JPMorgan analyst Rod Hall notes that Bloomberg yesterday indicated renewed speculation about a potential combination of Cisco (CSCO) and Ericsson (ERIC). The analyst does not believe a Cisco combination with Ericsson makes sense "from a strategic and/or technological perspective." Further, his analysis suggests that earnings accretion likely would be limited to only 10%. Ericsson would likely have a negative impact on Cisco's margins, which would lead to multiple compression, Hall tells investors in a research note. He keeps a Neutral rating on Cisco shares.