When Indigo moved its premises, it seized the change to redesign
its entire network infrastructure, using the Gigabit Ethernet
technology
Indigo, part of the Telecom Eireann Group and a major provider
of Internet solutions to both business and domestic users, has just
redesigned its whole network infrastructure to take advantage of
switched Gigabit Ethernet technology. A recent move to new
headquarters in the vibrant Temple Bar area of Dublin gave Indigo
the ideal opportunity afforded by a green field site to upgrade its
existing Fast Ethernet topology.
"We were bursting at the seams in our other site, so the problems
we faced were ones of capacity as well as speed," explains Brian
Boyle, network operations manager. "The move to the new
headquarters has allowed us to completely overhaul our network
infrastructure from the wiring up, and implement a fully switched
topology with full Gigabit Ethernet backbone."Indigo's R&D
department was tasked with the job of redesigning the network,
retaining the existing Cisco Catalyst units, while ensuring that
functionality and current working practices could be maintained.
"We wanted to future proof our network infrastructure to cope with
an enormous increase in online demand," states Boyle. "Since
December 1998, traffic levels have tripled as our market share has
grown. The new infrastructure has avoided the potential bottleneck
caused by such demand."Indigo went out to the market and looked at
every major company, including Foundry, and made its decision
purely on a technical and financial basis. "Foundry gave us the
best price/performance ratio," states Boyle. "We are fortunate in
that we have a wealth of expertise in network design already in
house. Our original specifications were only changed because
features in the Foundry products allowed us to improve on our first
plan."A Gigabit fibre backbone was installed with Lucent Category
5E Gbit standard copper cable chosen for the flood wiring. Three
Foundry Networks chassis-based FastIron II switches and a FastIron
Backbone switch now sit at the very core of Indigo's operations
forming a backbone linking mail servers, news servers, access
servers, games servers and international bandwidth servers."This
cluster of switches replaces our one central switch ( a Cisco
Catalyst 5000 that has been deployed elsewhere on the network. We
no longer have a single point of failure, or are limited by the
amount of traffic the single switch could cope with," says Boyle.
"Throughput has improved tremendously and we now have built-in
redundancy. The main advantages for us, however, are the move to
full gigabit switching and the scaling up of the number of
available ports. Our total number of available ports has increased
by a factor of five, and at very little additional cost."As an ISP,
Indigo has to employ advanced security procedures in order to
control and restrict certain traffic throughout the network. "The
Foundry switches allow us to use advanced techniques like server
load balancing and transparent caching," says Boyle. "We are
particularly interested in the Foundry transparent caching
implementation. With a large customer base we simply can't manage
everybody's caching requirements at an individual level. However,
for some of our customers, transparent caching is an appropriate
methodology, and Foundry gives us the option for selective
implementation. "We also needed to implement Access Control Lists (
basically a kind of packet filtering firewall technique that allows
you to decide what has to be excluded from entering which part of
the network ( but didn't want the performance restrictions
associated with traditional routing software," explains Boyle. "The
Foundry kit performs this task at wire speed, with no drop in
performance. And, because it's hardware, it doesn't sit in the line
of the incoming data, which is what normally causes
bottlenecks."The installation and implementation was trouble-free,
and having the backbone in place proved invaluable in ensuring a
seamless move from the old premises to the new. Fibre cable was
used to link the new backbone and the old site. "The nature of our
business meant we had to stay online during the move to the new
premises," says Boyle. "Having the backbone meant that we could
move gradually and without disruption to our customers."Using a
switched topology means that Indigo could deliver 100 Mbit/s Fast
Ethernet to the desktop. "We still do the same things in the same
way, except that the traffic just whizzes about the place,"
confirms Boyle. "Expansion is no longer an issue, and we haven't
found any constraints in the switched solution, the infrastructure
should be easy to grow as we develop. The beauty is that we can now
shunt large amounts of data around and profile our traffic much
better."Profiling traffic is an important exercise for Indigo. It
allows it to monitor access levels and evaluate trends in Internet
usage. "If we understand who is trying to access what and when,
this allows us to build up a larger picture of network usage, and
then predict our growing needs, and add more resources where they
are needed, but before they become critical and impact on
performance," states Boyle. "We use a variety of home grown tools
based on SNMP to monitor and manage our network. Even with the new
topology and extra network devices, our management overheads have
not increased. All the switches have integrated management modules
that make our task much easier. Our head count is going up, but
that is only because we are a growing company. There is also a lot
of functionality and management capability in the switches that we
haven't even started to look at yet, but will be of use in the
future as traffic and demands grow further."However Boyle does
concede that network design is an art and a science stating, "Our
basic network design was based on a lot of harsh experience - it
wasn't derived from pure genius alone. We have learnt the hard way,
not with this installation, but all the guys involved brought a lot
of experience to bear, and that is probably why it went so
smoothly."
By Linda M Davies