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

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

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

Internet Protocol (IP) Background

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 1977-1979 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

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; http://www.ietf.org

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

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

Internet Protocol Suite

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

Network Interface Layer

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

Internet Layer

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

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

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

IP Address

IP Address A 32 bit number divided into octets where each octet has a value of 0-255; example 192.168.1.1 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 (email, web, DNS) use a static IP address and most clients (PC’s, Laptops, Cable Modems, etc) use dynamic addresses assigned via DHCP Example: 192.168.1.1 is the same as: 11000000.10101000.00000001.00000001 binary IP Addresses are assigned in blocks by ARIN (American Registry of Internet Numbers)

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. 192.168.1.1

IP Address 32 Bits Dotted Decimal Network Host 192 168 1 1 Maximum 1 8 9 16 17 24 25 32 11000000 10101000 00000001 00000001 Binary 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1

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

IP Address Classes Class A: Class B: Class C: Class D: 1 8 9 16 17 24 25 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 (128-191) 1 8 9 16 17 24 25 32 Bits: 110NNNNN Network Network Host Class C: Range (192-223) 1 8 9 16 17 24 25 32 Bits: 1110MMMM Multicast Group Multicast Group Multicast Group Class D: Range (224-239)

Network Mask

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. 255.255.255.0

Network Mask Default Mask for a Class A Network is 255.0.0.0, Default Mask for a Class B Network is 255.255.0.0, Default Mask for a Class C Network is 255.255.255.0 The Network Mask indicates how many bits are being used for the Network Portion of an Address

Network Mask Notations 10.0.0.0 mask 255.0.0.0 is equivalent to 10.0.0.0/8 172.16.0.0 mask 255.255.0.0 is equivalent to 172.16.0.0/16 192.168.1.0 mask 255.255.255.0 is equivalent to 192.168.1.0/24

Default Gateway

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. 170.10.0.0 to 192.1.1.0 or a different sub-network i.e. 192.168.1.64 to 192.168.1.128 Data must be forwarded through a gateway THIS FUNCTION IS NORMALLY DONE BY A ROUTER OR LAYER 3 SWITCH

Private IP Addresses

Private IP Address Space - RFC 1918 As defined in RFC 1918 Class A Address - Network 10.0.0.0 Class B Address - Networks 172.16.0.0 to 172.31.0.0 Class C Address - Range from 192.168.1.0 to 192.168.255.0 If you use any of these addresses in your network, then you MUST use address translation if you want to connect to the INTERNET

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: 10.0.0.0 to 10.255.255.255 Class B Private Addresses: 172.16.0.0 to 172.31.255.255 Class C Private Addresses: 192.168.0.0 to 192.168.255.255

Address Resolution

Host Addresses Every Host has at least 2 addresses… 1. A protocol address (i.e. IP address 172.16.1.1) 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

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 www.ietf.org Open Standards

ARP I heard that broadcast. The message is for me. Here is my Ethernet address. I need the Ethernet address of 172.16.3.2 IP: 172.16.3.2 = ??? 172.16.3.1 172.16.3.2 IP: 172.16.3.2 Ethernet: 0800.0020.1111 Now the IP Address is mapped to the MAC address, yielding a table like this: IP 172.16.3.2 : MAC 0800.0200.1111 Next time I want to talk to 172.16.3.2 I don’t have to use ARP since it’s already in my table.

Internet Control Message Protocol

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

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

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

Time To Live

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

TTL Host 2 Host 1 TTL = 10 TTL = 9 TTL = 6 TTL = 8 TTL = 7 20.1.1.1 10.1.1.1 Host 2 20.1.1.1 TTL = 10 TTL = 9 TTL = 6 TTL = 8 TTL = 7

Introduce a loop with broken routing TTL Host 1 10.1.1.1 Host 2 20.1.1.1 TTL = 10 TTL = 9 TTL = 0 TTL = 6 Introduce a loop with broken routing TTL = 8 TTL = 7

Transport Layer

Transmission Control Protocol - TCP IP protocol number 6 Connection oriented Reliable transport Assumes very little about the underlying protocol and architecture HTTP, Email, 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.

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.

Application Layer

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

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

Domain Name Service - DNS RFCs 1034 and 1035 Resolves hostname with domain to matching IP Address Easier to remember www.cisco.com than 198.133.219.25 Utilizes TCP and UDP as underlying Transport Protocols Alternative to Host Tables on all Hosts Domain Name Service www.ietf.org Open Standards

DNS - Name Resolution I heard that request. Here is the IP Address. www.cisco.com = 172.16.3.2 I need the IP Address for www.cisco.com www.cisco.com = ??? www.cisco.com = 172.16.3.2

IP Routing

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

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

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

General Networking Concepts

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

Unicast

Multicast

Quality of Service

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

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

Ethernet

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

Ethernet Overview Ethernet Speeds Ethernet - 10 Million Bits Per Second Fast Ethernet - 100 Million Bits Per Second Gigabit Ethernet - 1000 Million Bits Per Second or 1 Gbps Ten Gigabit Ethernet - 10000 Million Bits Per Second or 10 Gbps

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

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

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 00-00-0c Typical Formats 00-00-0c-12-34-56 0000.0c12.3456 00:00:0c:12:34:56

Putting it all Together

Putting It All Together… Information to transmit - Node A to Node B Determine which Protocol to use – TCP or UDP Name Resolution – www.cisco.com to 192.168.1.1 Address Resolution – 192.168.100.1 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

IPv6 Fundamentals

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

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

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)

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

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 => ::

Address Type Identification Localhost: 00..1 (128 bits) ::1/128 equivalent to 127.0.0.1 in IPv4 Multicast: 1111 1111 FF00::/8 Link-Local IPv6 Addresses 1111 1110 10 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)

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

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

Q and A

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

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

Contact Info Dan Baum Cisco Systems danbaum@cisco.com 469-255-2021