Barclays' Ben Reitzes suggests his downgrades of EMC and NetApp are partly valuation calls (both companies are near his PTs for them). But he adds "there may be more upside in networking names today" in light of "long-term headwinds to storage demand." The growth of cloud infrastructure platforms relying on commodity hardware (AWS being the most notable) is generally viewed as a threat to storage incumbents.
EMC and NetApp are pure storage companies and have little to do with Silicom. Silicom provides the plumbing components and are tightly aligned with the networking companies. Storing it fast is what EMC and NetApp are good at and getting it between point A and point B fast and secure is what the networking companies are concerned with.