Organisations and their workforces are increasingly dependent on the applications and data held within corporate systems – to do their job, employees need to remain connected. Whereas convergence brings us significant opportunity, it also increases our dependency on the corporate network with application access, information, voice communication and even video being accessible over a single LAN/WAN.
IT departments are the ones feeling the pressure on this ‘Network’ dependency. It is no longer acceptable to have network downtime, whether this be planned or not, and even a degradation in performance will result in a barrage of complaints.
The Three Aspects of Availability
Overall the resiliency of your network is decided by you. You and your business decide what level of unplanned downtime is acceptable; the closer this gets to zero, then the closer your network needs to get to five 9’s performance, i.e. 99.999% uptime.
However, it is important that in planning network resilience you consider this at each different point in your network. For example, a loss of a single access switch is likely to only impact a few dozen users, whereas the loss of a data centre switch connecting the email server is likely to have a severe company-wide impact.
Once the resilience requirement at each specific point in your network has been determined, the next step is to understand the ‘three aspects of availability’ when selecting which components and technologies to use. These aspects are as follows:
- Device Availability
- Network Availability
- Operational Availability
Products and solutions that address all of these aspects of availability are more likely to minimise downtime of the network and when failures do occur, dramatically cut the meantime to repair (MTTR).
Improving Device Availability
Step one in maximising device availability is ensuring that all high risk components such as power supplies, fan trays, control modules, interface cards and switch fabrics can be field replaceable and where possible, hot-swappable with the failover from the downed component to the backup component being automatic and seamless.
Another key step is to leverage Virtual-Chassis technology to enable the seamless failover of single chassis switches. The way this works is relatively simple, multiple switches are deployed but controlled by the network OS in a Virtual-Chassis arrangement. One switch is defined as the master and controls the Route Engine, the other switches act as the slave to the master. If for any reason the master fails, then instantly the second switch takes over as the Master with a replicated version of the Route Table ready to go.
Boosting Network Availability
Network availability encompasses those mechanisms and configurations that contribute to the availability of the network as a whole. Some of these are as follows:
Network Access Control – ensuring that your network is protected from misuse or unauthorised access. This is not only ensuring that only those designated users are permitted to join and utilise your network, it is also ensuring that they have the relevant virus and firewall protection in place to protect your network.
Path Redundancy & Resilience – to increase network uptime, redundant connections are commonly used to link access switches to the aggregation layer, to interconnect core devices, and to dual-home servers to switches in the data centre. Along with physical path redundancy, IT must consider which network protocols to rely on for fast failover or recovery in the event of a primary link failure.
Single Control Plane – IT should consider deploying a primarily routed network. While historically it made economic sense to use Layer 2 devices at the access layer, networks are less complex—and therefore more available—if a single, routed control plane operates from access layer uplinks to the aggregation and core layers. Such an architecture eliminates the need for Spanning Tree; with only Layer 3 to administer and troubleshoot, ITs’ job is simplified and human errors are reduced.
Operational Availability
Given that human error is the leading cause of network downtime, organisations have the most to gain from operational availability, which equates to simplifying routine operational management and maintenance. IT can simplify operations by selecting products with features, processes and tools that reduce complexity and automate tasks.
The secret to operational availability is reducing complexity. We strongly believe that organisations can reduce network complexity by using standards-based technologies and products. In addition, having the same software image across all layer 2 and layer 3 platforms makes it easier to roll out new features and new versions of software.
The Complete High Availability Solution
At Adtech Solutions we believe that it is possible to address all three aspects of availability while reducing both the complexity and management overhead of your network. Juniper Networks offer leading Ethernet Switching technology controlled by a single network operating system, Junos that addresses each of the elements discussed above.
If you are interested in finding out more about how you can implement Juniper network components into your existing network and improve availability, please call the Adtech team on 0118 976 3030.