ImagiNation Network

interface for the ImagiNation Network shows the colorful art treatment meant to appeal to children.
The ImagiNation Network, originally known as The Sierra Network, was the first online gaming network.

Games

ClubHouse

Checkers

Chess

FlipFlop (previously called Reversi)

Backgammon

Bridge

Hearts

Spades

Euchre

Cribbage

LarryLand

(a.k.a. CasinoLand)

Poker

Black Jack

Craps

Roulette

Veracity

MedievaLand

The Shadow of Yserbius

The Fates of Twinion

The Ruins of Cawdor

SierraLand

NTN Trivia

Minigolf

3D Golf

Paint Ball

Boogers
an Ataxx clone

3D Tic Tac Toe

Red Baron (later moved into the Arena Land)

Graffiti
collaborative art drawing board

Rocket Quiz (later moved into the school house)
Stratego
the classic board game
FunHouse

( AKA School House)
RocketQuiz
a 1 to 3 player math quiz game
Arena
Red Baron
Front Page Sports: Football
History
1991: ImagiNation Network launches
1994: AT&T buys ImagiNation Network
October 6, 1996: AOL buys ImagiNation Network
1996: AOL cancelled ImagiNation Network
Emoticons

INN had emoticons programmed into its system. The user just needed to type Alt+#, and it would give a corresponding face.

Protocol

The protocol was a simple stop-and-wait protocol with explicit acknowledgment of packets. Packets had a start marker, a sequence number, a 16-bit CRC, the data, and a stop marker. If the start or stop marker occurred within the data, it had to be escaped. All good packets received in the proper order were acknowledged. Any packet out of sequence cause a NAK for the missing packets that came before it. Any packet with a bad CRC also got a NAK. If a NAK was received, or an ACK did not occur within a reasonable amount of time, the packet was retransmitted.

They later moved to a sliding window version of the same protocol to cut down on the number of ACKs that were sent. This didn't change the packet format, but it did cut back on retransmissions.