Cisco Nexus 1000V Quick reference guide

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Cisco Nexus 1000V Switch for
Microsoft Hyper-V
Version 1
Deployment Guide
July 2013
Deployment Guide

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What You Will Learn................................................................................................................................................ 4
Audience................................................................................................................................................................... 4
Overview...................................................................................................................................................................4
Cisco Nexus 1000V Switch Components .............................................................................................................. 4
Template-Based Network Policy............................................................................................................................ 5
Microsoft Hyper-V Networking ............................................................................................................................... 6
Microsoft SCVMM Networking................................................................................................................................ 7
Switch Extension Managers..................................................................................................................................7
Logical Switch....................................................................................................................................................... 8
Port Classifications and Virtual Machine Networks...........................................................................................10
Port Classifications .............................................................................................................................................10
Logical Network and Network Sites....................................................................................................................12
Virtual Machine Networks ...................................................................................................................................13
IP Address Pools ................................................................................................................................................16
Cisco Nexus 1000V Switch Concepts and Components....................................................................................16
Cisco NX-OS Software .......................................................................................................................................16
Virtual Supervisor Module................................................................................................................................... 17
VSM Interfaces............................................................................................................................................... 17
Control Interface.............................................................................................................................................18
Management Interface...................................................................................................................................18
Packet Interface.............................................................................................................................................18
Virtual Ethernet Module ......................................................................................................................................18
VSM-to-VEM Communication............................................................................................................................. 19
Cisco Nexus 1000V Switch Installation ...............................................................................................................24
Cisco Nexus 1000V Switch Features...................................................................................................................25
Switch Forwarding .............................................................................................................................................. 25
MAC Address Learning.......................................................................................................................................25
Loop Prevention..................................................................................................................................................26
Switch Port Interfaces.........................................................................................................................................27
Opaque Data ...................................................................................................................................................... 27
Port Profiles ...........................................................................................................................................................28
Virtual Ethernet Port Profiles ..............................................................................................................................28
Ethernet Port Profiles..........................................................................................................................................29
Network Segments..............................................................................................................................................30
Dynamic Port Profiles .........................................................................................................................................31
System Network Segments.................................................................................................................................31
Policy Mobility.....................................................................................................................................................32
Licensing................................................................................................................................................................32
Cisco Nexus 1000V Switch Network Design.......................................................................................................33
Deployment Topology 1: Recommended............................................................................................................ 33
Management Microsoft Hyper-V Clusters and Hosts.....................................................................................33
VSM High Availability.....................................................................................................................................34
Layer 3 Mode ................................................................................................................................................. 34
Data Virtual Machine Cluster .........................................................................................................................34
Management, Live Migration, and Cluster Traffic...........................................................................................34
Deployment Topology 2: For Customers with Limited pNICs per Microsoft Hyper-V Host.................................35

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Deploying Cisco Nexus 1000V on Cisco Unified Computing System...............................................................35
Cisco Virtual Interface Card................................................................................................................................36
Service Profile Design ........................................................................................................................................36
Quality of Service................................................................................................................................................38
Upstream Switch Connectivity............................................................................................................................. 39
Standard PortChannel ........................................................................................................................................40
LACP Offload...................................................................................................................................................... 40
Special PortChannel...........................................................................................................................................41
vPC-HM MAC Address Pinning......................................................................................................................41
vPC-HM Subgroups .......................................................................................................................................43
Load Balancing...................................................................................................................................................43
Source-Based Hashing.......................................................................................................................................44
Flow-Based Hashing...........................................................................................................................................44
Network-State Tracking ......................................................................................................................................44
Cisco Nexus 1000V Switch for Microsoft Hyper-V Sample Configuration .......................................................45
Conclusion.............................................................................................................................................................47
For More Information............................................................................................................................................. 47

