TMCnet Feature
April 10, 2013

ISPs will Need 'More Symmetrical' Links

By Gary Kim, Contributing Editor

Just how much upstream bandwidth demand might grow is a key question for all Internet service providers who support consumer customers. Though consumers continue to use much more downstream bandwidth than upstream bandwidth, the amount of upstream bandwidth obviously will grow as people start storing more content in the cloud.

Just what impact that will have on the design of networks isn’t completely clear, yet. But the ratio of downstream to upstream traffic is narrowing. In the 1990s, a 10:1 ratio of downstream to upstream traffic was a reasonable assumption.

These days, a 4:1 ratio is probably more accurate. Greater use of peer-to-peer services and social media has changed those ratios. Some might argue, not without reason, that the balance of consumer traffic will remain asymmetrical.

But it is also possible to suggest the ratios will continue to narrow. It is true that video entertainment consumption will continue to be largely asymmetrical: people will watch more video than they upload.

But uploading activity is still growing.  In May 2012, 48 hours of video were uploaded every minute on YouTube (News - Alert), and almost 70,000 hours were downloaded in the same period. Still, that means there still is a highly asymmetric 1500:1 ratio for YouTube usage.

Similarly, one might argue that the upstream requirements for online education, online health or home monitoring will add to the upstream bandwidth needs. And video communications are, by nature, fully symmetrical.

So perhaps the best way to characterize matters is that demand for upstream bandwidth will grow because downstream apps will grow so much. Even if the ratios remain constant at 3:1, if the volume of downstream bandwidth grows by an order of magnitude, then the volume of upstream bandwidth will grow by 300 percent.

ISPs will likely continue to favor asymmetrical access for some time. But eventually, gigabit symmetrical links will gain favor, as the amount of uploaded content grows. In fact, some observers would not be surprised, as that trend grows, to see more forms of local caching and distributed content delivery.

Better end-user experience, and less cost for long-haul capacity, are obvious drivers for ISPs.

Edited by Braden Becker
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