The End-to-End Argument is important to analyze and understand the proper
method for deployment specific network functionality.
The basic idea is that a proposed function should only be considered and
implemented into the network itself when that function can be implemented in the
network with such a completeness that all users of the network would benefit
from its implementation. If there is any type and level of cost to implementing
said function inside the network, even when most of the clients or traffic in
the network does in fact use it, this cost of implementing may not make sense.
An alternative to implementing a function inside the network is for the end
clients to implement the function. Examples of this are encryption, flow control
and guaranteed delivery of data; the End to End argument had a significant
impact on the design of the TCP protocol to guarantee reliable transmission over
unreliable networks. The End to End argument has been a reliable form of
governance to keep the network simple and to deliver solid performance for all
One area in particular where the End to End argument has not entirely been
upheld relates to network monitoring and management. Most network management
and monitoring systems focus on individual components of the network such as
routers and switches. It is entirely possible that each one of these component
work correctly, but the clients on the network are losing packets or
experiencing performance issues. The only way to see these problems is to
monitor the end-to-end function of packet delivery and performance from the
endpoints of the network. Monitoring from the end clients provides the ability
to see the performance of the network as the End User is actually experiencing
the network. This allows the monitoring system to find the effects of problems
anywhere in the network path – – from user to the application.
Areas where these problems exist and which are often difficult to monitor
- End station operating system, TCP stack and network hardware.
- LAN Network, performance, packet loss, latency and other uses.
- First Hop Router issues and router access control
- Outbound controls such as Web URL Filtering, or Proxies.
In a recent problem we were involved with at a Virtyx client where a small set
of End Users reported they were having problems accessing the Internet. This
report came in via phone and quickly receded into background noise. This report
was escalated to the network team, each silo (LAN, WAN, Firewall and Internet)
went into their tool of choice, and to no great surprise not one silo team
reported a problem.
The report from the End User did not have a definitive timestamp of when the
problem commenced or when it subsequently cleared so it was difficult to
correlate the problem with any other monitoring tools. If the End User
workstations had end point monitoring installed on them we would have been able
to see the when, where, what and why of the problem(s) that End User
experienced. It would also allow the collection of additional information which
the End User could not collect or convey as part of the problem report. At this
point we don’t know exactly what happened or what caused the issue and it will
be something which can be held over the network team until we determine the root
of the problem.