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Cisco adds Ethernet VXLAN BGP support to Nexus switches

Old dogs get new SDN overlay tricks

Cisco is giving another nod in the direction of support for open software-defined-network standards, announcing support for BGP EVPN on its Nexus 9000.

BGP EVPN – Border Gateway Protocol, Ethernet Virtual Private Network – is an Internet draft authored by members from Cisco, Juniper, Verizon, AT&T, Alcatel-Lucent and Bloomberg.

The draft marries the ubiquitous BGP – one of the foundation protocols of the Internet – to Ethernet-based VPNs to create an open network virtualisation overlay.

This, Cisco says, provides a control-plane protocol for VXLAN-based overlays.

Deploying BGP-EVPN also fits with OpenStack strategies, the Borg says, allowing users “to automate the creation, provisioning and management of their VXLAN-based overlay environments, including the ongoing management of endpoint address mappings, allowing native workload mobility support”.

If the customer wants to stick with the Cisco environment, they can run it on Nexus 9000 and the company's Application-Centric Infrastructure (ACI) and VXLAN.

The Cisco implementation will support “a range of topologies (spine-leaf, three-tier aggregation, full mesh), as well as interoperate with a wide range of Top of Rack (ToR) switches and WAN equipment”, the company says.

The BGP EVPN draft says it's trying to solve data centre requirements like isolation of traffic between thousands of tenants; providing layer 2 connectivity between a tenant's virtual machines (VMs) within a data centre or between different DCs; and the migration of VMs between different physical ports within the L2 segment.

The protocol learns IP and MAC addresses at the control plane rather than at the data plane, to reduce the learning traffic on the network (unicast and ARP frames).

As this Alcatel-Lucent presentation notes, while MPLS, VPLS and provider backbone bridge (PBB) are proven VPN options, they inherit a legacy approach to the control plane. In particular, they rely on “flooding and learning” to build Layer 2 forwarding databases. ®

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