In the prior installment of this series, we discussed the potential cost and logistics of the Equipment Room as part of improving cellular signal indoors. This post covers the final link in the chain to the mobile core, the backhaul. FYI, if you
are new to this series and want to get the most out of it, please start here, and read the posts in sequence.
Setting the Stage
According to one of our Tier-1 operators, Backhaul is the number two largest item behind Labor in their Opex budget. It is a cost that is actively managed and any creative approaches to reducing it, while not risking the Quality of Experience of their subscribers, matters.
With that thinking in mind, let’s dive in.
The traditional approach to networking indoor cellular systems to the mobile core, be it legacy technology (like an eNodeB or Picocell) or Enterprise Radio Access Network “E-RAN” use leased private network facilities.
Private Networks can be:
- Dark fiber (mucho cost)
- Metro Ethernet (urban cores)
- Private IP-VPN (wider availability, MPLS technology)
A common characteristic of these transport networks is that they are highly deterministic and can be tightly controlled to insure optimal performance on the data path. As you probably know, LTE is very much an “end-to-end” architecture where IP packets from each traffic flow (e.g. common data, signaling, VoLTE) possess different priority markers. When a network is congested, these markers enable transport networks to prioritize time bounded flows, like VoLTE, over best effort flows, like common data.
You said “Free Backhaul.” How?
Well, it’s not free, but almost, because it’s using a service that is already in place. In the spirit of completely re-thinking existing approaches to delivering cellular, we suggest using a game changer like Internet for E-RAN backhaul.
In situations where the enterprise Internet link has excess capacity available and can serve as the path to the mobile core from the E-RAN, Internet is viable. This is very much the case in large enterprises and universities where 10Gbps Internet ports are commonly deployed and the actual consumption is less than the available port capacity. This excess capacity can now be used to carry traffic from LTE devices, at no additional cost to the enterprise or the operator.
Believe it or not, Internet based backhaul can actually be better than more expensive private IP backhaul. Why? Most subscribers judge the quality of LTE services based on the speeds they get. If an operator connects an E-RAN system to a 100 Mbps private circuit, then the maximum data rate that a subscriber will ever experience will be 100 Mbps. However, if an operator uses the enterprise’s 500 Mbps Internet Connection, then suddenly the peak rate that a subscriber experiences could go as high as 300 Mbps (on a dual-LTE system with Carrier Aggregation)
The other benefit of Internet is time-to-market. Operators invest a sizable chunk of money in building an indoor cellular system. Using enterprise Internet allows them to turn on these systems sooner and start getting a return on their investment – whether through acquiring new subscribers or offloading the macro network. And if, after three months, they are not happy with the enterprise Internet backhaul, they can always bring their own private IP backhaul.
Note that the operator is not compromising security by using Internet because of end-to-end encryption… from Services Node to the Security Gateway on the border of the core network.
And, of course, with Internet there is minor risk to the indoor subscribers due to occasional Internet last mile congestion. But, for most situations, a big enough last mile link will not congest to a point where lack of QoS controls would create visible problems.
It is also useful to consider that Internet connection sharing will have little net impact on the last mile (the link from Enterprise site to nearest supporting Internet POP). For enterprises that are off-loading their Wi-Fi network by moving mobiles to LTE, the Internet last mile usage remains unchanged because it’s the same traffic to/from Internet.
Finally, when future buying paths are considered, converging all IP traffic onto Internet path can improve the business case whether it’s for the mobile operator or enterprise IT.
Two examples to illustrate this:
- Operator is providing E-RAN as a managed service. Shared IP connection to core network over Internet can eliminate private network Op-Ex costs and greatly improve the business case for investment.
- Enterprise is buying E-RAN. Shared IP connection to core network over Internet eliminates private IP Op-Ex. If Internet upgrade is required, buyer gets far more Mbps/$ when buying Internet.
To recap, E-RAN is “enterprise IT friendly” by using:
- Any available type of IP transport to the mobile core.
- Seamless upgrade capability if operator or enterprise desires move from Internet to private IP.
In the next installment, we will summarize the end-to-end benefits of E-RAN to satisfy the voracious needs of today’s mobile employees in the enterprise.
– Art King, SpiderCloud Wireless, Director of Enterprise Services & Technologies
Visit our Enterprise IT site @ http://SpiderCloud.com/EInsider
Other posts from the Enterprise Deployment Series:
- Enterprise Deployment – Setting the Stage
- Enterprise Deployment – Ethernet and the Physical Layer
- Enterprise Deployment – Telecommunications Room
- Enterprise Deployment – Telecommunications Room Interconnection
- Enterprise Deployment – Equipment Room
- Enterprise Deployment – Backhaul
- Enterprise Deployment – Summary