When it comes to network performance, there’s no single metric by which to judge network health. Douglas Smith, president of network analysis vendor Network Instruments, points out that it’s a mistake to think that network utilization can be quantified in a single way. When management asks for a single network utilization report, IT is typically sent scurrying for a single metric for network health that is ultimately impossible to define.
That said, certain aspects of a network, such as port utilization, link utilization, and client utilization, can and should be measured. In any scenario, successful network analysis means taking a step back and looking at the data in the context of your enterprise.
Network utilization requires judgment calls. If two ports on a switch are 90 percent utilized and the others are not utilized, do you consider your switch utilization to be 90 percent? It might be more appropriate to ask which application is causing those particular ports to reach 90 percent utilization. Understanding the big picture and analyzing utilization levels in context are the keys to getting a sense of your network’s health.
13. Throwing bandwidth at a network problem
One of the most common complaints addressed by IT is simple: The network is running slower than normal. The knee-jerk reaction is to add more capacity. This is the right solution in some cases but dead wrong in others. Without the proper analysis, upgrading capacity can be a costly, unwise decision. Network Instruments’ Smith likens this approach to saying, “I’m running low on closet space, and therefore I need a new house.”
Capacity aside, common root causes of slowdowns include unwanted traffic broadcasting over the network from old systems or apps, such as IPX traffic, or misconfigured or inefficient applications that spew streams of packets onto the network at inconvenient times.
According to Smith, one of Network Instruments’ banking customers was considering upgrading its WAN links due to complaints from tellers that systems were running slow. The IT team used a network analyzer to determine that increased traffic levels were being caused by a security app that ran a daily update at 3 p.m. When the IT team reconfigured this application to make updates at 3 a.m. instead, they were able to quickly improve traffic levels without making the costly WAN upgrade.
14. Permitting weak passwords
In the Internet age, new threats such as worms and phishing tend to garner all the security attention, but the SANS Institute’s Top 20 Vulnerabilities list released in October points to a basic IT mistake: weak authentication or bad passwords (infoworld.com/2193). The most common password vulnerabilities include weak or nonexistent passwords; user accounts with widely known or physically displayed passwords (think Post-it Notes); administrative accounts with weak or widely known passwords; and weak or well-known password-hashing algorithms that are not well secured or are visible to anyone. Avoiding the weak authentication mistake boils down to simple IT blocking and tackling -- a clear, detailed, and consistently enforced password policy that proactively deals with the most exploited authentication weaknesses detailed in the SANS report.
15. Never sweating the small stuff