The Benefits of N+1 Redundancy
A recent news story about a small town experiencing a phone outage caught my eye.
In this day and age, it’s hard to imagine what a day at work would be like if a phone outage occurred. The level of impact of an outage depends on the nature of work for the business. For example, a phone outage at a call center will result in lost orders or angry customers who are seeking support. An outage at a law firm can paralyze the firm and result in unhappy clients. Regardless of the level of impact, a phone outage is the last thing that IT administrators want.
In order to ensure uptime, redundant systems are needed to take the place of pieces of equipment in the event of a failure. For redundancy, there are two main schemes for deployment: 1+1 (often referred to as 2N) and N+1.
1+1 redundancy requires having a duplicate piece of equipment as a backup in case the primary one fails. For every piece of equipment, another duplicate piece of equipment must be available for backup. This can get quite expensive if multiple components are deployed. For example, if an IP telephony deployment has three call-control elements used to meet user demands, a redundant system would require a total of six call-control elements.
The cost of implementing 1+1 redundancy is 100% higher than the initial investment.
On the other hand, N+1 redundancy only requires one additional element to serve as a backup for an unlimited number of other elements. In the example above – of the three call-control elements – only one additional element would be required to serve as a backup for any one of the other three elements.
The cost of implementing N+1 redundancy is only 33% higher than the initial investment.
ShoreTel’s modular architecture and N+1 redundancy give businesses the flexibility to deploy an IP telephony system in whatever configuration they desire. For example, for a 200-user deployment, a business that wants to minimize costs and can’t afford redundancy can deploy a single ShoreGear 220 switch. However, if redundancy is desired, instead of buying two ShoreGear 220 switches, the business may choose to deploy four ShoreGear 50 switches, plus one additional ShoreGear 50 switch for redundancy, resulting in only a 25% increase in investment to have the safe-guard of redundancy.
For businesses that have multisite environments, this type of flexibility can be especially cost effective to ensure uptime at all locations with a minimal additional investment.