1. Network Analyzer Example
Internet
User clicks on
Ethereal network analyzer captures all frames observed by its Ethernet NIC
Sequence of frames and contents of frame can be examined in detail down to individual bytes
Ethereal web site,
(This material is for self study.))

2. Ethereal Protocol Analyzer
A network protocol analyzer is a tool for capturing, displaying, and analyzing the PDUs that are exchanged in a network. Current analyzers cover a very broad range of protocols and are constantly being updated. Protocol analyzers are also extremely useful in teaching the operation of protocols by providing a means of examining traffic from a live network.
Communication Networks uses the Ethereal open source package, which supports an extensive set of protocols, including: PPP, HDLC, Ethernet, MPLS, IP, IPv6, ARP, ICMP, RIP, OSPF, UDP, TCP, DNS, HTTP, telnet, FTP, RSVP, RTP, SIP, H.323, SSL and TLS, PING, and traceroute.
Ethereal can be run in two modes. In the first mode, the Ethereal application opens existing packet capture files for analysis. In the second mode the Ethereal application captures a frame sequence in real time and then stores the result in a packet capture file. In this document we provide a number of packet capture files that can be used by the instructor to demonstrate and analyze protocols in class. In a separate document we provide lab experiments for capturing these frame sequences.
The Ethereal package can be downloaded from Their web site also contains instructions and example screen captures.

3. Ethereal windows Middle Pane shows encapsulation for a given frame
Top Pane shows frame/packet sequence
Bottom Pane shows hex & text

4. Top pane: frame sequence
TCP Connection Setup
DNS Query
HTTP Request & Response

5. Middle pane: Encapsulation
Ethernet Frame
Ethernet Destination and Source Addresses
Protocol Type

6. Middle pane: Encapsulation
And a lot of other stuff!
IP Packet
IP Source and Destination Addresses
Protocol Type

7. Middle pane: Encapsulation
TCP Segment
Source and Destination Port Numbers
GET
HTTP Request