1. Understanding the Internet Protocol (IP) for RF Technicians
Dan Baum
Systems Engineer
Cisco
[date]

2. Objectives
Better understand the Internet Protocol’s (IP) background and popularity in today’s networks
Better understand the Internet Protocol Suite; including applications
Better understand a Router’s role in IP communications
Better understand the operation of IP in cable networks
Better understand the use of IP for delivering Voice, Video, Home Networking and other services
Gain a fundamental understanding of IP version 6

3. Agenda Internet Protocol (IP) background Internet Protocol Suite
IP applications and services
Routing IP
IP in cable networks
Using IP to deliver services
Introduction to IP version 6
Q&A

4. Internet Protocol (IP) Background

5. Internet Protocol History Lesson
Work began in mid 1970s for an internet technology
First packet-based switching network was ARPANET
Internet Protocols in current form took shape
The global Internet (what we have today) began in 1980
In 1983 the Office of the Secretary of Defense mandated that all devices connected to long haul networks use TCP/IP
In 1986 the National Science Foundation funded an effort to create a wide area backbone network called NSFNET and connected it to ARPANET
Today it is estimated there are over 1.4 Billion Internet users

6. IP Standards and Specifications
Based on open systems interconnection
No single vendor owns the TCP/IP technology
Publicly available
Facilitate communication between devices of diverse hardware architectures
Supported on multiple Operating Systems
Contained in Internet Request For Comments;

7. Why Use the Internet Protocol?
The Internet Protocol is the de facto standard for the Internet
Applications can quickly and easily be built upon an IP foundation
The Internet Protocol suite is an open specification allowing for interoperability
Resources for information related to IP are easy to find

8. What is the Internet Protocol?
Officially named the TCP/IP Internet Protocol Suite
Suite of protocols which define how devices communicate with each other
Facilitates communication between networks and devices of varying underlying technologies
Provides various Application Level Services
Electronic Mail
File Transfer
Terminal Emulation
Streaming Media
World Wide Web Based Services
Isn’t unique to the Global Internet; applies to private networks as well

9. Internet Protocol Suite

10. Internet Protocol Suite
OSI Layers
IPS Layers
Internet Protocol Suite
Application
FTP, TFTP, TELNET, SMTP, HTTP, DNS, BOOTP, TFTP, SNMP
Presentation
Application
Session
Transport
Transport
TCP or UDP (BGP and RIP)
Network
Internet
IP, ARP, ICMP, OSPF
Data link
Network Interface
Ethernet, Packet Over SONET,
Wireless
Physical

11. Network Interface Layer

12. Network Interface Layer
TCP/IP
Host
Host
The Internet or
Private Networks
Mutliple Layer 2
Technologies
Varying underlying technologies
- Ethernet
- Packet Over SONET
- Frame Relay
Different geographic locations
Talking Frames

13. Internet Layer

14. Internet Layer IP Packet format IP Address Network Mask
Default Gateway
Private IP Addresses
Address Resolution
Internet Control Message Protocol

15. IP Packet Format The Data is encapsulated in a Transport Protocol
Up to 1500 Bytes
IP Header
20 Bytes
Data
Variable Length
TCP or UDP Header
24 or 8 Bytes
The Data is encapsulated in a Transport Protocol
The process starts with Data to be transmitted
Then an IP Header is applied
IP Header
20 Bytes
TCP or UDP Header
24 or 8 Bytes
Data
Variable Length
FCS
4 Bytes
Ethernet Header
14 Bytes
Ethernet Header
14 Bytes
FCS
4 Bytes
The Ethernet frame with IP Packet is Transmitted
The Packet is then packaged in a Data Link frame

16. IP Header Information Version = 4 bits Length = 4 bits
20 Bytes
Version = 4 bits
Length = 4 bits
Type of Service (TOS) = 8 bits
Total Length = 16 bits
Identification = 16 bits
Flags = 3 bits
Fragment Offset = 13 bits
TTL = 8 bits
Protocol = 8 bits
Header Checksum = 16 bits
Source IP Address = 32 bits
Destination IP Address = 32 bits

