1. ip addressing example work sheet User PC A ip 165.140.20.03 msk 255.255.255.128 g/w 165.140.20.56 Network User PC B ip 165.140.20.04 msk 255.255.255.128 g/w 165.140.20.56 User PC C ip 165.140.20.100 msk 255.255.255.128 g/w 165.140.20.56 User PC G ip 165.140.8.1 msk 255.255.252.0 g/w 165.140.11.254 Network User PC H ip 165.140.8.3 msk 255.255.252.0 g/w 165.140.11.254 User PC K ip 165.140.10.1 msk 255.255.252.0 g/w 165.140.11.254 Printer ip 165.140.8.3 msk 255.255.252.0 g/w 165.140.11.254 ROUTER (GateWay) TO other networks, Internet etc. KCC Feb 1998 NOTE mask = 255.255.255.128 (25 bit network) ie upto 126 local connections NOTE mask = 255.255.252.0 (22 bit network) ie 1022 local connections 165.140.20.56/25 165.140.11.254/22 PC X ip msk g/w PC Z ip msk g/w COMPLETE THE CONFIGS FOR PC X, Z

2. Ethernet Reminder the original single segment network. all devices share the same cable or collision domain. Remember Ethernet CSMA/CD = Carrier Sense,Multiple Access, Collision Detection….. only one device can use the cable at one time. P C with the use of layer2 bridges segments could be connected together. each work group has its own collision domain. traffic is kept local using the mac address. Unfortunately, broadcast traffic is sent to all segments (all users in same broadcast domain). only one device in each segment can use the cable at one time. BRIDGE P C ROUTER with the use of a layer 3 router the three segments become separate networks with their own collision domain and broadcast domain. The router can makes decisions based upon protocol, company policy, traffic levels etc… only one device in each segment can use the cable at one time. KCC Feb 1998

3. Ethernet Reminder 2 P C P C 1P C 2P C 3 P C 7P C 8P C 9 ROUTER KCC Feb 1998 H U B P C the hub or repeater (layer 1) extends the physical specification and enables use of cabling over a greater distance. all devices still are in same collision domain and same broadcast domain. only one device can use the the above network at one time. S W I T C H P C the use of a simple ethernet switch provides an ethernet bridge for each port. each switched port is a separate collision domain. the switch is a layer 2 device hence all ports are in the same broadcast domain. S W I T C H P C 4P C 5P C 6 S W I T C H use of more complex configurations can provide VLANs (virtual local area networks) where PC 1,2,3,7 & 8 are in one vlan and PC 4,5,6 & 9 are in another. each vlan is a separate broadcast domain and each switch port can provide a separate collision domain. interswitch link to/from other routers and switches in the company network

4. FRAME CONSTRUCTION EXAMPLE KCC August 1999 FTP DATAFTP HEADER TCP DATATCP HEADER IP DATAIP HEADER DATAFRAME HEADER DATA SIGNALPreamble FRAME PACKET SEGMENT Example TCP PORT # 21 = FTP content Example PROTOCOL #6 = TCP content Example DIX frame TYPE #0800 = IP content Example FTP session LAYER 4 LAYER 3 LAYER 2 LAYER 1 LAYER 5

5. TCP SEGMENT CONSTRUCTION destination port 0 4 8 16 19 24 31 checksum options (variable length)padding d a t a urgent pointer windowoffsetreserved UAPRSF source port sequence number acknowledgement number FLAGS; U Urgent A Acknowledgement P Push R Reset S Synchronize SYN F FIN TCP = IP protocol # 6 UDP SEGMENT CONSTRUCTION destination port 0 4 8 16 19 24 31 source port d a t a UDP checksumlength UDP = IP protocol # 17 KCC August 1999 LAYER 4

6. IP PACKET CONSTRUCTION KCC August 1999 DATAFRAME HEADER FRAME identification total packet length 0 4 8 16 19 24 31 versionhdr lengthTOS flagsfragment offset destination address options (variable length)padding d a t a TTLprotocol #header checksums source address LAYER 3 LAYER 2

7. ETHERNET FRAME CONSTRUCTION KCC August 1999 DATATYPE/LENGTHFCSsource mac addressdestination mac addresspreamble/SD 64 to 1518 Bytes long 41 to 1500 Bytes long 6628 802.2 SSAP/DSAP 4 (+5) 4 L E N G T H I N B Y T E S NOTE… Ethernet DIX frame preamble is 8 bytes long with no SD byte, Ethernet DIX frame has TYPE field and no LENGTH or 802.2 fields. Ethernet IEEE 802.3 frames have 7 byte preamble, 1 byte SD, Ethernet IEEE 802.3 frames have LENGTH field and no TYPE field, Ethernet IEEE 802.3 frames have 802.2 field for 2 byte DSAP, 2 byte SSAP, 2 control bytes and 5 byte SNAP (if used DSAP and SSAP = 0xAA). Therefore the largest Ethernet frame size should be 1518 bytes and the minimum frame size should be 64 bytes in order to stay within the Ethernet specification and be able to detect a collision. The frame size was extended to 1522 bytes by a IEEE 802.3 committee workgroup (802.3ac) to support VLAN tagging using 802.1Q but several manufactures equipment still will not support giant frames (larger than 1518). Frame sizes have been pushed even further with the latest technologies. ISL (Inter Switch Link) VLAN tagging extends the frame by an additional 30 Bytes, MPLS (Multi Protocol Label Switching) adds 4 Bytes for each label….. etc. etc. so it is not unusual to see giant frames on today’s networks. LAYER 2

8. UTP & AUI Ethernet Cabling RJ-45 SOCKET VIEW 1 2 3 4 5 6 7 8 pin assignment; pin # MDI-X function MDI function 1 Rx + Tx + 2 Rx - Tx - 3 Tx + Rx + 6 Tx - Rx - NOTE; most Ethernet equipment has MDI-X ports (Media Dependant Interface Crossover) and some supply an MDI or switchable MDI/MDI-X to enable connection of to 10BaseT devices without the use of a crossover cable. Some equipment uses the 15 pin D AUI connection ; pin # function 1 ground 2 CI-A 3 DO-A 4 ground 5 DI-A 6 VDC ground 9 CI-B 10 DO-B 11 ground 12 DI-B 13 VDC +12 14 ground 15 ground KCC Feb 1998 NOTES; NOTE: Chiron makes use of RJ-11 connectors for the Cat-3 cabling for example an RJ-11 to RJ-45 cable ; RJ-11 pin # RJ-45 pin # 1 5 2 6 3 1 4 2 5 3 6 4 LAYER 1