3V0-42.20 Exam Dumps : Advanced Design VMware NSX-T Data Center

Top of Rack Physical Switches

When configuring top of rack (ToR) switches, consider the following best practices:

- Configure redundant physical switches to enhance availability.

- Configure switch ports that connect to ESXi hosts manually as trunk ports. Virtual switches

are passive devices and do not support trunking protocols, such as Dynamic Trunking

Protocol (DTP).

- Modify the Spanning Tree Protocol (STP) on any port that is connected to an ESXi NIC to

reduce the time to transition ports over to the forwarding state, for example using the Trunk

PortFast feature found in a Cisco physical switch.

- Provide DHCP or DHCP Helper capabilities on all VLANs used by TEP VMkernel ports. This

setup simplifies the configuration by using DHCP to assign IP address based on the IP subnet

in use.

- Configure jumbo frames on all switch ports, inter-switch link (ISL), and switched virtual

interfaces (SVIs).

Stateful services: Require HA mode configured as Active-Standby

Stateless services: Require HA mode configured as Active-Active

You can create different NAT rules:

• Source NAT (SNAT) translates the source IP of the outbound packets to a known public IP address so that the application can communicate with the outside world without using its private IP address. SNAT also tracks the reply.

• Destination NAT (DNAT) enables access to internal private IP addresses from the outside world by translating the destination IP address when inbound communication is initiated. DNAT also takes care of the reply. For both SNAT and DNAT, users can apply NAT rules based on the 5-tuple match criteria.

• Reflexive NAT rules are stateless access control lists (ACLs) that must be defined in both directions. These rules do not track the connection. Reflexive NAT rules are applied when stateful NAT cannot be used. For example, when a Tier-0 gateway is running in active-active equal-cost multipath (ECMP) mode, you cannot configure stateful NAT because asymmetrical paths might cause issues.

Use the Network I/O Control (NIOC) profile to allocate the network bandwidth to business-critical applications and to resolve situations where several types of traffic compete for common resources.

NIOC profile introduces a mechanism to reserve bandwidth for the system traffic based on the capacity of the physical adapters on a host. Version 3 of the Network I/O Control feature offers improved network resource reservation and allocation across the entire switch.

Network I/O Control version 3 for NSX-T Data Center supports the resource management of the system traffic related to virtual machines and to infrastructure services, such as vSphere Fault Tolerance. System traffic is strictly associated with an ESXi host.

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