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What You Will Learn
This document provides design and configuration guidance for deployment of the Cisco Nexus®1000V Switch for
Microsoft Hyper-V. For detailed installation and configuration documentation, refer to the respective Cisco®
documentation at http://www.cisco.com/en/US/products/ps13056/index.html.
Audience
This document is intended for network architects, network engineers, virtualization administrators, and server
administrators interested in understanding the deployment of the Cisco Nexus 1000V Switch for Microsoft Hyper-
V.
Overview
When server virtualization is implemented, the edge of the network is pushed from the traditional location in the
network access layer, implemented in physical switches, to the virtual network access layer that is implemented in
software in the server hypervisor. The Cisco Nexus 1000V Switch is an intelligent virtual network access layer
switch that runs Cisco NX-OS Software, Cisco’s data center operating system that runs on all Cisco data center
products. Operating inside the Microsoft Hyper-V hypervisor, the Cisco Nexus 1000V supports Cisco Virtual
Network Link (VN-Link) server virtualization technology to provide:
●Policy-based virtual machine connectivity
●Mobile virtual machine security and network policy
●Nondisruptive operating model for your server virtualization and networking teams
When server virtualization is implemented in the data center, servers and virtual machines are not managed the
same way as physical servers. Server virtualization is treated as a special deployment, leading to longer
deployment time, with more coordination needed among server, network, storage, and security administrators.
With the Cisco Nexus 1000V, you have a consistent networking feature set and configuration and provisioning
model for both the physical and the virtual networks. Virtual machine networks can use the same network
configuration, security policy, diagnostic tools, and operating models as physical server deployments that are
connected to physical switches. This unified approach provides faster deployment and troubleshooting and makes
the administration of virtualization environments essentially the same as for nonvirtualized deployments.
Developed in close collaboration with Microsoft, the Cisco Nexus 1000V Switch is certified by Microsoft and
integrates with Microsoft Windows Server and Microsoft System Center Virtual Machine Manager (SCVMM).
You can use the Cisco Nexus 1000V to manage your virtual machine connectivity with confidence in the integrity
of the server virtualization infrastructure.
Cisco Nexus 1000V Switch Components
Cisco Nexus 1000V Switches have two main components:
●Virtual supervisor module (VSM)
●Virtual Ethernet module (VEM)
The VSM provides the switch control and management plane, and the VEM provides the data plane for the switch
(Figure 1). The VSM can run as a virtual machine on any Microsoft Hyper-V host or as a virtual service node on
the Cisco Nexus 1010 and 1110. The VEM runs as a plug-in (extension) to the Microsoft Hyper-V switch in the
hypervisor kernel, providing switching between virtual machines.

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Cisco Nexus 1000V sees the VSMs and VEMs as modules. In the current release, a single VSM can manage up
to 64 VEMs. The VSMs are always associated with slot numbers 1 and 2 in the virtual chassis. The VEMs are
sequentially assigned to slots 3 through 66 based on the order in which their respective hosts were added to the
Cisco Nexus 1000V Switch.
The Cisco Nexus 1000V Switch provides Layer 2 switching, advanced networking functions (security and
monitoring), and a common network management model for Microsoft Hyper-V servers by implementing a
forwarding extension for the Microsoft Hyper-V Extensible Switch. For more information about Microsoft’s
Extensible Switch architecture, refer to the Microsoft documentation at http://technet.microsoft.com/en-
us/library/hh831452.aspx.
Microsoft strongly recommends the use of Microsoft SCVMM as a centralized platform for managing Compute,
Network and Storage resources in the data center. Cisco Nexus 1000V integrates with Microsoft SCVMM 2012
SP1 to allow the virtualization administrator to deploy virtual machines to the virtual access layer. The server and
virtualization teams must deploy Microsoft SCVMM to use Cisco Nexus 1000V to manage virtual networking.
Note: Cisco Nexus 1000V integrates with Microsoft SCVMM SP1 UR2 Version 3.1.6020.0 and later. Verify that
you are running the minimum required Microsoft SCVMM version before installing Cisco Nexus 1000V.
Figure 1. Cisco Nexus 1000V Switch Components
Template-Based Network Policy
A unique aspect of the Cisco Nexus 1000V is the way that network policy is defined and deployed. Today, when
an application is deployed on a physical server, the upstream network switches are configured. VLANs and
network policies are applied to the physical switches to help ensure that the application and host run securely and
are highly available. For Cisco switches, this management model requires administrators to enter configuration
mode and apply a series of switch commands that define the interface configuration.
Often, identical configurations are needed on multiple interfaces of the same switch or on different switches. This
management model requires server administrators to depend on network administrators to reconfigure the
network each time a server is brought online. This process can create unnecessary delays in deployment of new

