This chapter provides
an overview of Cisco Virtual Topology System (VTS). It has the following
The Cisco Virtual
Topology System (VTS) is a standards-based, open, overlay management and
provisioning system for data center networks. It automates DC overlay fabric
provisioning for both physical and virtual workloads.
Cisco VTS provides a
network virtualization architecture and software-defined networking (SDN)
framework that meets the requirements of multitenant data centers for cloud
services. It enables a policy-based approach for overlay provisioning.
Cisco VTS automates
complex network overlay provisioning and management tasks through integration
with cloud orchestration systems such as OpenStack and VMware vCenter and
abstracts out the complexity involved in managing heterogeneous network
environments. The solution can be managed from the embedded Cisco VTS GUI or
entirely by a set of northbound Representational State Transfer (REST) APIs
that can be consumed by orchestration and cloud management systems.
Cisco VTS provides:
standards based solution
Cisco Nexus 5000,
7000, and 9000 Series Switches. For more information, see Supported Platforms
Cisco VTS 2.2 Installation
(Virtual Topology Forwarder [VTF])
Cisco VTS architecture
has two main components: the Policy Plane and the Control Plane. These perform
core functions such as SDN control, resource allocation, and core management
Figure 1. Cisco VTS Architecture
Policy Plane: The policy
plane enables Cisco VTS to implement a declarative policy model designed to
capture user intent and render it into specific device-level constructs. The
solution exposes a set of modular policy constructs that can be flexibly
organized into user-defined services for use cases across service provider and
cloud environments. These policy constructs are exposed through a set of REST
APIs that can be consumed by orchestrators and applications to express user
intent, or instantiated through the Cisco VTS GUI. Policy models are exposed as
system policies or service policies.
allow administrators to logically group devices into pods within or across data
centers to define Admin Domains with common system parameters (for example,
BGP-EVPN control plane with distributed Layer 2 and 3 gateways).
module maintains a database of the available physical entities (for example,
data center interconnect [DCI] routers and top-of-rack leaf, spine, and
border-leaf switches) and virtual entities (for example, VTFs) in the Virtual
Topology System domain. The database also includes interconnections between
these entities and details about all services instantiated within a Virtual
Topology System domain.
management module manages all available resource pools in the Virtual Topology
System domain, including VLANs, VXLAN Network Identifiers (VNIs), IP addresses,
and multicast groups.
Control Plane: The
control plane module serves as the SDN control subsystem that programs the
various data planes including the VTFs residing on the x86 servers, hardware
leafs, DCI gateways. The control plane hosts the Cisco IOS XRv Software
instance that provides route peering capabilities between the DCI gateways or
to a BGP route reflector. Cisco IOS XRv is the virtualized version of Cisco IOS
XR Software. The control plane enables an MP-BGP EVPN-based control plane for
VXLAN overlays originating from leafs or software VXLAN tunnel endpoints
The device management module enables device configuration and
management capabilities within Virtual Topology System, with multiprotocol
support to support a multivendor environment.
Cisco VTS solution provides a l2/l3 software switch that can act as a
software VTEP and is called Virtual Topology forwarder (VTF). Cisco VTS can be
deployed with a Virtual Topology Forwarder (VTF). VTF is a lightweight,
multitenant software data plane designed for high performance packet processing
on x86 servers. VTF uses Vector Packet Processing (VPP). VPP is a full-featured
networking stack with a software forwarding engine. VTF leverages VPP
technology and Intel Data Path Development Kit (DPDK) for high performance
Layer 2 (L2), Layer 3 (L3), and VXLAN packet forwarding.
VTF allows Cisco VTS
to terminate VXLAN tunnels on host servers by using the VTF as a Software VXLAN
Tunnel Endpoint (VTEP). Cisco VTS also supports hybrid overlays by stitching
together physical and virtual endpoints into a single VXLAN segment.
VTF is deployed as a
virtual machine to deliver a high-performance software data plane on a host
System High Availability
The Virtual Topology
System solution is designed to support redundancy, with two solution instances
running on separate hosts in an active-standby configuration.
During initial setup,
each instance is configured with both an underlay IP address and a virtual IP
address. Virtual Router Redundancy Protocol (VRRP) is used between the
instances to determine which instance is active.
data is synchronized with the standby instance after each transaction to help
ensure consistency of the control-plane information to accelerate failover
after a failure. BGP peering is established from both Virtual Topology System
instances for the distribution of tenant-specific routes. During the
switchover, nonstop forwarding (NSF) and graceful restart help ensure that
services are not disrupted.
Availability section of the
Cisco VTS 2.2 Installation
Guide for the detailed procedure about setting up high availability.