Service Provider Mobility: Wow, not all IP
RAN transport solutions are the same!!
Posted by Dan Kurschner Aug 11, 2009
I have been supporting the emergence of IP-based radio access network (RAN) backhaul
transport for a number of years. The first IP RAN solutions were focused on 2G TDM voice
and data consisting of optimization techniques and bonding of TDM circuits to increase over-
all efficiencies. Over the past two-plus years, the focus has shifted towards 3G (with an
eye on 4G) and has moved towards leveraging Carrier Ethernet as the transport medium of
choice, taking advantage of the excellent cost-per-bit ratio over TDM circuits.
What struck me during the early days of trials, testing and initial deployments was the
consistent statements that there was no benefit of using Layer-3 routing over Layer-2
switching in RAN transport. The arguments usually centered around the logical point that
RAN backhaul is mostly point-to-point, hub-and-spoke design. Hence switching is as good
as routing, so why add complexity and expense of initial hardware purchase.
But there are benefits of implementing Layer-3 routing into the IP RAN transport network.
Perhaps the most obvious one is Direct Tunneling from the RNC to the GGSN allowing
bearer data traffic to by-pass the SGSN. Direct Tunneling allows the operator to scale to
meet ever-increasing demands on data usage while avoiding the cost of adding new SGSNs
into the network.
There are other benefits as well. Recently I have heard an increasing number of mobile
operators that are now seeing tangible benefits to deploying Layer-3 routers all the way out
to the cell site. Most of these benefits fall into the areas of what I would term as important
nuances. Features and capabilities that during the presentation and proposal process are
often discounted as not highly important. However, as mobile operators move from testing,
trials, and initial deployments to full scale deployment, they are finding that these nuances
are indeed critical to scaling their network requirements in a stable environment. Advanced
IP-intelligence, that orchestrate QoS, buffering and MPLS to provide fast-rerouting of high
priority traffic around network congestion and failures have become an important capability.
IP Security suites incorporated at all routing points are especially important when leasing
bandwidth from other network providers. These are just a few of the subtle features that had
been discounted as costly and unnecessary just months ago.
Generated by Jive SBS on 2009-12-07-07:00
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Service Provider Mobility: Wow, not all IP RAN transport solutions are the same!!
Today, as mobile operators move to full deployment and leverage shared networks, the
benefits that are part of a top-flight Layer-3 IP RAN backhaul network are becoming more
appreciated. As these same operators increase the mix of media-rich services to more end-
users, these nuances will be as appreciated in the RAN as they are today in the IP/MPLS
core networks.
297 Views Tags: mobile, mobility, mobile_internet, mobile_operators, carrier_ethernet, 3g_migration, ip_migration,
ip_ran, ran_transport, ran_backhaul
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Generated by Jive SBS on 2009-12-07-07:00
2