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The Hammer PacketSphere Network Emulator « carlos-m.net

The Hammer PacketSphere Network Emulator

This was written for English class with Chantel Acevedo while I was in 12th grade at Winchester Thurston School. Its purpose was to imitate the entries in The Hitchhiker’s Guide to the Galaxy from the novel of the same name by Douglas Adams.

Carlos Macasaet
May 8, 2001
English 12 — Galactic Guide Entry

Hammer PacketSphere Network Emulator (an Empirix product)

Hammer PacketSphere&tm; Network Emulator

The Hammer PacketSphere is a cool looking device that when placed in one’s living room will cause visitors to marvel at the impressive looking piece of hardware. The visitors will then proceed to ask the owner of the device what exactly the machine does and they will be amazed at both said person’s technological knowledge and ownership of such a cool device.

Aside from carrying great aesthetic appeal, the Hammer PacketSphere serves as an interesting instrument used for modeling real world situations on computer networks.� It is a well-known fact that packet-switched networks such as those that this device works with, do not always function as intended.� However, in the development stage of such networks, the computers are in a very controlled environment.� Thus, the chances of errors occurring on the network are very slim.� As a result, unforeseen network problems often occur when networks are deployed.�


To avert such network problems, Empirix has developed this LAN packet-degrading device to generate what they refer to as “IP network impairments”.� As the Hammer PacketSphere is designed for LANs, it works only for Ethernet connections.� However, it is highly scalable and will work with either one full-duplex Gigabit Ethernet connection or eight full-duplex 100Base-T connections.� Once installed on a network, the Hammer PacketSphere can be used to simulate network problems that could occur when the network experiences heavy usage.


Having acquired a Hammer PacketSphere, a network administrator would place the device between two Ethernet ports on the network.� This may pose some difficulty for the network administrator, as instead of needing just one full-duplex category 5 twisted pair cable connecting the two ports, the administrator will be required to obtain two.� In addition, installation of the Hammer PacketSphere will cause a temporary disruption of service between the two ports.� But this will not last long as long as the network administrator has the necessary cabling prepared.�

Now, the Hammer PacketSphere is a bit odd in that it has two power switches.� However, once the network administrator overcomes this obstacle, he will be ready to configure the device.� The Hammer PacketSphere comes with configuration software for Microsoft Windows 95/NT/2000.� Empirix does not support any other operating systems.� At first this may seem like an inconvenience for garage based Internet startups running Linux, FreeBSD and the like, however, it seems appropriate that the Hammer PacketSphere be Windows based as its primary purpose is to cause problems.

The network administrator will then need to include the Hammer PacketSphere’s default IP address to the network.� This completed, configuration of the Hammer PacketSphere is done through a web browser on another computer.� This allows the network administrator to provide a list of IP addresses for whose traffic the contraption will cause problems.� The Hammer PacketSphere will then mess with the packets passing through it and originating or destined for the IP addresses specified; all others will pass through unscathed.�

The Hammer PacketSphere is programmed to perform five very destructive functions.� It simulates packet loss by dropping either every nth packet or dropping packets based on percentages.� It causes latency (lag) by creating either a constant packet delivery delay, a gaussian distribution or a uniform distribution from a range of minimum and maximum delay.� In addition, it can simulate gradual increases and decreases in packet transfer rate.� It causes packet duplication, by which it emulates “stupid” network devices that resend packets when not necessary.� It reorders every nth packet or percentage of packets.� Finally, it simulates packet rerouting by delaying packets for a certain time period over a larger recurring period.

In conclusion, the Hammer PacketSphere, while not used to hammer by any definition of the verb nor spherical in shape can do some very nasty things to IP packets.� This makes it ideal for testing in LAN lab and enterprise situations.� It can also test the effectiveness of LAN and other network applications, in particular, voice over IP (VoIP), in which network performance is crucial.� It also allows for worst-case scenario modeling.� In addition, it is ideal for those looking for a large object to take up space in their server rack or those looking for a conversation piece that would evoke a certain tech-saviness in the owner.

More information regarding the Hammer PacketSphere is available at the manufacturer’s website at: http://www.empirix.com/empirix/voice+network+test/products/packetsphere.html.

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