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servers. When this model is extended to virtual machines, which are deployed on a larger scale than physical
hosts, it leads to longer deployment times.
The Cisco Nexus 1000V provides an excellent and improved management and configuration model to manage
virtual switches and virtual network policy. In this model, network administrators define a network policy template
that virtualization or server administrators can apply to all virtual machines that require the same network policy.
These policy templates are referred to as port profiles.
Port profiles create a unique collaborative model, giving server administrators the autonomy to provision new
virtual machines without waiting for network reconfigurations to be implemented in the physical network
infrastructure. For network administrators, the combination of the Cisco Nexus 1000V feature set and the
capability to define a port profile using the same syntax as for existing physical Cisco switches helps ensure that
consistent policy is enforced without the burden of having to manage individual virtual switch ports.
In addition to reducing deployment time, port profiles help maintain separation of duties for the server and the
network administrators. Although virtual switches are created on Microsoft Hyper-V servers, port profiles defined
on the VSM enable the Cisco Nexus 1000V administrator to maintain and enforce consistent network policy on the
virtual access layer. In this model, the server administrator is not burdened with implementing virtual network
policy. Instead, the administrator simply applies the correct port classification to each virtual machine deployed on
the Cisco Nexus 1000V logical switch.
Microsoft Hyper-V Networking
To understand the Cisco Nexus 1000V Switch for Microsoft Hyper-V, you must first understand the basics of
Microsoft Hyper-V 2012 networking. In Microsoft Windows Server 2012, Microsoft redesigned the native virtual
switch that is shipped with Microsoft Hyper-V to implement an extensible switch. The new Microsoft Hyper-V
extensible switch architecture allows third-party vendors to provide extensions that enhance the capabilities of the
native switch supported on Microsoft Hyper-V (Figure 2). The extensions supported are:
●Filter: Provides the capability to filter certain flows
●Capture: Provides the capability to capture and redirect certain flows
●Forward: Provides the capability to filter and capture flows and perform Layer 2 forwarding
The Cisco Nexus 1000V VSM implements a forwarding extension to enhance the capabilities of the Microsoft
Hyper-V extensible switch. For more information about the Microsoft Hyper-V extensible switch, refer to the
Microsoft documentation at http://msdn.microsoft.com/en-us/library/windows/hardware/hh582268(v=vs.85).aspx.

© 2013 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 7 of 48
Figure 2. Microsoft Hyper-V Extensible Switch
Microsoft SCVMM Networking
This section introduces some Microsoft SCVMM concepts that are relevant to Cisco Nexus 1000V and its
integration with Microsoft SCVMM. For detailed information about Microsoft SCVMM networking, please refer to
the Microsoft documentation.
Switch Extension Managers
Microsoft SCVMM views third-party applications such as the Cisco Nexus 1000V VSM as configuration providers.
Before the Cisco Nexus 1000V VSM is used as a forwarding extension in a Microsoft Hyper-V switch, the VSM
must be registered with Microsoft SCVMM as a virtual switch extension manager (VSEM). After the VSM is
registered as a VSEM, Microsoft SCVMM imports all configurations defined by the VSM administrator on the Cisco
Nexus 1000V.
A VSEM is created by connecting to the VSM management IP address and the switch administrator credentials. In
Figure 3, a Cisco Nexus 1000V VSM is being added as a VSEM by connecting to the switch management IP
address of 10.10.1.10 using HTTP. A RunAs account called VSM Admin has been created using the switch
administrator credentials.

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Figure 3. Adding the Cisco Nexus 1000V as Virtual Switch Extension Manager
Note: Before the Cisco Nexus 1000V VSM is registered as a VSEM, the Cisco provider Microsoft installation
(MSI) file, which is available as part of the download bundle, must be installed on the Microsoft SCVMM server.
The provider MSI file enhances Microsoft SCVMM so that it communicates with the Cisco Nexus 1000V VSM. This
file is automatically installed on the Microsoft SCVMM server host when the installer application is used.
Logical Switch
Microsoft introduced the concept of a Logical Switch in Microsoft SCVMM 2012 SP1 to help ensure consistent
virtual network policy across Microsoft Hyper-V servers. A Logical Switch is a switch template created on Microsoft
SCVMM to help ensure that consistent virtual network policy is applied to multiple Microsoft Hyper-V hosts.
Configuration changes made to the template immediately are reflected on all the hosts on which the Logical
Switch instance has been created.
When Cisco Nexus 1000V is used with Microsoft SCVMM, a Logical Switch that uses the Cisco Nexus 1000V as a
forwarding extension is created on Microsoft SCVMM. This Logical Switch is then instantiated on all Microsoft
Hyper-V hosts on which virtual networking needs to be managed with Cisco Nexus 1000V (Figure 4). As a result of
this process, a Microsoft Hyper-V extensible switch with the Cisco Nexus 1000V as a forwarding extension is
created on Microsoft Hyper-V hosts. In addition to providing consistent network policy across multiple Microsoft
Hyper-V hosts, the Cisco Nexus 1000V implementation of a distributed virtual switch gives the administrator a
single view of the virtual network from the VSM console.

