IPv6 … A Simplified Explanation

Presented byBryan Crisler

Senior Network EngineerTime Warner Cable

Housekeeping

• Take this time to locate:– Emergency Exits– Bathrooms– Breakroom/Water Fountain– Note taking utensils

• Put your Phones on Vibrate– If you need to take a call, feel free to

step out of the room.

About your Speaker

• Bryan Crisler– Started in Cable @ Charter

Communications, Riverside, CA in June 2005

– Currently a Senior Network Engineer at Time Warner Cable

About your Speaker

• Held following positions:– Broadband Technician I-IV (Charter)– Network Operations Specialist

(Charter)– Network Technician (Charter)– Network Engineer (Charter & TWC)– SR Network Engineer (TWC)

About your Speaker

• Email: bryan.crisler@twcable.com• LinkedIn: linkedin.com/in/bcrisler

Today’s Lesson Plan

• Session 1: So What About IPv6?• Session 2: Every Day IPv6 and You

So What About IPv6?

Session 1

Basic History of IP

• IP – Internet Protocol• Defined in RFC 791, dated 1981, written

by Information Sciences Institute @ USC• Written for DARPA (Defense Advanced

Research Projects Agency)

Basic History of IP

• “… Internet Protocol is designed for use in interconnected systems of packet-switched computer communication networks…provides for transmitting blocks of data called datagrams from sources to destinations… identified by fixed length addresses.” (RFC 791, section 1.1)

Versions of IP• IPv0 – 3: Experimental Only• IPv4: Defined in 1981 by RFC 760 &

791. First version to implemented publically. Still in use today.

• IPv5: Also experimental, called Internet Stream Protocol.

• IPv6: Also called IP Next Generation (IPng), Defined in 1998 by RFC 2460-2467

IP Addressing

• Layer 3 (Network) form of Addressing• Two different forms of IP Address:

– IPv4• Uses Dotted Decimal (192.168.0.1)• Has 4,294,967,296 total address (public &

private)• 32 bit address

– IPv6• Uses Hexadecimal Notation (FE80::1)• Has 3.4×1038 total address (public & private)• 128 bit address

IP Addressing – cont.

• Both versions represent a real number• For Instance:

– 0.0.1.0 = 256– 10.0.0.4 = 16,777,220– 0:0:0:0:0:0:0:1 = 1– 0:0:0:0:1:0:0:0 =

281,462,092,005,375

IP Addressing – cont.

• IPv4 Address:– Dotted decimal notation– x.x.x.x, where x is between 0 – 255

• IPv6 Address– Hexadecimal Number system– 0000:0000:0000:0000:0000:0000:0000:0000– Leading Zeros can be removed– Multiple blocks of zeros can be simplified

using colon “:”

IP Addressing – cont.

• Blocks of IPs are called Subnets• Each Subnet represents a network (either WAN

or LAN)• The range of each subnet is determined by the

Subnet Mask• Each Subnet has a Network (First IP address)

and a Broadcast (Last IP Address, IPv4 only) IP Address

• Network Range is calculated Subtracting Subnet Mask and from 255.255.255.255 (IPv4) or by 2^(128 – prefix) (IPv6).

IP Addressing – cont.

• Network Address: First IP in a Subnet used to identify the entire network

• Broadcast Address (IPv4 only): Last IP in a Subnet used to communicate any device on the Useable IP Range.

• Gateway IP Address: The configured IP address on the next hop router, which contains a path towards a WAN/Internet

• Useable IP Range: Any IP in a subnet except the Network and Broadcast (IPv4 only)

IPv4 Address Example

• A home wireless Router is configured with network address of 192.168.0.0 and a subnet mask of 255.255.255.0

• 255.255.255.255 – 255.255.255.0 = 0.0.0.255 = 256 total addresses

• 192.168.0.0 + 0.0.0.255 = 192.168.0.255

• Network Range: 192.168.0.0 to 192.168.0.255

• Network Address: 192.168.0.0• Broadcast Address: 192.168.0.255

IPv6 Address Example

• A home wireless router has received a prefix delegated scope from the ISP 2605:e000:160e:816a::/64.

