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TCP/IP: Concepts and IP Routing

An introductory course in two modules, first taught in 1999 and updated for this 2026 edition, in English and Brazilian Portuguese

A complete introductory training on how internetworks work and how IP finds its way across them: from bridges, routers and the routing algorithms, through the TCP/IP stack, addressing, ARP and a packet followed hop by hop, to RIP, EIGRP, OSPF, IS-IS and BGP-4, access lists, IPv6, multicast, MPLS and VRRP. Every one of the 178 slides carries speaker notes, so the course can be taught from the deck, or learned from it, without anyone else in the room.

Based on a course Rodolfo Nützmann first taught in March 1999, and rebuilt in 2026: 16:9 slides with the diagrams redrawn as native, editable shapes, the content updated to current practice (CIDR in place of address classes, EIGRP in place of IGRP, BGP-4, IPv6 as RFC 8200 defines it, PIM, VRRPv3), and the historical topics kept for their teaching value and marked LEGACY.

The course's cover slide: TCP/IP: Concepts and IP Routing, modernized 2026 edition (US English), by Rodolfo Nützmann, based on the "TCP/IP Concepts" course presented at Technology Week in March 1999.
Click on the cover to present the deck

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At a glance

Level
Introductory, from first principles to the routing protocols
Format
Slides (PDF) and editable deck with notes (PPTX)
Slides
178 per edition, the same slides in both languages
Speaker notes
On all 178 slides, in both languages
Languages
English (US) and Portuguese (Brazil)
Edition
2026
First taught
1999
Price
Free, no sign-up
Licence
CC0 1.0 Universal, a public-domain dedication

Who it is for

Learners. Read the PDF straight through, or open the PPTX in presenter view and read the notes as the commentary the instructor would give. The objectives at the start of each module and the summaries at the end tell you what you should be able to explain.

Instructors. The notes are written to be taught from: what to say on each slide, what to ask the class, where the common confusions are, and what changed since 1999. The deck is fully editable, the diagrams included, and the closing slides list the RFCs and sources by topic, so you can prepare yourself before you prepare a class.

A look inside

6 of the 178 slides, chosen for their diagrams. Each one opens at full size.

  • Diagram: network A attached to router R1, with R2 and R3 in a line beyond it, each router's table for A beneath it (metric 0 direct, 1 via R1, 2 via R2), advertisements flowing outwards and R3's advertisement back to R2 ignored.
    The slow convergence problem (count to infinity)Slide 26 · Part 1: General routing concepts
  • Diagram: hosts A (172.16.10.1) and B (172.16.10.200) and a third station C on one Ethernet link, subnet 172.16.10.0/24; A's ARP request crosses the whole link, sent to the broadcast address FF-FF-FF-FF-FF-FF.
    ARP, local host (3 of 6): ARP Request in broadcastSlide 79 · Part 3: Internet Protocol behavior
  • Diagram: host A on 172.16.25.0/24 sends to router X on its way to host B on 172.16.27.0/24 through router W; beneath, the Ethernet frame (destination MAC of X, source MAC of A, type 0x0800) and the IP packet (TTL 64, protocol 6, source A, destination B), field by field.
    Step 1: A sends the initial packetSlide 97 · Part 4: IP in a routed internetwork: a complete example
  • Diagram: area 0, the backbone, joined through three area border routers to area 1, area 2 and a stub area n.
    OSPF topology: backbone and areasSlide 121 · Part 5: IP routing protocols
  • Diagram: a source behind first-hop router R1 and a receiver behind last-hop router R4, the rendezvous point above them and R3 on the shortest path below, with the four steps numbered: the join to the shared tree, the source's registration, the native path to the RP and the switchover to the shortest-path tree.
    PIM-SM in operation: RP, shared tree and SPTSlide 166 · Part 9: IP multicast
  • Diagram: routers R1 (priority 120, master) and R2 (priority 100, backup) share virtual router 10 at 172.16.20.1, the gateway of four hosts on VLAN 20; R1 advertises every second to 224.0.0.18, and when R1 fails, R2 takes over the virtual MAC after about three seconds.
    VRRP in operation: a failover exampleSlide 174 · Part 10: MPLS and VRRP

Want this course taught live?

Rodolfo Nützmann teaches it as an instructor-led class for teams, on site or virtual, in English or Portuguese: a field veteran of three decades who teaches for a living, with real demonstrations and hands-on labs that take the subject past the slides.

