Analysts on Wall Street and beyond are advising caution on purchasing shares of Juniper Networks (JNPR) - Get Report . The IP router manufacturer is expected to experience several challenges ahead as its next-generation routers are likely to take a longer-than-expected time to deploy while product revenue growth stalls in a competitive internet service market.

Deutsche Bank downgraded its rating on Juniper Networksfrom "Hold" to "Sell," lowering price target from $22.50 to $21 based on estimates for fiscal 2017 and 2018.

"We are making a fundamental call versus a tactical call into earnings. Our SELL rating is based on lack of Product Revenue Growth; Services driving JNPR's Top Line, and Structural Headwinds we note for JNPR's Routers, Switches from Merchant Silicon Switch-Routers from ANET, CSCO; priced up to 50% below JNPR offerings," wrote analyst Vijay Bhagavath in a note on Wednesday.

Shares of Juniper Networks slid 2.31% to $27.75 per share in midday trading on Wednesday.

Other analysts, while positive on the company's expanding product portfolio and new CEO Rami Rahim, agree that Juniper Networks is overvalued at current levels.

"From a get go, a lot of assumptions are based on the expectations that major hyperscale and telcos are likely to deploy merchant silicon switches/routers. My view is that this deployment requires a major network re-architecting work, which is a time-consuming project," said Ilya Kundozerov, ‎senior IT and technology analyst at ‎Morningstar.

"It is certainly conceivable that these large customers are interested in the new architectures, but I believe it will take time for them to fully deploy new gear, especially for telco's such as Verizon," said Kundozerov. "As for Amazon (AMZN) - Get Report 's AWS, Microsoft (MSFT) - Get Report 's Azure, Google (GOOGL) - Get Report , Facebook (FB) - Get Report and others, as far as I know, these firms weren't big Juniper customers in the first place (Arista is a leading switch provider for these firms)."

The downgrade from Deutsche comes after Juniper was downgraded by Bernstein on Monday from "Outperform" to "Market perform." The analyst however, upped his price target to $33 per share from $30 stating he sees limited upside in 2017 

"Following cautious guidance and the resignation of the CFO, Juniper fell heavily in the first five weeks of 2016. However, the stock has rebounded ~30% since this point on the back of excellent execution and momentum in its 'cloud' business in recent quarters," wrote Pierre Ferragu, analyst at Bernstein.

Deutsche Bank analyst Bhagavath points out that although Juniper Networks seems fully valued, the company is a hyper-cyclical business. He highlights structural issues such as ASP deflation, margin erosion, and potential share loss for JNPR's custom silicon Routers and Switches from "Merchant Silicon" Switch-Routers from Arista Networks (ANET) - Get Report and Cisco Systems (CSCO) - Get Report .

Google parent Alphabet, Facebook and Cisco are holdings in Jim Cramer'sAction Alerts PLUS Charitable Trust Portfolio. Want to be alerted before Cramer buys or sells GOOGL or FB or CSCO? Learn more now.

"We recommend clients take profit" on Juniper while the company trades at about 14 times price to earnings "given our fundamental caution on weak Product Revenue Growth, consensus expectations for Top Line and Earnings Growth sponsored mainly by lower quality Services Revenues, and downward revisions we anticipate to current elevated consensus earnings estimates," wrote Bhagavath.

Dmitry Netis, analyst at William Blair & Co. partially agrees with Deutsche Bank's latest assessment of Juniper Networks, citing that the company is challenged on the routing side and believes that it should exit entirely from the even more challenged security business. 

"However, switching is ramping and they're seeing some pent-up demand current with the new core aggregation Ethernet switch QFX 10K. It's a big market and could help offset headwinds in other parts of the business," said Netis, adding that the downgrades this week make sense many are not accounting for the fact that switching could be a huge boon for the company given the markets estimated $24 billion value.

"If Juniper can gain share it could definitely give them near-term wind in their sales," he said.