[Def.] Backlogged packets

Q. What's the Backlogged packets?

A: 

it's a packet stuck in a buffer, unsent to the recipient because of network congestion. You probably don't see the word much in computer networking because it is used in cellular phone networks. In voice networks, where delivery is time sensitive but dropped packets can be tolerated, a backlogged packet is usually dropped.

네트워크분야에서는, 네트워크의 혼잡으로 (CSMA/CA에서 예를들면, 채널이 busy하거나, 패킷간 충돌이 발생했을때) 인하여 전송하려고 하던 패킷을 버퍼에 넣어두고 기다릴 때 전송지연되는 패킷을 말한다.

ex)

In slotted Aloha, If a transmission has a collision, the node become backlogged.