Ask about a class →

Course outline

Slides 1 to 3 open the course (the title, the agenda and the 1999 to 2026 comparison below); slides 176 and 177 list the RFCs and sources by topic; slide 178 closes it.

Module 1

  1. Part 1 · slides 4 to 41

    General routing concepts

    Present this part →
    • Heterogeneity and the components of an internetwork
    • Interconnection devices and the OSI model
    • Bridges and Layer 2 switches, the broadcast domain and Spanning Tree
    • Routers: data flow, advantages and limitations
    • Routable and nonroutable protocols
    • Network-layer against data-link addressing, and encapsulation
    • Static and dynamic routing
    • Distance vector: metrics, count to infinity, split horizon, poison reverse, hold-down and triggered updates, with a worked example
    • Link state: principles, advantages and the protocols in use
    • Autonomous systems

Module 2

  1. Part 2 · slides 42 to 66

    TCP/IP

    Present this part →
    • Origin and governance of TCP/IP
    • The stack against the OSI model: application, transport and internet layers
    • The IPv4 datagram in detail, protocol and port numbers, demultiplexing
    • Decimal-to-binary conversion and the IPv4 address
    • Classful addressing (legacy), CIDR and special-purpose addresses
    • Subnets, the subnet mask and comparison under mask
    • VLSM, with an addressing plan for a /24

  2. Part 3 · slides 67 to 93

    Internet Protocol behavior

    Present this part →
    • Route determination: local or remote, with the AND
    • Next-hop gateway lookup
    • ARP (RFC 826) step by step, for a local and a remote host, with the request and reply packets
    • Proxy ARP, with a worked example
    • ARP in 2026: gratuitous ARP, the cache, security and IPv6

  3. Part 4 · slides 94 to 104

    IP in a routed internetwork: a complete example

    Present this part →
    • The topology and the six-step data transfer, hop by hop
    • Host names: from the hosts file to DNS
    • Proxy ARP: vendor defaults

  4. Part 5 · slides 105 to 134

    IP routing protocols

    Present this part →
    • RIP: origin, variants and the RIPv2 message
    • Administrative distance
    • From IGRP to EIGRP: the composite metric, DUAL and multipath
    • Route redistribution and its risks
    • OSPF: areas, router types, network types, Hello, adjacencies, DR and BDR, LSAs and the LSDB, inter-area and external routes
    • OSPFv3 and IS-IS
    • Interior against exterior protocols, EGP, and BGP-4 attributes and best-path selection

  5. Part 6 · slides 135 to 140

    Controlling IP access

    Present this part →
    • ACLs in the router's processing flow
    • Standard ACL examples: permit the internal network, deny a host, deny a subnet
    • ACLs in 2026: extended, named, IPv6 and stateful firewalls

  6. Part 7 · slides 141 to 145

    Additional IP routing topics

    Present this part →
    • IP broadcast handling and the DHCP problem
    • DHCP relay and directed broadcast
    • Secondary addresses
    • Unnumbered interfaces

  7. Part 8 · slides 146 to 157

    IPv6: from 'IPng' to the dominant protocol

    Present this part →
    • From 'IPng' (1995) to RFC 8200 (2017)
    • The differences from IPv4, the header and the extension headers
    • Addressing: 128 bits, three types, no broadcast; types and scopes
    • Neighbor Discovery and SLAAC
    • Routing, flows and traffic class, security
    • IPv4 and IPv6 transition and coexistence

  8. Part 9 · slides 158 to 167

    IP multicast

    Present this part →
    • Multicast addresses and their mapping to MAC addresses
    • IGMP and MLD
    • Dense against sparse mode and the RPF check
    • Multicast routing protocols, and PIM-SM: the RP, the shared tree and the SPT
    • RSVP, and what is left of it

  9. Part 10 · slides 168 to 175

    MPLS and VRRP

    Present this part →
    • Label switching and its terminology
    • FIB, LIB and LFIB, with an example
    • MPLS applications in 2026
    • VRRP: default gateway redundancy, with a failover example
    • The Module 2 summary

Learning objectives

Module 1

  1. Internetworking vocabulary. Recognize the basic internetworking terms and concepts: LAN and WAN links, interconnection devices, broadcast and collision domains.
  2. Bridges and switches versus routers. Compare the operation of bridges/Layer 2 switches and routers, and understand Layer 2 and Layer 3 switching.
  3. Routable protocols. Describe the properties of a routable protocol and put nonroutable protocols in historical context.
  4. Distance vector. Explain the principle of operation, the inherent instability (slow convergence) and the techniques that correct it.
  5. Link state. Explain SPF (Dijkstra) algorithms, their advantages over distance vector and the protocols that implement them.
  6. Autonomous systems. Define autonomous system and distinguish interior from exterior routing protocols.