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Figure 4. Logical Switch Created on Microsoft SCVMM and Instantiated on Microsoft Hyper-V Hosts
A Logical Switch template definition contains the information shown in Figure 5.
Figure 5. Logical Switch Defines a Set of Uplink Profiles and Port Classifications
Uplink profiles and port classifications are explained in the next sections of this document.
Note: When a Cisco Nexus 1000V Logical Switch is created on Microsoft SCVMM, only one extension is used.
The Cisco Nexus 1000V is used as a forwarding extension.
Note: In this release, only one Cisco Nexus 1000V Logical Switch can be created per Microsoft Hyper-V host:
that is, creation of more than one VEM per Microsoft Hyper-V host is not supported.

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Port Classifications and Virtual Machine Networks
A virtual machine is deployed on a Logical Switch by specifying a specific port classification and a virtual machine
network configured on the Logical Switch. The port classification identifies all the network policy that must be
applied to a virtual machine‘s virtual Ethernet (vEth) interface, and the virtual machine network identifies the
network on which the virtual machine is deployed.
When the Cisco Nexus 1000V is used to manage the virtual access layer on Microsoft Hyper-V servers, the VSM
administrator creates port profiles and network segments. The Microsoft SCVMM administrator uses the port
profile created on the Cisco Nexus 1000V Switch for Microsoft Hyper-V to create a port classification. Similarly, the
administrator uses a network segment created on the VSM to create a virtual machine network on Microsoft
SCVMM.
Port Classifications
A port classification is a container or template of virtual network policy that is applied to a virtual machine’s
Ethernet interface. Microsoft SCVMM uses port classifications to define virtual network policy once and then apply
the same policy to all virtual machines interfaces requiring identical configuration. Port classifications also help
ensure that consistent network policy is applied to all virtual machine Ethernet interfaces. A change made to the
port classification is immediately applied to all interfaces on which the classification is applied.
Microsoft Hyper-V extensible switch architecture allows multiple vendors to provide extensions that enhance the
native switch’s behavior. Each of these extensions can provide network policy to Microsoft SCVMM in the form of a
port profile. A port classification combines network policy from the capture, filter, and forwarding extensions and
the native switch to define all the policy that is to be applied to a virtual machine’s Ethernet interface (Figure 6).
Figure 6. Port Classification: Collection of Port Profiles
Because the Cisco Nexus 1000V implements a forwarding extension and can perform capture and filter functions,
in practice a port classification on a Cisco Nexus 1000V Logical Switch contains only a forwarding port profile.

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In Figure 7, the Cisco Nexus 1000V administrator has defined a simple port profile called RestrictedProfile that
applies an access control list (ACL) network policy.
Figure 7. Simple Port Profile Defined on the Cisco Nexus 1000 VSM
The Microsoft SCVMM administrator uses RestrictedProfile when he creates a port classification. In Figure 8, the
administrator is creating a port classification, also called RestrictedProfile, with only one port profile: the
RestrictedProfile port profile defined on the VSM.
Figure 8. Creating a Port Classification Using the Cisco Nexus 1000V Port Profile

