Networking Standard Switch

Short definition:-

vSphere Standard Switch: A software-based switch that resides in the VMkernel and provides traffic management for VMs. Users must manage vSwitches independently on each ESXi host.

vSphere Distributed Switch:- A software-based switch that resides in the VMkernel and provides traffic management for VMs and ESXi hosts across the entire cluster. Distributed vSwitches are shared by and managed across entire clusters of ESXi hosts.

Port Groups:- A vSwitch allows several different types of communication. Port groups differentiate between the types of traffic passing through a vSwitch. It also operates as a boundary for communication types and security policy configuration.

VMkernel port group and VM port group:- A vSwitch allows several different types of communication, including communication to and from the VMkernel and between VMs.

VMkernel port group:- Communication to and from the VMkernel is supported by VMkernel port group.

VM port group:- Communication between VMs are supported by VM port group.

VMkernel Port:- A specialized virtual switch port type that is configured with an IP address to allow VMkernel traffic. VMkernel port allows vMotion, iSCSI storage access, network attached storage (NAS) or Network File System (NFS) access, or vSphere Fault Tolerance (FT) logging. In vSphere 5 environment a VMkernel port also provides management connectivity for managing the ESXi hosts.

Service Console Port:- VMware ESX use traditional Linux-based Service Console port for management traffic.

Spanning Tree Protocol (STP):- In physical switches, Spanning Tree Protocol (STP) offers redundancy for paths and prevents loops in the network topology by locking redundant paths in a standby state. Only when a path is no longer available, STP will activate the standby path.

Uplinks:- vSwitches must be connected to the ESXi host’s physical NICs as uplinks in order to communicate with the rest of the network.

Management network:- In order for the ESXi host to be reachable across the network, a VMkernel port is configured automatically....... this is called management network.

VGT (Virtual Guest Tagging) or VLan id 4095:-Normally the VLAN ID will range from 1 to 4094. In the ESXi environment, VLAN ID 4095 is valid...... Using this VLAN ID with ESXi causes the VLAN tagging information to be passed through the vSwitch all the way up to the guest OSs that support and understands VLAN tags.

VMkarnel Port:- VMkernel ports provide network access for the VMkernel’s TCP/IP stack. VMkernel networking carries not only management traffic, but also all other forms of traffic originating from the ESXi hosts like vMotion, iSCSI, NAS/NFS access, and vSphere FT logging.

NIC teaming:- The aggregation of physical network interface cards (NICs) to form a single logical communication channel. Different types of NIC teams provide varying levels of traffic load balancing and fault tolerance.

NIC teaming in vSphare:- The aggregation of physical network interface cards (NICs) to form a single logical communication channel. NIC teaming in ESXi hosts involves connecting multiple physical network adapters or uplinks to a single vSwitch. Different types of NIC teams provide varying levels of traffic load balancing and fault tolerance.

***** REMEMBAR:- NIC team Load Balancing is Outbound and connection oriented:-

1.The load-balancing feature of NIC teams on a vSwitch applies only to the outbound traffic.

2.The load-balancing feature of NIC teams on a vSwitch do not equalize data flow through all available adapters, instead it balances number of source to destination connections within team members.

vmxnet Adapter :-A virtualized network adapter operating inside a guest operating system (guest OS). The vmxnet adapter is a high-performance, 1 Gbps virtual network adapter that operates only if the VMware Tools have been installed. The vmxnet adapter is sometimes referred to as a paravirtualized driver. The vmxnet adapter is identified as Flexible in the VM properties.

Traffic Shaping:- if Uplinks or physical network cards bandwidth contention becomes a bottleneck hindering VM performance, then it is possible to enable and to configure traffic shaping for bandwidth control.

Traffic shaping involves the establishment of hard-coded limits for peak bandwidth, average bandwidth, and burst size to reduce a VM’s outbound bandwidth capability.

NIC Teaming Load balancing Policies:-

ð vSwitch port-based load balancing

ð Source MAC-based load balancing:-

ð IP hash-based load balancing:-

ð Explicit failover order:-

vSwitch port-based load balancing (default):-This policy assigns each virtual switch port to a specific uplink. Failover to another uplink occurs when one of the physical network adapters experiences failure.

Source MAC-based load balancing:-This policy works as the name suggests, ties a virtual network adapter to a physical network adapter based on the MAC address. Failover to another uplink occurs when one of the physical network adapters experiences failure.

IP hash-based load balancing:-This policy uses the source and destination IP addresses to calculate a hash. The hash determines the physical network adapter to use for communication. Different combinations of source and destination IP addresses will, quite naturally, produce different hashes. Based on the hash, then, this algorithm could allow a single VM to communicate over different physical network adapters when communicating with different destinations, assuming that the calculated hashes lead to the selection of a different physical NIC.

Explicit failover order:-The last option, explicit failover order, isn’t really a “load-balancing” policy; instead, it uses the user-specific failover order.

NIC teaming Failover detection method:-

ð The link status failover detection method

ð Beacon-Probing Failover detection method

The link status failover detection method:- Failure of an uplink is identified by the link status provided by the physical network adapter.

The downside to the link status failover-detection setting is its inability to identify miss configurations or pulled cables.

Beacon-Probing Failover detection method:- ESXi/ESX periodically broadcasts beacon packets from all uplinks in a team. The physical switch is expected to forward all packets to other ports on the same broadcast domain. Therefore, a team member is expected to see beacon packets from other team members. If an uplink fails to receive three consecutive beacon packets, it is marked as bad. The failure can be due to the immediate link or a downstream link.