Welcome to our SGML and XML Resource site


TCP Window Size – Quick Primer

The TCP window size is basically the method employed by the receiving client/host to inform the sender, what the current buffer size should be for all the data within that connection.  It’s a flow control system which ensure that the receiving host doesn’t get overloaded with data, it’s very important that this is a dynamic…

Read More

Some IP Routing Stuff

Conceptually IP routing is pretty straight forward, especially when you look at it from the hosts point of view.  If the destination is directly connected such as a direct link or on the same Ethernet network then the IP datagram is simply forwarded to it’s destination.  If it’s not connected then the host simply send…

Read More

The TCP Keepalive Timer

If you’re new to the world of TCP/IP, you may be quite confused to hear that no data at all flows across an idle TCP connection.  Just to clarify, if no process on either side of the connection is sending data then nothing at all will be exchanged by the 2 TCP modules.  Many networking…

Read More

The Basics of the Domain Name System

So what is the Domain Name System or as it’s more commonly known as DNS? Well, very simply it is a huge distributed database which contains the domain names and addresses of all devices on the network.  This structure is crucial to the way DNS functions, it allows local control of specific segments – and…

Read More

TCP/IP Congestion Avoidance Algorithm

Lost packets is one of the biggest difficulties for any transport protocol.  Sending data across a variety of platforms, switches, hubs and routers is bound to end up with some lost data.  Every protocol therefore needs a way of dealing with these lost packets.   The congestion avoidance algorithm is one way of dealing with…

Read More

Defining an Internet Address

Absolutely every device that exists on the internet needs an IP address (some call it an internet address). There are no exceptions – every pc, laptop, phone, coffee machine or printer if it’s online and accessible it needs an IP address. Needless to say the internet facing ones have to be unique in order to…

Read More

A Little Bit About IP Checksums

The role of checksums in IP headers is actually very important.  THey are used to make sure that data is not corrupted during it’s journey from the source address to the destination.  TCP/IP uses a specific algorithm to check the data which involves dividing the checksum data in separate 16 bit fields.  Every one of…

Read More

  • Recent Posts