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Note: Port classifications are similar to port groups defined in VMware vCenter for VMware ESX environments.
However, in VMware vCenter, creation of a port profile on the Cisco Nexus 1000V results in the automatic creation
of a port group, whereas in Microsoft SCVMM, the user has to manually create a port classification. The extra step
is needed because a port classification can represent network policies from more than one provider.
Logical Network and Network Sites
The Microsoft SCVMM networking hierarchy or object model consists of the following new network constructs:
Logical Networks, Network Sites, and Virtual Machine Networks (VM Networks). Microsoft SCVMM introduced this
hierarchy to enable the consumer of network resources (server and tenant administrators) to automate the
provisioning of virtual machine networks. Also, this new networking hierarchy enables the server administrator to
request and consume network resources without needing to understand the underlying network implementation
details.
A Logical Network models distinct networks (or types of networks) managed by an enterprise. The Logical Network
abstraction hides the VLANs and IP subnets that provide isolation from all the consumer and users (virtual
machine network administrators, tenant administrators, and server administrators) other than the fabric
administrator managing the physical fabric. In other words, a Logical Network is composed of one or more network
sites, and each network site is a group of VLANS, IP subnets, or VLAN and IP subnet pairs.
Consider a hypothetical enterprise, Avatar.local, which operates two data centers: one in San Francisco and one
in New York. The enterprise has two subnets at each site:
●The San Francisco site uses subnet 10.0.0.0/8 to provide an Internal network. The subnet 20.0.0.0/8 is
used to create a DMZ network.
●The New York site uses subnet 30.0.0.0/8 to provide an Internal network. The subnet 40.0.0.0/8 is used to
create a DMZ network.
To model the network fabric of Avatar.local, the Microsoft SCVMM fabric administrator creates two Logical
Networks: Internal and DMZ. The internal Logical Network has two Network Sites: 10.0.0.0/8 and 30.0.0.0/8. The
DMZ Logical Network has two Network Sites: 20.0.0.0/8 and 40.0.0.0/8 (Figure 9).
Figure 9. Logical Network Modeling the Physical Network Fabric

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When the Cisco Nexus 1000V is used to manage the virtual access layer on Microsoft Hyper-V, Logical Networks
and Network Sites are created from the VSM. Network sites are referred to as network segment pools on the VSM
because they are a collection of VLAN and IP subnets: that is, network segments. Figure 10 shows an example of
how a Logical Network and network segment pool (Network Site) are created on Microsoft SCVMM.
Figure 10. Creating a Logical Network and Network Segment Pool on Microsoft SCVMM
Virtual Machine Networks
A Virtual Machine Network or VM Network provides isolation to virtual machines deployed on the Microsoft Hyper-
V virtual access layer.
A Virtual Machine Network of a specific type is created by the server administrator by requesting a network
resource from the Logical Network, which is a pool of Network Sites or network segments. In the example in
Figure 10, the fabric administrator has created two types of Logical Networks: DMZ and Internal. The server
administrator can now create virtual machine networks of either the DMZ or the internal type.
A virtual machine network defines a routing domain similar to Cisco virtual routing and forwarding (VRF) instances
and can contain one or more virtual subnets. Each virtual subnet defines a Layer 2 broadcast domain.
Microsoft SCVMM 2012 SP1 supports four types of Virtual Machine Network:
●VLAN
●Network virtualization using generic route encapsulation (NVGRE)
●External (VLAN)
●Not Isolation
In the first release of Cisco Nexus 1000V, only external VLAN-based isolation is supported. Other segmentation
technologies such as NVGRE and VXLAN are not supported in the first release. VLAN-backed network segments
defined on the Cisco Nexus 1000V can be used by the Microsoft SCVMM administrator to create external Virtual
Machine Networks.

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In Figure 11, the VSM administrator created a VLAN-backed network segment. The administrator is also applying
the IP pool Vlan10IPPool to the Vlan10 network segment.
Figure 11. Creating a VLAN-Backed Network Segment
When the Microsoft SCVMM administrator creates a virtual machine network, the administrator can pick one of the
available externally supplied virtual machine networks for isolation. In Figure 12, the Microsoft SCVMM
administrator is creating a virtual machine network of type DMZ. The administrator is choosing the Vlan10 network
segment defined by the VSM administrator.
Figure 12. Creating a Virtual Machine Network That Uses an External Virtual Machine Network for Isolation

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Figure 13 shows the Microsoft SCVMM network model of abstracting physical networks in terms of Logical
Networks and then allowing the tenant administrator to create virtual machine networks using the resources
available in Microsoft SCVMM Logical Networks.
Figure 13. Tenant Administrator Creating Virtual Machine Networks Using Resources Configured in Logical Networks

