ENABLING AFFORDABLE BANDWIDTH IN THE SATELLITE MARKET
Why
Enterprise Caching should be deployed on all satellite links
(courtesy of Expand Networks)
Executive Summary
Satellites, with their ubiquitous coverage,
can bring the data connectivity to every corner of the globe, with no
terrestrial infrastructure. However, Satellite bandwidth will always be
expensive due to the limited supply and the lack of disruptive technologies
that reduce cost by several orders of magnitude unlike DWDM in terrestrial
optical lines. Hence, a technology that enables enterprises and satellite
providers to “squeeze” more bandwidth out of their existing
infrastructure is required.
Expand’s ACCELERATORs, through the
use of Enterprise Caching technology, have consistently shown at least 100%
improvement in network capacity on Internet links. This equates to a 512 Kbit
satellite link being equivalent, if not better, to a 1024 Kbit link. The extra
bandwidth translates to significant cost savings and improved performance that
can make satellite links more cost-effective for both enterprises and service
providers.
Introduction
Fuelled by the demand for Internet access around the world, the use of Satellite for Internet backbone links has been consistently growing over the last decade.
Growth in ISP Satcoms Link Usage
Source: DTT Consulting, 2001
Satellite Internet backbone
connections typically originate either in the US or Europe, where important
peering points and Internet exchanges are located. However, most of these
connections are used to reach countries and or geographical areas that are not
are not covered by terrestrial infrastructure (e.g. developing
countries in
Latin America, oil rigs in the North Sea, transport and navy ships), or where
terrestrial connections are either unavailable, or are extremely expensive.
The following chart shows the geographical breakdown of remote
sites.
ISP Satellite Remote Locations, by Region in MBit/s
Source: DTT Consulting 2001.
Growth and cost
Though underserved, these
bandwidth-challenged regions will experience significant demand-side growth in
the next years as IP traffic is expected to grow exponentially. Since
terrestrial alternatives will take long to appear in these markets, these
networks will be challenged with congestion, flexibility, reliability, and
scalability.
In addition, bandwidth costs to these countries are
extremely high due to the lack of supply, making bandwidth a critical component
of any enterprise or service provider that operates a Wide Area or Global
Network to these markets. This fact makes reducing cost of bandwidth an
important advantage when addressing some of these resource-limited
markets.
The satellite challenges
Satellite present a few challenges to enterprises using them for backbone connectivity or for satellite service providers selling such connectivity. The two most important challenges in deploying satellite-based connectivity are:
Bandwidth prices are much higher than terrestrial alternatives;
Latency is an unavoidable consequence, leading to inferior TCP throughput.
Enterprise Caching reduces Bandwidth Cost
Based on existing deployed technology the required price points for some countries which could be prime candidates for satellite IP are extremely hard to meet. More than any other network configuration, a satellite IP network needs to be optimized as bandwidth costs will continue to be a key component in its viability in the different markets.
Implications for satellite Internet service providers
During 1997-1998, several
Satellite Service Providers provided European ISPs with satellite capacity to
connect to the US backbone. However, the proliferation of cost-effective
terrestrial capacity caused most ISPs to cut down on their use of satellite
links. Today, there are almost no ISPs in Western Europe utilizing satellite
for backbone access.
The Europe example highlights the importance of
maintaining competitive pricing in rapidly changing market conditions. As
terrestrial alternatives appear and/or become more affordable, Satellite
Service providers may find themselves under pressure to reduce prices.
Enterprise Caching can come to the rescue. By providing extra capacity on
existing network infrastructure, Satellite Service providers can grow their
revenue streams and reduce costs:
Add users to their existing infrastructure, utilizing the extra capacity gained through enterprise caching.
Postpone the need for technology updates to the satellite infrastructure to accommodate growth and higher bandwidth needs.
Pass on some of the cost savings to their end-users and remain price competitive with terrestrial technologies.
