Intelligent networks are capable of high-level data routing, but
there is a reluctance by networking suppliers and their customers
to embrace the technology, writes Philip Hunter.
Intelligence is a relative concept and, applied to data networks,
it now means considerably more than it did a few years ago.
Then, it was all about making intelligent decisions about how to
route data across a network from source to destination, taking
account of variable factors such as traffic levels and availability
of particular links.
Now, the definition is starting to encompass decisions taken at the
application level, extending not just to the choice of route, but
also to the destination, the timing of delivery, and even whether
to allow the data through at all.
In other words, networks will no longer just provide intelligent
plumbing, but start making higher-level policy decisions that,
until now, have been the preserve of the end systems.
The idea is by no means universally welcomed. It seems attractive
for an internal IT infrastructure, where the network can become a
hub orchestrating the flow of data and transactions between end
systems.
It is also potentially attractive within trading chains in
business-to-business set-ups, where a trusted network can make
access and routing decisions based on policies agreed by all
parties.
Beyond jurisdiction
But where the network extends fully into the public domain, beyond
the reach and jurisdiction of internal security policies,
enterprises are understandably more nervous.
"Businesses are not going to want to have much intelligence in the
network that they do not understand or have control of," says IBM's
regional senior software consultant, Kevin Malone.
Malone says for B2B services to be effective, intelligent routing
between partners is needed at a high level. For example, if a
retail consortium makes a joint purchase of goods to exploit the
combined purchasing power of the members, there has to be a way of
breaking this transaction down and routing the relevant business
forms between the participating companies.
In fact, software exists that can perform such routing, but it is
in middleware, such as IBM's Websphere, rather than lower-level
network software. Such middleware generally resides within
enterprises and is co-ordinated by a server that acts as a hub,
orchestrating the flow of messages between systems involved in a
given transaction.
This is the most efficient, scaleable and manageable way of
implementing such high-level routing, and needs to be replicated in
some way within external networks serving multiple enterprises
within a trading community.
But, according to Malone, this is best done not by distributing
intelligence into the network, but by having a secure site acting
as a common hub, external to each of the participating companies.
That way, the network continues to provide just the plumbing,
although the hub site could be considered part of a higher-level
network.
Unsurprisingly, suppliers of routers and switches, such as Cisco
and 3Com, are not content merely to provide the plumbing, but want
to move into increasingly intelligent web-based services for both
B2B and the internet.
But middleware, unless it is integrated into standard browsers,
will not provide a suitable high-level routing medium, because it
will not be able to communicate with the client systems over the
internet.
So the remedy will have to come from standard IP-related protocols
such as HTTP. Recognising this, IBM has entered the race to develop
new versions of existing protocols that can provide the resilience
and guaranteed delivery required for future e-commerce
transactions. "We are taking some of the reliability of MQ Series
[IBM's middleware messaging software] and putting it into HTTP,"
says Malone.
Even this, however, is not taking network intelligence beyond the
level of routing and trusted delivery. The real question is whether
it will become acceptable for external networks to open up data
packets and inspect the contents of the payload in order to make
routing decisions.
It is like suggesting the Royal Mail should open letters to decide
whether the correspondent has put the right address on, or whether
the content is suitable for the stated recipient.
It is easy to see why networking suppliers, while unwilling to cede
ground to middleware suppliers such as IBM, are cautious in their
assessment of how far enterprises are prepared to go.
"At present, we are talking about the ability to distinguish
traffic based on Layer 3 and Layer 4 protocols," says Ilias
Kolovos, 3Com's product manager for Gigabit Layer 3 products.
This means ensuring that all applications, including voice and
video as well as data, can operate on an end-to-end basis with
appropriate quality of service.
Many switches and routers are now capable of distinguishing between
IP packets on the basis of information contained in their header.
But, as Kolovos says, it is still difficult to provide uniform
quality of service on an end-to-end basis across a whole network,
including the Lan, access layer and core.
3Com has been enhancing its routers and switches so they can be
configured from a central point to deliver consistent quality of
service across a whole network.
"In a traditional network, if you wanted to prioritise, for
example, Lotus Notes traffic and block gaming traffic, you would
have to manually configure ports on each switch," says Kolovos.
"Now we can apply these policies and rules network-wide."
To an extent, such facilities provide higher-level network
intelligence, since they permit routing decisions to be made on the
basis of applications rather than just prevailing network
conditions. But it is still a fairly rudimentary level of
intelligence.
Cisco is also aiming to deliver consistent quality of service. Last
month, it released its AutoQOS software, which enables quality of
service rules to be implemented without requiring much technical
expertise. This is aimed at voice over IP, which is otherwise
difficult to support consistently, and smaller enterprises, where
technical skills are scarce.
Targeting Sans
Another target for Cisco is the fast-growing storage area network
market, where the Fibre Channel protocol rather than IP/Ethernet
has, until now, provided the underlying data transmission.
Cisco believes the time is right to bring the San into the IP arena
alongside voice, to provide a common network infrastructure for all
electronic traffic.
"Storage will just be another IP application," says Bernard
Zeutzius, Cisco's regional product manager in charge of storage
networking. This will make storage networks more intelligent,
because they will be able to exploit the security, filtering and
quality of service mechanisms available for IP.
So, despite much rhetoric about intelligent networks and
application level routing, it seems that neither IP networking
suppliers nor their customers are ready for networks to start
opening packets and peering at the payload. For now, the focus is
on delivering consistent quality of service across a large IP
network - something that remains problematic, especially when it
involves routers and switches from more than one supplier.
What are intelligent networks?
- Intelligent networks decide not only how to route data across a
network, they also decide on the destination, the timing of the
delivery, and even whether to allow the data through at all
- Switches and routers are capable of distinguishing between IP
packets on the basis of information contained in headers but it is
still difficult to provide uniform quality of service
- Bringing the storage area network into the IP arena will make
storage networks more intelligent because they will be able to
exploit the security, filtering and quality of service mechanisms
already available for IP.