1. CN2668 Routers and Switches Kemtis Kunanuraksapong MSIS with Distinction MCTS, MCDST, MCP, A+

2. Agenda Chapter 3: TCP/IP Exercise Quiz

3. Overview of the TCP/IP Transmission Control Protocol/Internet Protocol ▫A protocol suite TCP/IP Model ▫Application ▫Transport (TCP and UDP) ▫Internetwork (IP Address) ▫Network Interface ▫See Figure 3-1 on Page 55

4. Application Layer Includes protocol for e-mail, remote logins, files transfer, web browsing, etc ▫FTP/TFTP ▫NFS (Network File System) ▫SMTP ▫Telnet ▫DNS ▫HTTP

5. Transport Layer Performs end-to-end packet delivery, reliability, and flow control ▫TCP ▫UDP Ports ▫Well known Ports (1 – 1023) ▫Registered Ports (1024 – 49151) ▫Dynamic/Private Ports (49152 – 65535)

6. TCP Three-Way Handshake See Figure 3-3 on Page 59 ▫Src Port/Dest Port ▫Seq. Nmber ▫Ack. Number Initial sequence numbers (ISN) is required before two computers can communicatate ▫Host A send SYN to Host B ▫Host B send ACK to Host A ▫Host A send ACK to Host B ▫See Figure 3-4 on Page 60

7. TCP Sliding Windows Sliding windows control the flow and efficiency of communication ▫After three-way handshake is complete ▫Allows multiple packets to be sent and affirmed with a single ACK packet ▫Sender control the window’s size

8. Flow control method TCP Sliding Windows Buffering ▫Store packets in the memory Congestion avoidance ▫Slow down the transmission rate request

9. Internetwork Layer Handles software (logical) addressing Four main protocols ▫IP ▫ICMP ▫ARP (Address Resolution Protocol)  Resolves IP address to MAC for source hosts ▫RARP  Replaced by DHCP

10. Internetwork Layer (Cont.) ARP Tables ▫Maintain in volatile RAM ▫Contains MAC and IP addresses of other devices on the network ARP Request ▫Source host broadcast request when it can’t find the matching in the cache/ ARP Table. (Knows IP but no MAC)

11. Internetwork Layer (Cont.) ARP Request Frame ▫See Figure 3-7 on Page 65 ▫Actual packets have 28 octets ▫Destination MAC is FF:FF:FF:FF:FF:FF ▫The destination send ARP reply back as unicast 2 to 10 minute cache life ▫If used twice in the first 2 minutes, then it is extend to 10 minutes

12. Internetwork Layer (Cont.) RARP ▫Same as ARP, except that it used for diskless machine ▫A client IP must be stored on a RARP server RARP Request Frame ▫See Figure 3-8 on Page 66 RARP Client ▫Receives a RARP reply from server and copy IP’s configuration to RAM till it’s reboot or shutdown

13. Internetwork Layer (Cont.) Routers and ARP ▫Router maintain ARP table Ping Utility ▫Use ICMP echo request/reply messages ▫! means ping success ▫See Table 3-1 on Page 68 for Ping responses ▫Standard Ping and Extended Ping  See Figure 3-10 on Page 69

14. Internetwork Layer (Cont.) Trace Utility ▫Uses ICMP echo request/reply messages ▫Shows the exact path a packet takes from the source to destination

15. Frame Transmission The frame are sent to router when the packet is not on their segment Router remove the MAC address and determine which segment to forward the packet

16. Dynamic or Static Tables Static Table ▫Has to be update manually by Network Admin Dynamic Table ▫Update are provided through routing protocols ▫Distance-vector algorithm  Considers the number of hops between two points ▫Link state algorithm  Consider network traffic, connection speed, and other factors

17. Routing Packets See Figure 3-14 on Page 74 ▫Host A send packet to Router A ▫Router 1 analyze the packet then forward to Router 2  Router strip the Network Interface layer information off the packet.  Check the routing table for destination port  Repack the packet with new MAC (MAC of Router 2) ▫Router 2 do the same and forward to Router 3 ▫Router 3 analyze and send it to Host B

18. Cisco Three-Layer Hierarchical Core Layer ▫Responsible for switching large amounts of data quickly and efficiently Distribution Layer ▫Provides networking services such as NAT, Firewall, QoS ▫IP addressing is managed at this layer Access Layer (Desktop Layer) ▫Workstations / printers / End node See Figure 3-15 on Page 77

19. Assignment Review Questions ▫1 – 22 Case Projects ▫1, 2