What is a Virtual Standard Switch (vSS) in ESXi

Introduction

Networking is one of the most critical components of any virtualized environment. In VMware ESXi, virtual machines (VMs) rely on virtual switches to communicate with each other and the external network. One of the most fundamental networking constructs in ESXi is the Virtual Standard Switch (vSS).

In this guide, you’ll learn what a Virtual Standard Switch (vSS) is, how it works, its architecture, features, limitations, common use cases, and how it compares to the vSphere Distributed Switch (vDS).

Whether you’re new to VMware or preparing for VMware certifications, understanding vSS is essential.

What is a Virtual Standard Switch (vSS) in ESXi?

A Virtual Standard Switch (vSS) is a software-based Layer 2 network switch that operates inside a single ESXi host. It provides network connectivity for:

• Virtual machines (VMs)
• VMkernel services (vMotion, Management, iSCSI, NFS, etc.)

Unlike physical switches, a vSS does not exist as hardware. It is created and managed directly on each ESXi host.

Core Components of a vSS

1. Virtual Switch (vSwitch)

The main switching entity that forwards traffic between ports.

2. Port Groups

Port groups define:

• VLAN IDs
• Security policies
• Traffic shaping rules

Examples:

• VM Network
• Management Network
• vMotion Network

3. Uplinks (Physical NICs)

Physical adapters (vmnic0, vmnic1) provide external network connectivity.

4. VMkernel Ports

Used for ESXi host services like:

• Management
• vMotion
• vSAN
• iSCSI / NFS

Key Features of Virtual Standard Switch

✅ Host-Level Networking

Each ESXi host manages its own vSS independently.

✅ VLAN Tagging

Supports IEEE 802.1Q VLANs for network segmentation.

✅ NIC Teaming & Failover

Provides redundancy and load balancing across multiple physical NICs.

✅ Security Policies

Configurable settings for:

• Promiscuous Mode
• MAC Address Changes
• Forged Transmits

✅ Traffic Shaping

Control inbound and outbound bandwidth usage.

Advantages of Using vSS

✔ Simple to configure
✔ Ideal for standalone ESXi hosts
✔ No vCenter Server required
✔ Lightweight and reliable
✔ Perfect for labs, SMBs, and edge deployments

Limitations of Virtual Standard Switch

While vSS is reliable, it has notable limitations:

Limitation	Explanation
Host-level only	Cannot span multiple ESXi hosts
Manual configuration	Must be configured individually per host
No centralized management	Requires direct ESXi access
Limited advanced features	No NetFlow, LACP, or Port Mirroring

vSS vs vSphere Distributed Switch (vDS)

The Virtual Standard Switch (vSS) and vSphere Distributed Switch (vDS) differ mainly in scope and management. A vSS operates at the individual ESXi host level and is configured separately on each host, making it ideal for standalone or small environments without vCenter Server. In contrast, a vDS is managed centrally through vCenter Server and spans multiple ESXi hosts, providing consistent network configuration across the entire cluster. While vSS offers basic networking features such as VLANs, NIC teaming, and security policies, vDS includes advanced capabilities like centralized management, Network I/O Control, NetFlow, LACP, port mirroring, and enhanced monitoring, making it the preferred choice for enterprise-scale VMware environments.

Feature	vSS	vDS
Management Scope	Single ESXi Host	Multiple Hosts
Requires vCenter	❌ No	✅ Yes
Centralized Config	❌ No	✅ Yes
Network I/O Control	❌ No	✅ Yes
Scalability	Low	High
Enterprise Features	Limited	Advanced

How to Create a Virtual Standard Switch (High-Level)

1. Log in to ESXi Host Client
2. Navigate to Networking > Virtual switches
3. Click Add standard virtual switch
4. Assign physical NICs
5. Create port groups
6. Configure VLANs and policies

Security Best Practices for vSS

• Disable Promiscuous Mode unless required
• Restrict MAC address changes
• Separate management traffic
• Use dedicated VLANs
• Monitor NIC failover settings

Performance Considerations

• Use multiple uplinks for redundancy
• Align VLAN configuration with physical switches
• Avoid oversubscription
• Enable jumbo frames if required (iSCSI/NFS)

Final Thoughts

The Virtual Standard Switch (vSS) is the foundation of VMware ESXi networking. While it lacks advanced enterprise features, its simplicity, reliability, and independence make it a vital component of many VMware environments.

Understanding vSS is essential for:

• VMware administrators
• Virtualization engineers
• DevOps professionals
• Certification candidates (VCP)

Frequently Asked Questions (FAQ)