CSE 588 - Spring 2002 - Transcription

University of Washington Department of Computer Science & Engineering

CSE Home

Our main goal is to design an Internet, which is a network of
Heterogeneous Networks.

For this we will need to decide what the host will do, and what the
router will do, and actually what each of the connected Networks can do?




The Characteristics of a Network to be connected to the Internet vary
greatly:

*	They deliver Data
*	Can vary in Bandwidth from 1Kb/sec to 10 Gb/Sec which is 7
orders of Magnitude
*	The Loss Rate can vary greatly too, like between wired and
wireless networks
*	The network can be Simplex or Duplex
*	Bus Architecture or Switch Architecture
*	Circuit switched like the telephone system or Packet Switch like
the current Internet
*	Packets can also be

	*	 Corrupted
	*	Of Limited Size
	*	Reordered
	*	Duplicated
	*	Or lost

*	They also may have differing capabilities:

	*	Real Time
	*	Multicast
	*	Guaranteed delivery

*	Different Addressing Mechanisms







Functionality

Corrupt Packet Detection:

*	This can be done by the hosts.  If the networks are unreliable
you may need some kind of detection to be done by the Routers too.
*	If you have End to End checks you may still need the networks to
check for the following reasons

	*	Debuggability for quickly detecting network problems
	*	Speed.  To reject the packet early on it's path and not
waste resources taking it all the way there.
	*	Routing Info is part of the packet and may be corrupted

*	Why should the hosts check if the networks do:

	*	They may not trust all the networks on it's path
	*	Routers can corrupt the data
	*	Can provide stronger error checking




Retransmission:

Done by Hosts, Networks if needed




Ordering of Packets:

Done by hosts




Routing:

Usually done by the Routers, can be done by the hose in the case of
Source Routing where you put on the packet the path you want it to
follow.




Congestion Control:

Network/Internet




Flow Control:

Hosts




The different entities that take part in the internet are as follows:

Networks

Routers

Hosts

Transport

Application

Border Routers

Name Servers

Middle Boxes i.e. Load Balancers

Department of Computer Science & Engineering
University of Washington
Box 352350
Seattle, WA 98195-2350
(206) 543-1695 voice, (206) 543-2969 FAX
[comments to owner-cse588]