© 2013 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 16 of 48
IP Address Pools
Microsoft SCVMM allows administrators to create IP address pools on virtual machine networks. When a virtual
machine is deployed on a virtual machine network, an IP address from the pool is used as the static IP address on
the virtual machine. When the Cisco Nexus 1000V is used to configure the Microsoft Hyper-V virtual network, the
VSM administrator must define IP pools for a network segment. This network segment is then used by the
Microsoft SCVMM administrator to create a Virtual Machine Network.
Figure 14 shows an example of IP pool creation on the VSM.
Figure 14. Virtual Machine Network with IP Pool in Microsoft SCVMM
For more detailed information about creating virtual machine networks, please refer to the Cisco Nexus 1000V
configuration guide.
Cisco Nexus 1000V Switch Concepts and Components
This section describes the major concepts and components of the Cisco Nexus 1000V Switches and the
interaction of the components.
Cisco NX-OS Software
Cisco NX-OS is a data center-class operating system built with modularity, resiliency, and serviceability at its
foundation. Running on all Cisco data center products, Cisco NX-OS helps ensure continuous availability and sets
the standard for mission-critical data center environments. The self-healing and highly modular design of Cisco
NX-OS makes zero-impact operations a reality and enables exceptional operation flexibility. Focused on the

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requirements of the data center, Cisco NX-OS provides a robust and comprehensive feature set that can meet the
Ethernet and storage networking requirements of present and future data centers.
With a command-line interface (CLI) like that of Cisco IOS®Software, Cisco NX-OS provides state-of-the-art
implementations of relevant networking standards as well as a variety of true data center-class Cisco innovations.
Virtual Supervisor Module
The VSM provides the management and control plane functions for the Cisco Nexus 1000V Switches. Much like a
supervisor module in a Cisco Nexus 7000 Series Switch, the VSM provides the switch control and management
plane to the network administrator, coordinating configuration and functions across VEMs.
Unlike a traditional Cisco switch, in which the management plane is integrated into the hardware, on the Cisco
Nexus 1000V the VSM is deployed either as a virtual machine on a Microsoft Hyper-V server or as a virtual service
blade (VSB) on the Cisco Nexus 1010 or 1110 appliance (Figure 15).
Figure 15. VSM Representation
A high-availability deployment model of Cisco Nexus 1000V is usually recommended. Two VSMs are deployed in
an active-standby configuration, with the first VSM functioning in the primary role and the other VSM functioning in
a secondary role. If the primary VSM fails, the secondary VSM takes over.
Note that unlike in cross-bar-based modular switching platforms, the VSM is not in the data path. General data
packets are not forwarded to the VSM to be processed, but are switched by the VEM directly. Hence, any
disruption in VSM-to-VEM communication does not affect virtual machine traffic.
When the Cisco Nexus 1000V VSM is deployed on a Microsoft Hyper-V server, two installation options are
available: automated installation using the installer application, and manual installation using the VSM virtual
machine template on Microsoft SCVMM. When the VSM is deployed on the Cisco Nexus 1010 or 1110 device, the
administrator must manually install the VSM VSB. For additional information about installation, please refer to the
appropriate installation guides.
A VSM virtual machine must meet the following hardware requirements for the VSM to function correctly:
●4 GB of virtual RAM (VRAM)
●4 GB of hard disk space
●Three synthetic network adapters
When the VSM virtual machine is deployed using the installer application or the VSM virtual machine template for
Microsoft SCVMM, the requirements described in the following sections are correctly enforced.
VSM Interfaces
The VSM is a virtual machine that requires three virtual network interface cards (vNICs). Each vNIC has a specific
function, and all are fundamental to the operation of the Cisco Nexus 1000V. To define the VSM virtual machine
properties, the vNICs require the synthetic network adapter.

