Networking: Optimising the WAN
The data that flows across corporate networks is getting
richer by the day and networks are becoming more complex as time goes by. However,
connecting to remote locations is still a challenge. Be it through a VSAT link
or a terrestrial one, every entity in an organisation has to be connected to
the head office and to other locationsat least the important ones. And,
when users multiply, it isnt always possible to raise the bandwidth of
WAN links to accommodate this surge. Aishwarya Ramani finds out how companies
can and are tackling WAN bottlenecks.
companies are making hay while the sun of high investment and outsourcing shines
warmly on India. Businesses are flourishing, finances are looking healthy and
clients are mushrooming. An obvious result of this rise in business is the vast
amount of data that CIOs are required to deal with.
As data centres proliferate and companies shift to a centralised set-up, the
ecosystem consists not just of servers that process and dispatch data over the
network, but also of intermediate routers, file servers, application servers
and satellite communications.
Hence, network bottlenecks are a common occurence. Bottlenecks occur for a variety
of reasons but a common one is improper design of the network and bloating applications.
According to Akash Saraf, Joint Managing Director, Zenith
Infotech, applications should be designed properly. Designers do not pay sufficient
attention to designing and testing. This does not automatically declare the
network architecture as squeaky-clean.
K V S S S Gunneswara Rao
K V S S S Gunneswara Rao, Director, VoIP, D-Link India believes
that the network architecture and infrastructure need to be tweaked and tuned
to get the desired performance.
T G Dhandapani
CIOs dont necessarily agree with this contention. The
problem does not lie with the application nor is it the fault of the network
architecture. It is the level of knowledge that is the hurdle, feels T
G Dhandapani, Corporate CIO, Sundaram Clayton.
Hilal Issar Khan, Head, IT, Honda Siel Cars India, attributes
bottlenecks to improper network architecture.
Remote locations linked to the data centre by WANs are under pressure to support
the sheer volume of packets that need to be transported. When a packet is transported
over the network, latency comes into play contributing to bottlenecks. Latency
worsens when there are multiple technologies communicating within a network.
For instance, the latency issues of a satellite link are the highest.
We use leased lines from different vendors, Tata Net
provides us with our VSAT services, Tulip provides us the RF connection,
discloses Girish Rao, Head, IT Solutions, Marico Industries.
- Vanilla MPLS: This is a wireless last mile service
provided to users
- MPLS Network with managed services: Under this offering, customers
outsource their WAN Services to Tulip
|From 2 Kbps They also provide STM-1, STM-4 or STM-16
depending on the customer's needs
||One-time expense of Rs 75,000 to
Rs 80,000 and a recurring expense of Rs 75,000 per annum for 64 Kbps
- Secured MPLS-based VPN services which support unicasting and multicasting
|64 Kbps to STM-1
||Rs 30,000 to
|Tata Indicom VSAT Services (TIVS)
||TNET products include Corporate WAN connectivity
through TNET Star & TNET CIR products, broadband Internet through TNET
Xplore and Video streaming solutions through TNET Video
||VSAT Technology offers speeds up
to 45 Mbps downstream and up to 2 Mbps upstream
|TIVS offers broadband plans for its WAN connectivity
from Rs 1,500 per month per location for a download burst throughput of
256 Kbps (committed 16 Kbps) and upload burst throughput of 128 Kbps (committed
8 Kbps). The Internet plans start from Rs 1,900 per month for 256 Kbps speed
(capped at 250 MB)
Disparity adds complexity. I wouldnt attribute
bottlenecks to this, comments Khan of Honda Siel.
Rahul Mahajan, Head, IT, Glenmark Pharmaceuticals says, Bottleneck
issues increase when different vendors are involved. Every vendor has his own
way of designing his product. In such cases compatibility is always an issue,
and it is highly likely the products may not work together. To overcome such
situations we can deploy a mediating interface at the cost of performance.
As organisations adopt VoIP and
other convergence technologies, packets have to be treated differently
depending on their tolerance of latency. Policies dictate the priorities
that are set for different types of data
Sumit Mukhija, Business Development Manager, Cisco Systems
India & SAARC opines, Applications are generally designed to work
in a LAN environment. But there is a huge disparity between LAN and WAN speeds.
WANs cover larger distances and hence latency also becomes a critical factor
when dealing with them.
As organisations adopt VoIP and other convergence technologies,
packets have to be treated differently depending on their tolerance of latency.
Policies dictate the priorities that are set for different types of data. You
probably would set a low priority for your e-mail data, a slightly higher priority
for video and the highest priority for voice, adds Prasad Babu, Director
SE and Operations, Juniper India.
