---
title: maximumTransmissionUnit
framework: virtualization
role: symbol
role_heading: Instance Property
path: virtualization/vzfilehandlenetworkdeviceattachment/maximumtransmissionunit
---

# maximumTransmissionUnit

An integer value that indicates the maximum transmission unit (MTU) associated with this attachment.

## Declaration

```swift
var maximumTransmissionUnit: Int { get set }
```

## Discussion

Discussion The client side of the associated datagram socket must be properly configured with the appropriate values for SO_SNDBUF, and SO_RCVBUF. Set these using the setsockopt(_:_:_:_:_:) system call. The system expects the value of SO_RCVBUF to be at least double the value of SO_SNDBUF, and for optimal performance, the recommended value of SO_RCVBUF is four times the value of SO_SNDBUF. The default MTU is 1500. The maximum MTU allowed is 65535, and the minimum MTU allowed is 1500. An invalid MTU value results in an invalid virtual machine configuration.