17. IP Address

18. IP Address
A 32 bit number divided into octets where each octet has a value of 0-255; example
Uniquely identifies an IP enabled device on an IP network
It is common to use a dotted decimal representation of 4 octets
Addresses can be assigned Statically or Dynamically
Most servers ( , web, DNS) use a static IP address and most clients (PC’s, Laptops, Cable Modems, etc) use dynamic addresses assigned via DHCP
Example:
is the same as:
binary
IP Addresses are assigned in blocks by ARIN (American Registry of Internet Numbers)

19. IP Address An IP Address is 32 bits (or 4 bytes) in length
An IP Address is a UNIQUE identifier assigned to
EVERY device on a network. It is used to
allow communications between devices on
a network
An IP Address is 32 bits (or 4 bytes)
in length
It takes the form of
N.N.N.N
where N is a number from 0 to 255
e.g

20. IP Address
32 Bits
Dotted Decimal
Network
Host
192
168 1 1
Maximum 1 8 9 16 17 24 25 32
Binary

21. IP Address Classes Class A: Class B: Class C: Class D: Multicast
8 Bits
8 Bits
8 Bits
8 Bits
Class A:
Class B:
Class C:
Class D: Multicast
Class E: Research
Network
Host
Network
Host
Network
Host

22. IP Address Classes Class A: Class B: Class C: Class D: 1 8 9 16 17 2425 32
Bits:
0NNNNNNN
Host
Host
Host
Class A:
Range (1-126) 1 8 9 16 17 24 25 32
Bits:
10NNNNNN
Network
Host
Host
Class B:
Range ( ) 1 8 9 16 17 24 25 32
Bits:
110NNNNN
Network
Network
Host
Class C:
Range ( ) 1 8 9 16 17 24 25 32
Bits:
1110MMMM
Multicast Group
Multicast Group
Multicast Group
Class D:
Range ( )

23. Network Mask

24. Network Mask A Network Mask is 32 bits (or 4 bytes) in length
A Network Mask is associated with an IP Address and defines a boundary IP devices use to determine whether or not packets need to be forwarded to a Gateway
A Network Mask is 32 bits (or 4 bytes)
in length
It takes the form of
N.N.N.N
where N is a number from 0 to 255
i.e

25. Network Mask Default Mask for a Class A Network is 255.0.0.0,
Default Mask for a Class B Network is ,
Default Mask for a Class C Network is
The Network Mask indicates how many bits are being used for the Network Portion of an Address

26. Network Mask Notations
mask is equivalent to /8
mask is equivalent to /16
mask is equivalent to /24

27. Default Gateway

28. Default Gateway - Default Router
A gateway forwards data from the local
(sub) network to another (sub) network
When a IP host needs to communicate with another
IP host on a different IP network
i.e to
or a different sub-network
i.e to
Data must be forwarded through a gateway
THIS FUNCTION IS NORMALLY DONE BY A ROUTER OR LAYER 3 SWITCH

29. Private IP Addresses

30. Private IP Address Space - RFC 1918
As defined in
RFC 1918
Class A Address - Network
Class B Address - Networks to
Class C Address - Range from to
If you use any of these addresses in your network,
then you MUST use address translation if you want to connect
to the INTERNET

31. Private IP Address Space
Private addresses can be used in any network internally, they cannot be used for the global Internet
Class A Private Addresses: to
Class B Private Addresses: to
Class C Private Addresses: to

32. Address Resolution

33. Host Addresses Every Host has at least 2 addresses…
1. A protocol address (i.e. IP address )
2. A Media address (i.e. Ethernet MAC
address of the Network Interface Card 00:00:0c:12:34:56)
When a device wants to talk,
1. It uses the PROTOCOL address to identify the
device it wants to talk to, and..
2. The MEDIA address to send the data to the target device
or gateway on the same segment

34. Address Resolution Protocol - ARP
ARP works by broadcasting packets to all hosts attached to the LAN
ARP packet contains IP address in which sender is interested in communicating with
Hosts keep a list of ARP responses in an ARP table
ARP is propagated through Bridges/Switches but not through Routers
Address Resolution Protocol
Open Standards

35. ARP
I heard that broadcast. The message is for me. Here is my Ethernet address.
I need the Ethernet address of
IP: = ???
IP:
Ethernet:
Now the IP Address is mapped to the MAC address, yielding a table like this:
IP : MAC
Next time I want to talk to I don’t have to use ARP since it’s already in my table.