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The VSM can be installed using either the installer application or a manual installation process. The installer
application and the VSM template (provided for manual installation) help ensure that the VSM virtual machine is
configured with a synthetic network adapter.
Control Interface
The control interface is primarily used for VSM high-availability communication between the primary VSM and the
secondary VSM when high-availability mode is used. This interface handles low-level control packets such as
heartbeats. Because of the nature of the traffic carried over the control interface, this interface is of most
importance in Cisco Nexus 1000V Switch.
Some customers like to keep network management traffic in a network separate from the host management
network. By default, the Cisco Nexus 1000V uses the management interface on the VSM to communicate with the
VEM. However, this communication can be moved to the control interface by configuring server virtualization
switch (SVS) mode to use the control interface. Please refer to the Cisco Nexus 1000V configuration guide for
additional information about how to use the control interface for VSM-to-VEM communication.
Management Interface
The management interface appears as the mgmt0 port on a Cisco switch. As with the management interfaces of
other Cisco switches, an IP address is assigned to mgmt0. Because Layer 2 communication is not supported
between the VSM and the VEM on the Microsoft Hyper-V host as in VMware ESX, the management interface is
used for all VSM-to-VEM communication by default.
The VSM administrator can use the show interface mac address command to see the MAC addresses assigned
to control and management interfaces (Figure 16).
Figure 16. Viewing the MAC Addresses of the Control and Management Interfaces
Packet Interface
The packet interface is a traditional interface on the Cisco Nexus 1000V VSM for Microsoft Hyper-V.
Virtual Ethernet Module
The VEM provides the Cisco Nexus 1000V with network connectivity and forwarding capabilities much like a line
card in a modular switching platform. Unlike multiple line cards in a single chassis, each VEM acts as an
independent switch from a forwarding perspective.
The VEM is tightly integrated with the Microsoft Hyper-V hypervisor. The VEM is installed as a forwarding
extension to the Microsoft Hyper-V extensible switch that runs in the Microsoft Windows server kernel (Figure 17).

© 2013 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 19 of 48
Figure 17. VEM Representation
Unlike with the VSM, the VEM’s resources are unmanaged and dynamic. Although the storage footprint of the
VEM is fixed (approximately 6.4 MB of disk space), RAM use on the Microsoft Hyper-V host is variable, based on
the configuration and scale of the Cisco Nexus 1000V deployment. In a typical configuration, each VEM can be
expected to require 10 to 50 MB of RAM, with an upper limit of 150 MB for a fully scaled solution with all features
turned on and used to their design limits.
Each instance of the Cisco Nexus 1000V is typically composed of two VSMs (in a high-availability pair) and one or
more VEMs. The maximum number of VEMs supported by a VSM is 64.
VSM-to-VEM Communication
The Cisco Nexus 1000V VSM needs to communicate with the VEM to program and monitor virtual switch ports on
the Logical Switch instances (VEMs). The Cisco Nexus 1000V Switch for Microsoft Hyper-V supports only Layer 3
communication between the VSM and the VEMs. In Layer 3 mode, the control information is exchanged as Layer
3 IP packets between the VSM and VEM. Because the VSM and VEM exchange IP traffic, the VSM and VEMs can
be on different subnets as long as routing between the subnets is configured correctly. Layer 3 mode deployment
leads to greater deployment flexibility.
Note: Unlike the Cisco Nexus 1000V Switch for VMware ESX, which supported both Layer 3 and Layer 2
modes, the Cisco Nexus 1000V Switch for Microsoft Hyper-V supports only Layer 3 mode.
By default the management interface on the VSM (mgmt0 interface) is used for VSM-to-VEM communication. In
Figure 18, the dotted lines show the path taken by VSM-to-VEM communication.

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Figure 18. Management Interface on the VSM and the Microsoft Hyper-V Host Management Physical NIC Used for
Connectivity
Some administrators prefer to keep management and control traffic on separate networks on the VSM. This
separation can be achieved by using the control0 interface on the VSM to communicate with the physical
management interface on the Microsoft Hyper-V hosts. It can be configured using the following svs command:
Nexus1000V(config-svs-domain)# svs mode L3 interface[Mgmt0|Control0]
Following is an example showing how to configure the Control0 interface for communication:
Nexus1000v(config)# int control 0
Nexus1000v(config-if)# ip address 192.168.150.10 255.255.255.0
Nexus1000v(config-if)# svs-domain
Nexus1000v(config-svs-domain)# svs mode L3 interface control0
After entering this code, try to ping the 192.168.150.10 interface from the Microsoft Hyper-V hosts. You should not
be able to because a default route has not yet been set for the default VRF instance. The following CLI shows how
to set the default router
Nexus1000v(config)# vrf context default
Nexus1000v(config)# ip route 0.0.0.0/0 192.168.150.1
Figure 19 shows the control0 interface used to communicate with the VEM.