This paper investigates the channel estimation error effects on the opportunistic relay selection strategy. The opportunistic relay selection strategy is based on selecting the maximum sum-rate of half/full-duplex relay terminal among N. The investigation considers a dual-hop multiple half/full-duplex bi-directional wireless relaying networks in the system model. According to Monte-Carlo simulation results, sum-rate based relay selection strategy achieves cooperative diversity in high signal-to-noise regimes both for half/full-duplex cases. However, for the full-duplex based case, if the loop interference variances are relatively high, the achievable cooperative diversity turns out to be 0 from N while also causes system coding gain losses. The CEE causes system coding gain losses in low signal-to-noise ratio regimes. However, in high signal-to-noise ratio regimes, the CEE effects turn out to be at negligible levels.