The Network mode can be used with any infrastructure configuration.
However, when an alternative transport mode is applicable, the Network mode is not recommended because of the lowest data retrieval speed. It is the only applicable mode when the backup proxy is a physical machine and the host uses local storage. In this mode data is retrieved via the ESX(i) host over the LAN using NBD (Network Block Device) protocol.
The process of data retrieval in Network mode includes the following steps:
1.The backup proxy sends a request to the ESX(i) host to locate the necessary VM on the datastore.
2-4 The host locates the VM, copies blocks of data and sends them to the backup proxy over the LAN.
5.The backup proxy sends the data to target.
The Network mode is not recommended if you have 1Gb Ethernet because of traffic throughput via the LAN, as the copy of the VM disk usually contains a lot of data. However, this mode can work well if you have 10Gb Ethernet (performance will be good enough).
If VM disks are located on different storages (that is, on the SAN and local storage subsystem), Veeam Backup & Replication will use different transport modes to process them. In such scenario, it is recommended that you enable the Failover to network mode if primary transport modes fail or are unavailable option when configuring the mode settings for the necessary backup proxy.