36. Internet Control Message Protocol

37. Internet Control Message Protocol - ICMP
IP protocol number 1
Used for troubleshooting
Error Reporting Mechanism
Notifies Hosts and Routers of presence and type of errors

38. Ping Packet InterNet Groper Check end-to-end network connectivity
Baseline network layer performance
Depending on implementation can indicate:
Host Alive
Roundtrip Delay

39. Traceroute
Used to determine path through a network between two endpoints
Uses the IP Time To Live (TTL) field
Initiated via Echo Request or UDP probe on high ports
Narrow down connectivity issues
Baseline network performance on a hop by hop basis

40. Time To Live

41. Time To Live - TTL Mechanism to prevent loops in an IP Network
Originating host sets the initial TTL value
Intermediate hops, i.e. routers, decrement the TTL value by 1
When TTL expires:
The packet is dropped
An ICMP report is sent back to the source

42. TTL Host 2 Host 1 TTL = 10 TTL = 9 TTL = 6 TTL = 8 TTL = 7 20.1.1.1
Host 2
TTL = 10
TTL = 9
TTL = 6
TTL = 8
TTL = 7

43. Introduce a loop with broken routing
TTL
Host 1
Host 2
TTL = 10
TTL = 9
TTL = 0
TTL = 6
Introduce a loop with broken routing
TTL = 8
TTL = 7

44. Transport Layer

45. Transmission Control Protocol - TCP
IP protocol number 6
Connection oriented
Reliable transport
Assumes very little about the underlying protocol and architecture
HTTP, , Telnet, FTP
TCP is a Transport Layer Protocol used to provide reliable, connection oriented communications between two devices. Each packet transmitted is acknowledged by the receiving station.

46. User Datagram Protocol - UDP
IP protocol number 17
Connectionless
Unreliable by nature
Upper layer applications responsible for reliability
Real time applications – VoIP, Video over IP
UDP is a Transport Layer Protocol used to provide fast, connectionless communications between to devices. Each packet transmitted is not acknowledged and reliability is left up to higher layer protocols and/or applications.

47. Application Layer

48. Dynamic Host Configuration Protocol - DHCP
RFC 2131
Protocol used to supply IP Layer information to Hosts
IP Address
Subnet Mask
IP Gateway
DNS Server(s)
Often used to simplify the management of IP Address Space
Prevents undertaking laborious task of manually configuring many Hosts

49. You can use this IP Address I will use that IP Address
DHCP
DHCPREQUEST
DHCPDISCOVER
DHCPOFFER
DHCPACK
Host
DHCP Server
I need an IP Address
You can use this IP Address
I will use that IP Address
Acknowledged

50. Domain Name Service - DNS
RFCs 1034 and 1035
Resolves hostname with domain to matching IP Address
Easier to remember than
Utilizes TCP and UDP as underlying Transport Protocols
Alternative to Host Tables on all Hosts
Domain Name Service
Open Standards

51. DNS - Name Resolution I heard that request. Here is the IP Address.=
I need the IP Address for
= ??? =

52. IP Routing

53. What is Routing?
Routing is the process of forwarding a datagram from one hop to the next
Routers forward traffic to a logical destination in an internetwork
Routers perform two primary functions
Routing – share/learn network routes
Switching – take packets from the inbound interface and send them through the outbound interface
Routers are a fundamental component to the very fabric of the Internet

54. Why are Routers Important?
Separate internetworks into logical entities
Maintain Routing information for end stations
Dynamically update Routing information as networks become available/unavailable
Determine the best path for communication through the internetwork

