UDP

[jonk34567]

UDP can transmit data at a rate higher than the path capacity. is this statement true ?

[ghostinthenet]

No. No protocol will allow you to exceed the capacity of the data path. However, UDP can allow for more efficient use of the path than TCP does. UDP, unlike TCP, has no generic built-in session maintenance and window management mechanism. This allows the application to define its own mechanisms that may be more efficient. Good examples of this would be QUIC or DTLS.

[Joseph W. Doherty · Accepted solution]

Answer depends on how you define "data" and "path capacity".

Every path has some physical bandwidth capacity, and that cannot be directly exceeded.

However, an application using UDP, or other protocols, might be using some form of data compression. If so, the data transmission rate might be more than the nominal physical path capacity.

If there's no form of compression, the data transmission rate, as Jody notes, will not exceed the physical path capacity. Further, protocols, including UDP, introduce overhead, so you generally are unable to obtain a data transfer rate, again without some form of compression, that even obtains the physical path capacity. (In fact, for some data, the effective transmission rate is but a small percentage of the utilized physical capacity. For example, send one 8 bit character via a UDP packet.)

[Thomas Roeckel]

This is an ICND Question and i think the answer is: YES

See RFC5405:

On many platforms, applications can send UDP datagrams at the line rate of the link 
interface, which isoften much greater than the available path capacity, and doing so
contributes to congestion along the path.

[Joseph W. Doherty]

Yes, an interface can send faster then the downstream path's capacity. Whether a UDP application does that depends on the application.

Likewise, TCP applications may do the same until TCP detects packets drops, or with some later TCP implementations, detects a jump in RTT, then the TCP protocol, not the application, will slow its overall transmission rate, although it will ramp up its transmission speed until again it detects drops and/or (with some TCPs) an increase in RTT latency.