Implications for enterprises using satellite links
Satellite links are often cost-prohibitive since they provide the only possible connectivity to underserved regions. Enterprises can benefit immediately from Enterprise Caching deployments, as it provides 100-400% and often more improvements in available bandwidth. The extra capacity is dependendent in the traffic mix flowing through the link. This extra capacity provides an excellent cost avoidance mechanism for links that need to be upgraded, and can also be used as a cost reduction strategy for existing links.
Latency implications for Service Providers
It is common knowledge that the
TCP protocol is vulnerable to high latency that is inherent to satellite links,
leading to poor throughput.
However, numerous studies have shown that
this is only noticeable when attempting to achieve individual TCP sessions of
over 400 Kbit/sec each.
Not surprisingly, latency has not
been a serious issue for ISP backbone links. Most ISPs who use satellite as
backbone offer dial-up connectivity to their users. Since the modem’s
speed is limited to under 56Kbit/sec, the end users do not feel TCP’s
limitations.
Moreover, in order to utilize their most expensive
resource, ISPs try to load their backbone connection with as many users as
possible. This causes the satellite “pipe” to be filled with
thousands of simultaneous, individual TCP sessions – each of which is
allocated only a few Kilobits. Enterprise Caching helps this effect. Because
Enterprise Caching reduces bandwidth consumption of individual TCP sessions,
more sessions can be fit in the satellite pipe, and the average session
bandwidth will be even lower.
Specifically, Service Providers will be
able to accommodate for a significantly higher number of users on a given
“pipe”.
Objective results - ISP
The following MRTG graph generated by an ISP using the Cisco router clearly illustrates the ACCELERATOR’s effectiveness on a T1 (1.544 Mbps) 2-way satellite link.
The graph contains real-life
ISP traffic (combination of HTTP/FTP/POP3/etc.). The blue line represents WAN
bandwidth (sent over the satellite link), optimized by the
ACCELERATORs.
The shaded green area represents the effective bandwidth transferred over the
link and delivered to the LAN (user) side. It is clear that the ACCELERATORs
enabled a dramatic 50% decrease in traffic over the satellite link.
Flexible Network Implementations
The ACCELERATOR product line has multiple deployment scenarios. For satellite links, the ACCELERATORs can be connected to:
A satellite modem via serial interface
An Ethernet LAN (between router and LAN or as a Server on the LAN)
A FRAD (CSU/DSU) for Frame Relay
Since satellite networks are mostly point-to-point systems, ACCELERATORs should be connected to the satellite modems in service providers and corporate networks. LAN connectivity may be the preferred connectivity when the corporation relies on a managed service, or there is an encryption or VPN device before the modem.
Summary
Expand’s field-proven
Enterprise Caching can come to the rescue of satellite links at a time when
they are experiencing price and capacity pressures.
By providing 100%
and often more extra capacity on existing network infrastructure, Satellite
Service providers can grow their revenue streams and reduce costs. For
enterprises ACCELERATORs provide an excellent cost avoidance mechanism for
links that need to be upgraded, and can be used as a cost reduction strategy
for existing links.
About Expand
Networks
Expand Networks pioneered the development of Enterprise
Caching Technology which increases network speed, capacity and throughput by
100 to 400 percent or more. Expand Networks offers a reliable, cost-effective
and easy-to-deploy solution to the strain created on networks by
mission-critical applications such as Intranet, Extranet, B2B, ERP, CRM, Thin
Client and the Web. By accelerating the deployment of new services and
applications and offering sophisticated monitoring and management capabilities,
Expand Networks improves the end-user experience and reduces the Total Cost of
Ownership. Clients include leading organizations such as Motorola, Texas
Instruments and the United States Department of Defense. Expand Networks is
headquartered in Roseland, New Jersey and Tel Aviv, Israel with offices
throughout the United States and in the United Kingdom, France and Italy. The
company's sales force is augmented by a global network of Value Added
Resellers. To learn more, visit www.expand.com or call (888) 892-1250.
