SWITCHES & ROUTERS |
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Most IT departments focus too much on PC and server hardware to boost network performance , however , in many cases reduced return-to-application time ( RTA ), latency sensitive applications ( VoIP , video conferencing ) can be reduced or eliminated altogether by correctly identifying the switch fabric for the installation .
Ask your customer what applications they are running now and also in , say the next two years . Are they expanding the number of users on the LAN ? Will they be providing e-commerce to the company ? Will your proposed network be able to handle the ‘ traffic ’ over the next two years and will it provide future compatibility with a minimal increase in expenditure ?
Audit the network traffic
Fundamental to any switch or router proposition is to understand what ’ s running on the current LAN . There are many third-party and sometimes free software based applications that allow the installer to visualise the traffic running across the network and any bottlenecks they may have . One important feature of LAN analysis tools is that they can identify what ’ s known as ‘ top talkers ’ on the network .
] Top talkers are network devices ( such as servers or say faulty network cards ) that constantly inject traffic onto the network with the result of crippling available bandwidth on the LAN with a result or poor performance such as increased time of retrieving accounts data from the server or slow print times to a network connected printer .
Graphing is another key feature to most of these tools . By visualising graphically ‘ real-time ’ traffic on the network and the distribution of the network protocols ( i . e . IP , IPX , NetBIOS ) the integrator can better understand what is going on around the LAN or WAN and of course get accurate values of bandwidth utilisation at any given time . Sniffing tools do a very good job of ‘ sniffing out ’ employees who rob bandwidth with applications like MSN , iChat or lunchtime gaming across the Internet , all of which have a detrimental performance on the LAN .
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From rockets to routers
Ethernet IP devices such as switches , routers and bridges ( for those who can remember that far back ) fundamentally perform the same function . They help to transmit IP traffic around between computers , diverse networks or across the Internet based on the destination IP address of the packet in question . IP , or to give it its correct terminology TCP / IP was developed in the late 1960s in the US as part of a redundantly linked military command and control system to communicate with US and NATO ICBMs facilities in the event of a pre-emptive Soviet strike to any communication link between the launch facility and command centre .
By not relying on any single point of communication ( i . e . diverse links ) commanders could be assured that communications would not be compromised by any single aggressor attack .
TCP / IP , by its nature does not need to reply on one single channel of communication . Data is broken down into smaller chunks ( i . e . packets ) which are much more efficient in transmission than larger blocks of data . It also means that diverse applications can co-exist on the same cabling with limited effect to overall performance .
It also has built-in redundancy and self-checking capabilities . TCP / IP can ‘ sense ’ congested or faulty links and with the aid of the network device in question ( i . e . a router ) make calculated judgements on sending the data onto different links instantly . Understanding the way TCP / IP operates will greatly assist any integrator to get a ‘ feel ’ for the network .
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‘ Businessclass switches have evolved greatly over the past few years .’ |
Switching to the fast lane – SME switches
Business-class switches have evolved greatly over the past few years . Offering features that make a real difference to the overall performance of the network and offer greatly improved reliability with some vendors , such as Dynamode , offering a lifetime warranty on switch solutions . SME and the enterprise have vastly different network requirements to the home user , obviously . Apart from the sheer amount of traffic that propagates the network , other issues need to be accounted for . Overall network speed such as Gigabit Ethernet , advanced monitoring and security functions and of course hardware redundancy in one package .
Layer 2 switches as they are sometimes called effectively are more often than not Rackmount 24-Port or 48-Port high density 1U switches that offer reasonable performance with some advanced features worth considering .
To help maintain higher levels of IP data throughput vendors have adopted features such as ‘ cut through ’ which allows wire-speed data transmission with minimal packet checking . Depending on network load and model types , these L2 Switches may re-configure themselves to ‘ store and forward ’ which means the data is thoroughly checked ( i . e . its checksum ) before being sent to the destination device .
A compromise used by some L2 Switches is ‘ adaptive switching ’ meaning the switch senses if the data needs to be checked , based on network utilisation and application type . PoE ( Power over Ethernet ) is the new kid on the block now and is certainly worth considering should you be deploying PoE devices such as
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June 2017 | 33 |