* QoS grows more palatable
Quality of service has been a prominent topic for years, as the need to gain service-level control over connectionless IP networks has grown increasingly intense. And there are piles of sophisticated QoS technologies and features out there that, when configured just right, can prove extremely useful to enterprises wishing to ensure that certain application traffic always gets the network resources it requires to perform well.
However, many IT departments have traditionally found the complexity and time associated with QoS provisioning to be a big deterrent to managing – rather than simply adding – bandwidth. At its most basic, a successful QoS deployment typically involves the following steps:
1. Figuring out which applications need some level of QoS.
2. Establishing a corporate traffic-treatment policy based on the above.
3. Determining which QoS features on which devices should be configured to support the policy.
4. Enabling the features with the appropriate parameters.
The features referenced in No. 4 include (but are not limited to):
* Classifying traffic.
* Marking traffic with the appropriate priority.
* Setting up the desired number of priority queues in switches and routers.
* Rate-limiting certain traffic so it doesn’t hog capacity.
* Traffic shaping to smooth out peaks and bursts that can cause temporary congestion.
* Configuring jitter buffers if voice is involved.
* Identifying packets for temporary random discard when congestion flares up.
Whew!
Router vendors, including Alcatel and Cisco, have figured out that enterprises do not have copious amounts of spare time to delve this deeply into detail. So they have begun to automate the QoS configuration process. They are doing so with templates built based on their years of experience with enterprise networks, the network requirements of the most-used enterprise applications and their own best practices.
Enabling network QoS is particularly relevant to traffic as it is forwarded from the enterprise WAN edge router across the last-mile link to the service provider network. This is the network segment where the least amount of bandwidth is usually available and, as a result, where congestion is most apt to occur.
And if you are running voice over IP – as is increasingly the case – you do have to figure out how to make sure VoIP always makes it to the “real-time” queue in your switches and routers, both locally and on the WAN.
Next time: Under the covers of automated QoS.