The converged network has to be fine-tuned so that each category
of data is given its fair share of bandwidth.
According to Rao of D-Link, VoIP has attained the status of
a mature technology, and positioned to play a dominant role in the converged
next-generation network architecture. Weaknesses in a data network will be magnified
when IP telephony is introduced.
Are IT satraps truly concerned about WAN bottlenecks? While IT departments do
seem content with the bandwidth of the WAN links, they feel that things may
not remain hunky-dory in the near term. We are looking to deploy solutions
like Junipers WAN Acceleration technology, comments Pradeep Kalra,
Head, IT Infrastructure, Yes Bank.
CIOs are unanimous that bottlenecks are aggravated in the
last mile. The terrestrial links that connect them to the service provider are
susceptible to bottlenecks. Deepinder Bedi, Director, Sales, Tulip India agrees
with this view. Last mile connectivity does contribute to bottlenecks.
Sometimes, unavailability of the last mile also causes bottlenecks, he
Another factor that must be taken
into account is that of a sudden increase in the number of users accessing
the network. For instance, this happens at the end of every month, when
the payroll is being processed. Most organisations go for on-demand bandwidth
when they are faced with such situations
Another factor that must be taken into account is that of
a sudden increase in the number of users accessing the network. For instance,
this happens at the end of every month, when the payroll is being processed.
Most organisations go for on-demand bandwidth when they are faced with such
Rao of Marico, however, explains the catch. There exists
a maximum cap up to which the service provider can increase the bandwidth,
Average WAN links at most organisations are in the range of
256 Kbps to 2 Mbps. While most CIOs arent bothered over much about WAN
bottlenecks they are not averse to the idea of deploying WAN optimisation technologies
in the future.
In the meantime, IT heads are making arrangements to deal with the current causes
of bottlenecks. Some common policies followed are to allocate higher bandwidth
to those areas where user concentration is higher. Marico, for example, uses
two 4 Mbps links and one 2 Mbps link for communication between the data centre
and the head office. Maricos Bandra office houses about 250 employees
and hence the high bandwidth allocation.
Service providers are doing their bit to help their customers
deal with the bottlenecks in the last mile. Tulip, for example, offers their
clients a wireless last mile. Setting up a wireless link is simple. Besides,
increasing the cap in case the customers are in need of extra bandwidth is easier
in the case of wireless, says Bedi of Tulip. He also observes that organisations
are going in for MPLS.
||Wide-Area Application Services
||WAAS is a solution for Application Acceleration and
WAN optimisation. The Cisco WAAS application acceleration technologies are
"network-transparent," in that they interoperate with the underlying
IP network infrastructure and configured features. Accelerating application
delivery to the branch requires a diverse set of optimisation techniques.
Among them are router-based, network-layer products and services and Layer
4 and Layer 7 WAAS services
||Wide-Area File Services (WAFS)
||WAFS software overcomes WAN latency and bandwidth
limitations with proprietary Cisco optimisation technologies, offering users
at branch offices a LAN-like experience when accessing the centralised files
over the WAN to lower total cost of ownership, enhance data protection,
reduce administration and ensure fast file access and sharing
||WX Application Acceleration platforms
||WX platforms improve application performance over
the WAN by eliminating redundant transmissions, accelerating TCP and application-specific
protocols, prioritising and allocating access to bandwidth, and ensuring
high availability at sites with multiple WAN links. They communicate constantly
to provide distributed stateful intelligence about the entire network, exchanging
vital information such as topology, reachability, and path-performance metrics.
The company's Molecular Sequence Reduction (MSR) technique, available on
the WX platforms, stores patterns in memory and, when it sees a repeated
pattern, sends a simple flag across the WAN rather than the full data pattern,
reducing WAN traffic by 50 to 80 percent
Rao of DLink says, Test, Test, Test; Voice is a mission-critical and time-sensitive
application and you have to look at issues in each of the OSI layers.
Mukhija of Cisco gives his checklist of dos and donts saying that one
needs to go for solutions that integrate transparently into the network and
preserve all port numbers, IP addresses and other network characteristics. He
also adds that users need to go for solutions that can provide WAN optimisation
and application-specific adapters such as CIFS (Common Internet File System)
and print services in one box.
Downward compatibility is essential. Any new infrastructure introduced
in the network for application acceleration and WAN optimisation should be compatible
with the existing infrastructure and be able to take advantage of the investments
in the routing and switching products that you have already made, says
Mukhija. He also suggests that WAN optimisation and application acceleration
solutions need to be embedded as service modules into your existing routing
and switching hardware to enable a quicker RoI.