The document discusses transfer reliability and congestion control strategies in opportunistic networks. It begins by stating that opportunistic networks have unpredictable node contacts and rarely have complete end-to-end paths. It notes that modified TCP protocols are ineffective for these networks. The document then surveys proposals for ensuring reliable data transfer and avoiding network congestion in opportunistic networks. It categorizes existing proposals and identifies mechanisms like hop-by-hop custody transfer and end-to-end receipts for reliability. For congestion control, it discusses replication management, drop policies, and considering message copy numbers. The document concludes by identifying open research challenges.