Network Delivery Mechanisms - A Practical Guide to Video and Audio Compression - page 343

Table 19-3 Useful Networking Utilities

Utility Description

Useful for determining whether you can reach a target node and
examining the quality of the service in terms of latency. This will also
tell you if you are barred from reaching the target device. This tool and
others may be compromised when trying to use them to penetrate a
firewall or proxy service.

ping

A tool for examining routing complexity between your client and a
target server. Certain “hops” may take lengthy times to resolve and this
will help you to diagnose a “stale” route, that is, one that was
previously established and has somehow become locked in but is no
longer valid. This tends to happen with dialup connections and can be
resolved by your ISP.

traceroute

One of the tools for determining the domain name for an IP address .

whois

A useful tool for decoding a DNS domain name into an IP address and
vice versa.

nslookup

Tells you what connections your machine has made since it was last
booted.

netstat

A tool for examining traffic between your machine and another. You
can determine ports and message status over the connection.

tcpdump

A widely available utility that sets your Ethernet interface to a special
mode (promiscuous) where it will be able to examine traffic on your
sub-net regardless of whether it is to and from your client node or not.
Switched hubs may prevent this from being very useful but having a
machine equipped to share a network via a hub will help diagnose
very hard-to-find problems. You can also observe traffic and build
bandwidth-monitoring, error-detection, and logging tools with this
approach.

snoop

more about this by contacting BBC Technology (now part of Siemens Business Services)
and asking about Colledia.
Architecting a system such as this is quite challenging. In the BBC News 24 studio,
there may be thousands of hours of video retained online at any one time. Several hun-
dred journalists are working on this content at once so the architecture of the shared-file
system is very important. Large server engines with storage area networks and proxy
copies of the video for desktop browsing enable this system to be built and deployed
with current technology although quite a lot of specialized coding has taken place to join
it all up.

BBC Ventures Group: http://www.bbcventuresgroup.com/
Siemens Business Services UK: http://www.sbs.siemens.co.uk/