Verizon may have been claiming to be the America's largest LTE network and have the most reliable nationwide coverage, but the carrier's assertions are falling short to user's expectations.

Verizon Wireless, one of the leading network carriers in the U.S., claims to have the largest LTE network nationwide. The rapid growth, however, may not be working well in its favor. According to Verizon's financial officer Fran Shammo, the huge customer base was hampering quality service delivery.

"There are certain pockets where we're absolutely going to experience that down tick from the LTE network down to 3G because of capacity constraints," Shammo said during an investor conference, according to CNET.

 Shammo's acceptance places a big question on the company's claims of having the most reliable network across the United States. Verizon is the longest running LTE provider with highest number of users benefitting from its high-speed service in the U.S. It is evident that customers expect a lot more from the most-experienced service provider.

While customers are being pushed back to the older 3G network in certain cities, this affects the data speed massively as the LTE network offers speed ten times faster than 3G.

As Verizon faces issues managing the rapid growth and increasing data traffic, the company is certainly making vigorous efforts to keep up with the challenges and continue to dominate the LTE market in the U.S. Verizon is investing an additional $500 million in the company's capital expenditure. In addition, it is also working toward giving a reliable network to its users by investing in small cell technology.

"By the end of this year you are going to see all those issues dissipate," Shammo added. "And then going into next year we will be ahead of the curve again."

Verizon has its 4G LTE service available in more than 500 U.S. markets.  AT&T is the biggest challenger to Verizon's LTE network. AT&T is growing significantly at a faster rate with its LTE service in more than 370 U.S. markets. The carrier is working toward covering 420 U.S. cities with nearly 270 million people using its service by the end of this year.