55. Why are Routers Important?
As the network topology changes, all routers will update their tables using their chosen routing protocol. (e.g. OSPF)
Routers make internetworking possible.
When a new link from Network 5 to Network 6 is established. The routers on Network 5 and 6 will advertise the new route to Network 3.
If the link from Network 5 to Network 3 breaks, the routers will update their tables and will choose the next best path which is now through Network 6.
I can now get to Network 6 directly!
I can no longer reach Network 3 directly!
Network 4
Network 1
Network 3 X
Network 5
I can now get to Network 5 directly!
Network 2
Network 6

56. General Networking Concepts

57. Packet Types Three types of Packets Unicast Multicast Broadcast
Only one end-point for the packet
Multicast
Only select endpoints (those who asked for it) should receive a copy of the packet
Broadcast
All end points should receive the packet

58. Unicast

59. Multicast

60. Quality of Service

61. TOS and DSCP
Type of Service (TOS) and Differentiated Services Code Point (DSCP)
Used to differentiate traffic types
Provide priority queuing to important packets
Originating host or intermediate routers can set TOS value
Intermediate routers can act upon (Per Hop Behavior) or modify the value
TOS has been expanded to Differentiated Services Code Point (DSCP) to provide more levels of service
TOS and DSCP are important to classify and prioritize services such as:
Voice over IP
Broadcast Video
Video on Demand
This ensures our customers have a pleasant TV viewing experience and coherent phone conversations

62. Sample ToS/DSCP Effect
Voice
10%
Low Latency, High Servicing (Voice)
Video
Broadcast Video
40%
High Speed Data
Data
50%
Step 1:
Define Scheduling
Step 2:
Define Bandwidth
Class definition sets minimum bandwidth
Queue servicing (metering) controls latency
Unused capacity is shared amongst the other classes
Each Class can be separately configured for QoS

63. Ethernet

64. Ethernet Overview Invented by Xerox in Early 1970’s
Became IEEE Standard in 1980’s
Ethernet Version 2 Jointly Developed by Digital Equipment Corp, Intel Corp, and Xerox
Popular as a Layer 2 Protocol

65. Ethernet Overview Ethernet Speeds
Ethernet - 10 Million Bits Per Second
Fast Ethernet Million Bits Per Second
Gigabit Ethernet Million Bits Per Second or 1 Gbps
Ten Gigabit Ethernet Million Bits Per Second or 10 Gbps

66. Data Payload (IP) Up to 1500 Bytes
Ethernet Overview
Destination MAC Address
Ethernet Frame
Dest
Addr
Src
Addr
Type
FCS
Data Payload (IP) Up to 1500 Bytes
Source MAC Address
Frame Check Sequence (CRC)
Type field
IPv4 = x0800

67. Why Ethernet?
Gigabit Ethernet and Ten Gigabit Ethernet offer high throughput capabilities
Ethernet relatively inexpensive compared to other technologies offering the same throughput
Ethernet is well known and understood; resources abound

68. MAC Address MAC = Media Access Control Hardware identifier
Burned in at time of manufacturing
6 Bytes in length
Uniquely identifies devices connected to Ethernet
Organization Unit Identifier is first 3 bytes
Example: Cisco has OUI of c
Typical Formats c
0000.0c
00:00:0c:12:34:56

69. Putting it all Together

70. Putting It All Together…
Information to transmit - Node A to Node B
Determine which Protocol to use – TCP or UDP
Name Resolution – to
Address Resolution – to 00:00:0c:12:34:56
Send Information to local Router to get on the Network
Router determines QoS tag and queues appropriately
Information flows from Hop to Hop (Router to Router) until it reaches the destination

71. IPv6 Fundamentals

72. What changed from IPv4? Expanded address space
Addresses quadrupled from 32 bits to 128 bits
Header Format Simplification
Fixed length, optional headers are daisy chained
IPv6 header is double that of IPv4, from 20 to 40 bytes
No checksum at the IP network layer
Relies on lower layer (POS, Ethernet, etc) or upper application layer (TCP, UDP)
No hop-by-hop segmentation/fragmentation
Path MTU discovery mandated
No broadcast

