Joebedford writes
“I've been updating automatically via wireless for many years at home but I turn updates OFF when travelling.”
Simply put, “Wireless” WiFi radio connections continually monitor the signal strength of the connection.. If signal drops too far the radio card can and will AUTOMATICALLY negotiate the connection speed
DOWN until it reaches an acceptable speed for the signal strength.
Therefore WiFi connections are HIGHLY DYNAMIC, the speed changes are supposed to be “seamless” but in the real world WiFi connections can and do get interrupted.
Interruptions of the Wifi connection while surfing the internet or viewing email are typically harmless and often not noticeable other than perhaps a delay in web pages updating..
BUT when dealing with MISSION CRITICAL FILES like as with your OS updates, changes in the connection speed, lost connections or RFI (interference) of that connection can and will corrupt the downloading files..
READ HERE ABOUT WIFI AUTONEGOTIATIONText from above link..
“Question: Why Do Wi-Fi Connection Speeds Keep Changing?
Wi-Fi networks support certain maximum connection speeds (data rates) depending on their configuration. However, the maximum speed of a Wi-Fi connection can automatically change over time.
Answer: This behavior is called dynamic rate scaling, a design feature of Wi-Fi networks. When a device initially connects to a network via Wi-Fi, its rated
speed is calculated according to the current signal quality of the connection. The rated connection speed then automatically changes over time if necessary to maintain a reliable link between the devices. Wi-Fi dynamic rate scaling extends the range at which wireless devices can connect to each other in return for lower network performance at the longer distances.
802.11b/g/n Dynamic Rate Scaling
An 802.11g Wi-Fi device in close proximity to a network router will often connect at 54 Mbps. This maximum data rate is displayed the device's wireless configuration screens. Other 802.11g devices located further away from the router, or with obstructions in between, may connect at lower rates. As these devices move further away from the router, their rated connection speeds eventually get reduced by the scaling algorithm, while devices that move closer can have speed ratings increased (up to the maximum of 54 Mbps.
Wi-Fi devices have their rates scaled in pre-defined increments. For 802.11g, the
defined ratings are (from highest to lowest)
54 Mbps
48 Mbps
36 Mbps
24 Mbps
18 Mbps
12 Mbps
9 Mbps
6 Mbps
Similarly, old 802.11b devices supported the following ratings
11 Mbps
5.5 Mbps
2 Mbps
1 Mbps
Controlling Dynamic Rate Scaling
Factors that determine which data rate is dynamically chosen for a Wi-Fi device at any given time are:
distance between the device and other Wi-Fi communication endpoints
radio interference in the path of the Wi-Fi device
physical obstructions in the path of the Wi-Fi device, that also interfere with signal quality
the power of the device's Wi-Fi radio transmitter/receiver
Wi-Fi home network equipment always utilizes rate scaling; a home network administrator cannot disable this feature.”Distance from the router/AP, radio interference (RFI), walls/objects can cause your WiFi to shift speeds..
Distance and RFI are the two main causes of speed changes..
To be very clear, most WiFi connections DEFAULT to the 2.4ghz frequency band.. That band is “shared” by MANY other devices like MICROWAVE OVENS, portable cordless land line phones, BLUETOOTH DEVICES and many more.. Not to mention OTHER peoples own Wifi APs which may also be on the same "channel" as yours..Wired network connections pretty much are immune to RFI and will stay a constant speed which was negotiated when the PC was booted onto the wired network..
Not to mention that a wired 100 Mbps network connection IS considerably FASTER than a 54Mbps WiFi connection and if you have 1Gbps network connection (Aka Gigabit) it is lightning fast when compared to WiFi. The faster the update files get transferred to your PC the LESS chance of corruption!
Granted there are 108Mbps WiFi connections but more often than not that connection will be substantially slower than 108Mbps and not to mention unless you have the newest latest greatest 108Mbps radio card AND router/AP on both ends you will only get 54Mbps or the top speed of the lowest device (108Mbps radio card connecting to a 54Mbps router/AP will give you a max of 54Mbps).
Just because you have WiFi “available” it doesn’t mean it is the "best" to use all the time..
I prefer to default to a WIRED connection as much as possible for best results (IE speed AND reliability).