1. The Network Layer Forwarding –Internal path to follow Routing –External path to follow Models –Guaranteed delivery with or without bounded delay –In-order packet delivery –Guaranteed minimal bandwidth –Guaranteed maximum jitter

2. test

3. Virtual Circuits Connection Oriented Connection state information Phases –VC Setup –Data Transfer –VC Teardown

4. Datagram Networks Internet Not connection oriented No guarantee of delivery Faster

5. Routing Address 129.123.3.0Interface 0 Address 129.123.7.0Interface 1 Address 129.123.7.40Interface 2 Address 129.123.63.0Interface 3 Address 129.123.73.0Interface 4

6. Routers

7. Router Switching

8. Queueing Packet Scheduling Quality of Service Active Queue Management

9. Router Configuration http://www.cs.usu.edu/~bobw/cs4720/CISCO.txt Lookup –Helper addresses Forwarding Queueing Other protocols –IPX/SPX (Novell, Microsoft) –Appletalk (Macintosh) –DECnet (card readers)

10. Routing on the Internet RIP (Routing Internet Protocol) –Lots of traffic (advertisements) –Not very efficient –Basically obsolete OSPF (Open Shortest Path First) –Flooding –Secure –Multiple same cost paths –Multicast and Unicast capable

11. Router Monitoring Traceroute (tracert) –Simple routing test USU’s Web site for monitoring: http://pomoxis.usu.edu/~network/grapher.cgi?target=%2Fnetwork-devices%2Frouter-interfaces What’s UP http://floyd.usu.edu

12. IP Network Communication IPv4 Addressing Network Layer (IP, Layer 3) Protocols are described in RFCs (Request for Comments) Available from nis.nsf.net/internet/documents/rfc TCP/IP Addressing –Class A (1-126).xxx.xxx.xxx –Class B (128-191).(assigned).xxx.xxx –Class C (192-223).(assigned).(assigned).xxx

13. Internet Addressing Each address is 4, 8 bit, decimal numbers Like Area Code/Exchange/Subscriber 129.123.7.170 129.123 is assigned to USU (domain) 172.xxx.xxx.xxx USU nonroutable 7 is assigned to Computer Science 170 is assigned to PC named java4 Every Internet device must have a number Number to name conversion is done by DNS

14. IP header Version number (4 bits) –Tells router how to interpret datagram Type of Service –Selects delivery speeds vs. accuracy Datagram Length (16 bits) rarely longer than 1500 bytes Identification, Flags and Fragment offset –Reassembly of a fragmented datagram Time to Live –Router hops, control routing loops Protocol (TCP,ICMP, UDP) Header Checksum Source and Destination IP addresses

15. VersionLengType of SvcTotal Length IdentificationFlags Frag Offset Time to Live ProtocolHeader Checksum IP Header Source Address Destination Address TCP Header then your data...

16. IP Fragmentation Not all routing systems utilize 1500 byte packets. PPP (dialup) sizes are 576 bytes. Like TCP frames, IP frames need to be reassembled in order even if one packet is lost.

17. IP Fragmentation

18. Subnets Class A 255.0.0.0 Class B 255.255.0.0 –USU uses 255.255.255.0 for subnetting buildings Class C 255.255.255.0 Subnet Masks –129.123.0.0/16 –129.123.7.0/24

19. Flat vs. Routed Networks Flat network –Enormous party line –Systems move freely around enterprise –Simple and cheap to implement Routed network –Require subnetting –Control packet flow –Systems must readdress as they move

20. Subnetting

21. Obtaining a host address Number Assignment –(http://www.networksolutions.com)http://www.networksolutions.com –Whois Number registration: http://thingy.usu.eduhttp://thingy.usu.edu Manual configuration –Inserting IP numbers for subnet, router, nameserver Dynamic Host Configuration Protocol –Dynamic versus Static IP addressing –Discussed in next weeks presentation

22. ICMP Ping Router information

23. Network Address Translation (NAT) Protects internal systems –Makes internal systems invisible Recycles Internet Addresses (IP) Uses nonroutable IP addresses –10.xxx.xxx.xxx –172.xxx.xxx.xxx –192.xxx.xxx.xxx

24. IP Version 6

25. Conversion to IPv6 Addressing –3ffe:ffff:0100:f101:0210:a4ff:fee3:9566 –Compatibility: ::ffff:w.x.y.z Dual Stack Tunneling

26. IPv6 Extended address capabilities Streamlined header Flow labelling No fragmentation or reassembly No header checksum (redundant) No options

27. Broadcasting and Multicasting Uncontrolled Flooding –Copy of each packet to all neighbors –Can cause broadcast storms Controlled Flooding –Sequence number controlled flooding –Reverse path forwarding Spanning Trees

28. Multicasting

29. Types of Multicast Management Protocols Internet Group Management Protocol Distance-Vector Multicast Routing Protocol Protocol-Independent Multicast protocol

30. Applications of Multicast Online conferencing (mbone) –Video –Sound System Imaging –Symantec Ghost –Powerquest DriveImage

31. IP Layer The End Remember Homework 2 from the Website