73. IPv4 & IPv6 Header Comparison
IPv6 Header – RFC 2460
Version
IHL
Type of Service
Total Length
Identification
Flags
Fragment Offset
Time to Live
Protocol
Header Checksum
Source Address
Destination Address
Options
Padding
Version
Traffic Class
Flow Label
Payload Length
Next Header
Hop Limit
Source Address
Destination Address
- field’s name kept from IPv4 to IPv6
- fields not kept in IPv6
- Name & position changed in IPv6
- New field in IPv6
Legend

74. Larger Address Space IPv4 IPv6 32 bits
= 4,294,967,296 possible addressable devices
IPv6
128 bits
=3.4 X 1038 possible addressable devices
=340,282,366,920,938,463,463,374,607,431,768,211,456
5 x 1028 addresses per person on the planet
13 quintillion IPv4 domains per person
(a quintillion is one million trillion)

75. IPv6 Addressing IPv6 addressing rules are covered by multiple RFC’s
Architecture defined by RFC 4291
3 Address types:
Unicast: One to One (Global and Link Local)
An identifier for a single interface. A packet sent to a unicast address is delivered to the interface identified by that address.
Anycast: One to Nearest (Allocated from Unicast)
An identifier for a set of interfaces (typically belonging to different nodes). A packet sent to an anycast address is delivered to one of the interfaces identified by that address (the "nearest" one, according to the routing protocols' measure of distance).
Multicast: One to Many
An identifier for a set of interfaces (typically belonging to different nodes). A packet sent to a multicast address is delivered to all interfaces identified by that address.
No Broadcast address, use multicast instead

76. IPv6 Address Representation
All addresses are 128 bits.
16-bit fields in case insensitive colon hexadecimal representation – Preferred form
2031:0000:130F:0000:0000:09C0:876A:130B
Leading zeros in a field are optional:
2031:0:130F:0:0:9C0:876A:130B
Successive fields of 0 represented as ::, but only once in an address – Compressed form
2031:0:130F::9C0:876A:130B
2031::130F::9C0:876A:130B
0:0:0:0:0:0:0:1 => ::1
0:0:0:0:0:0:0:0 => ::

77. Address Type Identification
Localhost: (128 bits) ::1/128
equivalent to in IPv4
Multicast: FF00::/8
Link-Local IPv6 Addresses x x FE80::/10
(FE80, FE90, FEA0, FEB0)
Used within a network segment
Global Unicast: Everything else
All address types (except multicast) have to support EUI-64 (64 bit extended unique identifier)

78. IPv6 Global Unicast Addresses
IPv6 Global Unicast addresses are:
Addresses for generic use of IPv6
Structured as hierarchy to keep the aggregation
First 3 bits 001 (2000::/3) is the first allocation from IANA for IPv6 Unicast use
001
Global Routing
Prefix
Subnet ID
Interface ID
n bits
Provider
(64-n) bits
Site
64 bits
Host

79. IPv6-enable Application
Dual Stack Approach
IPv6-enable Application
IPv4 Application
Preferred method on
Application servers
TCP
UDP
TCP
UDP
IPv4
IPv6
IPv4
IPv6
Frame Protocol ID
0x0800
0x86dd
0x0800
0x86dd
Data Link (Ethernet)
Data Link (Ethernet)
Dual stack node means:
Both IPv4 and IPv6 stacks enabled
Applications can talk to both
Choice of the IP version is based on name lookup and application preference
* Does not mean that all applications are dual stack aware

80. Q and A

81. References http://www.ietf.org
RFC 761 – DoD Standard Transmission Control Protocol
RFC 768 – User Datagram Protocol
RFC 791 – Internet Protocol
RFCs 1034 and 1035 – Domain names – concepts and facilities, Domain names – implementation and specification
RFC 1918 – Address Allocation for Private Internets
RFC 2131 – Dynamic Host Configuration Protocol

82. References cont.
RFC 2460 – Internet Protocol, Version 6 (IPv6) Specification
RFC 4291 – IP Version 6 Addressing Architecture
Internetworking with TCP/IP by Douglas E. Comer

83. Contact Info
Dan Baum
Cisco Systems