Hi Guys,

I attended the IP09 show a couple of weeks ago and a frequent statement / question made by IT management was “ we are already running qos on our routers isn’t this similar to bandwidth management? ”
In the UK British Telekom markets Qos enabled networks which further clouds the reality as consumer feel they have already ticked that box.

Most people I chatted to however admitted that they still have poor VoIP/SAP/CRM/Video quality at times and were really interested in the differences once we got talking.

Of course when you start adding acceleration , proxies (such as web cache, DNS, FTP etc) , compression etc into the mix then there are many differences – but let’s take a step back and look at the basics - Qos (or queuing) vs. actual management of the protocols.
Using Queuing Schemes on Routers
Routers' queuing schemes--such as, weighted fair queuing, priority output queuing, and custom queuing-- attempt to prioritize and distribute bandwidth to individual data flows. Queuing schemes try to prevent low-volume applications, such as interactive web applications, from getting overtaken by large data transfers, typical of FTP traffic.

Router-based queuing schemes have several limitations:

• Routers manage bandwidth passively, tossing packets and providing no direct feedback to end systems. To try to control traffic sources, routers use queuing--that is, buffering--which adds delay and results in dropped packets.
• Router queuing is uni-directional--it affects only traffic going from the LAN to the WAN.
• Queuing results in chunkier traffic and erratic performance because multiple, independent TCP sources are competing for bandwidth--ramping up and backing off--which causes queues to accumulate at the access link. Queuing, especially weighted fair queuing, doesn't work well for chunky flows because packets arriving in chunks tend to be discarded.
• Routers don't allow you to set guaranteed rates for specific traffic types.
• Rate specification in routers is imprecise. You can't specify high-speed and low-speed connections separately and you can't specify speed in bits-per-second.
• Traffic classification is too coarse. For example, router can't classify traffic by URL, treating all flows the same at the web site.

Opteq provides several key functions that differentiate it from other bandwidth-management solutions:

Opteq provides the technology (host pacing) that enables you to explicitly control TCP and UDP bandwidth to keep your network under your control.
Opteq manages traffic just before the link is congested and ensures that high priority traffic never gets caught in a queue of buffer shuffle -(kicks in with the threshold value )
High priority traffic essentially has a free lane through the network as if the network was empty. No more jitter, latency, buffers, queues, drops retransmissions etc

This technology offers the following bandwidth-management features:
• Classifies traffic for precise control. Opteq can even classify by a specific application or URL.
• Controls the end-to-end connection, so users experience smooth, even data displays.
• Allocates bandwidth according to your rules or policies.
• Explicit bits-per-second rate control, giving you the ability to specify guaranteed rates and to define how total bandwidth should be allocated
• Smoothed traffic flow--that is, evenly paced transmissions--eliminating the burstiness associated with web traffic and ensuring consistent quality of service
• Precise traffic classification with a variety of criteria.
• Bi-directional traffic control, unlike routers, which control outbound traffic only.
• Direct feedback to the sender about transmission rate and flow status, rather than the indirect feedback provided by routers.

Add to this further optimisation and security technologies and you have a predictable and secure high speed WAN>