She became the third UK woman to be killed on duty since the conflict began in 2001.
Hundreds of mourners gathered in the Co Down town on Thursday to remember Cpl Day.
Comber stood in silence in solidarity with her family as the coffin, borne by members of her regiment, 3 Medical Regiment, walked towards the war memorial.
A minute's silence was observed then the coffin was placed in a hearse drawn by two black horses and made its way through High Street, passing the house where Channing grew up with her parents Leslie and Rosemary, sisters Lauren and Laken and brother Aaron.
We should all be very proud of Channing and we will get through this all if we continue to look out for each other knowing that we have a diamond in the sky looking down on us all - our very own guardian angel
They walked hand in hand behind her hearse to First Comber Presbyterian Church where her sisters paid emotional tributes, describing her as "amazing" and speaking of their pride.
"You were the best sister I could ever have asked for," said a tearful Lauren Day.
"You were very special but, I didn't know just how amazing you were."
The congregation wept as the Army Chaplain Reverend Jackson described Channing as a "very special lady" and a "truly brave woman", and he saluted her.
He said: "Channing's passion in life from an early age was to be a soldier. That was her goal.
"She wanted to be one of the best. She wanted to be the best."
First Minister Peter Robinson flew in by helicopter from the memorial service in Enniskillen to attend the funeral.
As Cpl Day's coffin left the church it again passed her home where it paused for a few moments, amid complete silence broken only by the sound of her mother sobbing.
Cpl Day was buried at Comber Cemetery with full military honours.