervisor and Linux, under the control of OpenStack, on the Dell server that comprises the overall hardware deployment platform.

Open standards and compatibility with legacy software

When 6WINDGate is used to accelerate OVS (the first bottleneck described above), no changes are required to the standard OVS code itself. 6WINDGate intercepts packets that would normally be processed in the (slow) OVS data plane, processing them in the 6WINDGate data plane instead.

In the case of VNF acceleration (bottleneck #2), 6WINDGate is fully compatible with standard Linux networking APIs (Netfilter, Netlink etc.). This means that no modifications are required to the VNF applications themselves in order to take advantage of the performance improvement provided by 6WINDGate.

Finally, 6WINDGate is fully-compatible with the OpenFlow protocol used in many NFV architectures.

Demos coming soon

CloudNFV demonstrations are planned for various upcoming industry events. We look forward to participating and hope to see you there!

 

Charlie Ashton

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