Module 2

  1. Characteristics of TCP/IP. Protocol stack, IPv4 datagram, protocol and port numbers, addressing, subnetting and VLSM, host-to-host communication, ARP and Proxy ARP.
  2. The IP routing process. Describe in detail, step by step, what happens to a packet between the source station and the destination station in a routed internetwork.
  3. RIP and EIGRP. Recall the fundamentals of RIP (v1, v2, RIPng) and of EIGRP (composite metric, DUAL, multipath) and the role of administrative distance.
  4. Redistribution and OSPF. Discuss route redistribution between routing processes and recall the principles of OSPF (areas, router types, Hello, DR, LSAs).
  5. BGP-4. Distinguish interior from exterior protocols and describe the fundamentals of BGP-4 (path vector, eBGP/iBGP, attributes).
  6. Access control. Recall how access control lists (ACLs) on routers filter IP traffic, and how they evolved into stateful firewalls.
  7. Operational topics. Broadcast handling (DHCP relay), secondary addresses, unnumbered interfaces, static and default routes.
  8. IPv6 and complementary technologies. Understand IPv6 (header, addressing, ND/SLAAC, routing, transition), IP multicast (IGMP/MLD, PIM), RSVP, MPLS and VRRP.

From 1999 to 2026

TopicIn 1999In 2026
LAN linksEthernet 10/100, Token Ring, FDDIEthernet 1G to 400G, Wi-Fi 6/7; Token Ring and FDDI extinct
Network protocolsTCP/IP, IPX, AppleTalk, DECnet, SNAIP only (IPv4 and IPv6); the rest is legacy
IPv4 addressingClasses A/B/C, contiguous subnetsCIDR/VLSM (RFC 4632); IPv4 exhaustion (IANA 2011, LACNIC 2020); NAT and CGNAT
IPv6"IPng" in draft (RFC 1883)RFC 8200 (2017); > 50% of Google access (Mar 2026); Brazil ≈ 59% (APNIC, Oct 2026)
IGPRIP, IGRP, OSPFOSPFv2/v3, IS-IS, EIGRP (RFC 7868); RIP only in small networks
EGPEGP on the way out, BGP-4 arrivingBGP-4 (RFC 4271) universal; 32-bit ASNs (RFC 6793)
MulticastDVMRP, MOSPF, MBonePIM-SM/SSM (RFC 7761, RFC 4607), IGMPv3/MLDv2
Gateway redundancyVRRP just published (RFC 2338)VRRPv3 (RFC 5798) for IPv4 and IPv6; HSRP
Layer 2 interconnectionBridges, STP 802.1DMultilayer switches, RSTP/MSTP, 802.1Q VLANs, EVPN

The comparison is slide 3 of the course itself, with the figures its notes say were verified in October 2026.

Downloads

FileSizeSHA-256Download
English (US) · PDFReader's edition: the slides, for reading and printing1.3 MB1200491e565cc2d00b99465b01d925c9b4a67d02563eb54a8d77d13ec5ab2355DownloadRead online
English (US) · PowerPoint (PPTX)Instructor's edition: the editable deck with the speaker notes0.8 MBef51eb558de1d2e088005685d8d1d209ea08f9bba9b2ab59c8981a00957fbf95Download
Portuguese (Brazil) · PDFReader's edition: the slides, for reading and printing1.8 MB7a7cc379826e60fb864026bc948cbc632c7b764d5f87b36a95cec339ef0beb9aDownloadRead online
Portuguese (Brazil) · PowerPoint (PPTX)Instructor's edition: the editable deck with the speaker notes0.8 MB43ea465cb39750947836b69a9620349605666667da82b24f9f92b360a217d72eDownload

Licence

Offered under CC0 1.0 Universal. You can copy, modify, translate, distribute and teach with this course, commercially or not, without asking permission.

Credit to Rodolfo Nützmann is appreciated, never required. As the CC0 deed asks, do not imply endorsement by the author when you use the material.

Read the CC0 1.0 deed ↗

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