ADVA Optical Networking has taken a 10 percent stake in radio access network (RAN) caching specialist Saguna Networks as part of its effort to develop feature-rich offerings for mobile operators.

For a company with quarterly revenues of more than €80 million (US$102 million), the stake isn't costing ADVA much -- just $1 million. (See ADVA Reports Q3 Profit of €3.5M.)

More important is the marketing and technology support ADVA will now be able to offer Saguna, which has developed a software-based content storage and delivery package called the Content Optimization Delivery System (CODS). The aim of CODS is to enable mobile operators to store popular content at the edge of their networks using a series of interlinked caching software nodes that reside at multiple locations, including at base stations. (For more, see this brief overview.)

Saguna's technology fits neatly with ADVA's mobile backhaul offering and, once the partners have a more tightly integrated development strategy, it could give ADVA a unique selling point (USP) over the many other vendors pitching rival backhaul architectures, as the ability to store content at, and deliver content from, base stations could relieve capacity pressures on backhaul connections. (See ADVA Unveils Sync Probe for Mobile Backhaul and ADVA, Ethos Enter Ethernet Backhaul.)

There's little doubt that the use of caching and other content delivery and application acceleration technology will be vital for mobile operators as data and video traffic volumes continue to increase and pressure on their content distribution architectures grows accordingly. (See Caching In on Mobile Content.)

A recent survey of 50 mobile operators by Heavy Reading for its report, Crossing the Gi: Will Edge Caching Be the Key to Managing Mobile Traffic?, found that the majority of those operators strongly agree that video traffic management will be a serious challenge during the next three to five years.

But how should they deal with the congestion that data and video traffic can cause? Caching is certainly an option, but a tricky one for mobile carriers, according to the report's author, Senior Analyst Adi Kishore.

He says that mobile operators face a different set of technical challenges compared with their fixed line peers when it comes to deploying caching technology. According to Kishore, mobile operators are wary of breaking the GTP (GPRS Tunneling Protocol) tunnels that provide secure links between their GGSNs (packet core nodes) and base station: Deploying traditional caching systems anywhere between these two points would involve "breaking" the tunnel to cache specific content, something they are loth to do as they are "concerned about security implications and increasing complexity and cost on their networks."

Saguna's approach, though, bypasses these issues by having the caching capabilities at the end of the GTP tunnels (at the base station).

However, it also introduces other challenges. "Deploying more technology at the cell site involves more complex and therefore more expensive installs, creates new maintenance challenges and means you also need to invest in ruggedized technology [to house the caching software] at the cell site. It's not a magic bullet," says Kishore.

In addition, video traffic trends on mobile networks make it trickier to justify edge caching investments currently as the spread of content running over the networks is much more fragmented compared with fixed line network traffic. For example, says Kishore, about 33 percent of peak-time video traffic running over U.S. fixed networks is Netflix content, according to a recent report from packet inspection and policy enforcement vendor Sandvine Inc. , but Netflix streams only account for a small percentage of mobile video traffic in the same market.

That's just one of the reasons why it might be a while before ADVA can determine just how significant a USP its investment in Saguna might be. Indeed, because of the technical and operational challenges, and the scattered nature of mobile data traffic, Heavy Reading Senior Analyst Patrick Donegan, in a report on Mobile Network Feature Distribution Strategies for 3G & LTE released in late 2011, noted that distributed caching, while attracting a lot of attention from operators, is unlikely to play a substantial role in mobile networks within the next four to five years.

However, when it does, Saguna's approach might just give ADVA an edge in the market and $1 million seems like a very reasonable bet to make on a technology that could deliver much greater returns in the long run.

For more on caching and content delivery

— Ray Le Maistre, International Managing Editor, Light Reading