• 2^(128 - prefix) 2^64 -> 18,446,744,073,709,551,616 hosts

• Approximately 18.4 Quintillion IP Addresses.

• If each IP address was the size of a quarter, you could cover the entire earth approximately 24 times.

IPv6 Address Example – cont.• The network Range is

– 2605:e000:160e:816a:0000:0000:0000:0000 -2605:e000:160e:816a:ffff:ffff:ffff:ffff

• Network Address: 2605:e000:160e:816a:0000:0000:0000:0000• Broadcast Address: There is no

broadcast address, since multicast is used instead.

IPv4 vs IPv6: ComparisonIPv4 IPv6

Address 32-bit 128-bit

Number of Addresses

4,294,967,296340,282,366,920,938,463,463,374,607,4

31,768,211,456

Network Address X X

Broadcast Address X N/A

Link-Local Range 169.254.0.0/16 FE80::/10

Multicast Range224.0.0.0 –

239.255.255.255FF00::/8

Dynamic Addressing DHCP SLAAC or DHCPv6

Security OptionalIPSec built-in,

optional

Header Length Variable Fixed

IPv4 vs IPv6: Comparison – cont.

IPv4 IPv6

Loopback Address 127.0.0.1/32 ::1/128

Default Gateway 0.0.0.0/0 ::/0

IGP Routing Protocols

RIP (v1/v2), OSPF, ISIS, EIGRP

RIPng, OSPFv3,ISIS

EBGP Routing Protocols

BGP BGPv4

Other Protocols ICMP, DHCP, DNSICMPv6, DHCPv6,

DNS

IPv6 Features

• Larger Address Space• Simplified header makes routing more

efficient• Private IP Space not required• Manual configuration not required due

to SLAAC• Broadcasting of packets replaced with

Multicast/Anycast

IPv6 Features – cont.

• Security built into IPv6, but is optional• Mobility allows for devices to use the

same IPv6 Address (from home network) regardless of what network they are connected to.

• Dual Stack / 6 to 4 tunneling is available to provide a smooth transition

ARP vs Neighbor Discovery Protocol• ARP – Address resolution protocol uses IPv4 Broadcast

address to map an IPv4 Address to a MAC address (ARP) or vise versa (rARP).

• Neighbor Discovery Protocol – part of the ICMPv6 protocol, uses multicast to establish communication with devices on the same network segment. Follows the following process:– Neighbor Solicitation: sends a message to FF02::1/16

with all configured IPv6 addresses– DAD (Duplicate Address Detection): If no message is

received from LAN segment, configured IPv6 Addresses are assumed not to be duplicates.

– Neighbor Assignment: Message sent to confirm configuration of IPv6 addresses to LAN segment.

ARP vs Neighbor Discovery Protocol – cont.• NDP – cont.

– Router Solicitation: message sent to FF02::2/16 to detect presence of routers on network segment. Determine the default gateway for host.

– Router Advertisement: response from router

– Redirect: message sent from router specifying that it is not the best gateway for the host.

SLAAC

• SLAAC – StateLess Address AutoConfiguration

• Allows a host to automatically configure their own IPv6 Address

• Uses NDP to determine a valid Global IPv6 Address

• Uses EUI-64 method

Dynamic Host Configuration Protocol (DHCP)• Allows a DHCP server to

assign/configure an IP Address to an end device

• Will also configure Subnet Mask, Gateway IP, as well as DNS Servers

• When an end device is configured for DHCP, the DORA begins (IPv4) or SARR begins (IPv6).

DHCP – cont.

• DORA (IPv4) – – Discover – Client sends a broadcast

message to DHCP Server– Offer – Server sends a message to client

with an IP Address Offer– Request – Client formally request IP

Address Offered, and sets Subnet Mask, gateway, DNS and lease time

– Acknowledge – Server Acknowledges client Request and reserves IP.

• Once lease is at half-life, DORA process is repeated.

DHCP – cont.

• SARR– Solicit – Client sends a multicast message to

DHCPv6 Server– Advertise – DHCPv6 Server(s) replies to client

with their IPv6 Address– Request – Client formally request IP Address

Offered, and sets Prefix, DNS and lease time, but not gateway (learned from ICMPv6)

– Reply – Server Acknowledges client Request and reserves IP.

• Once lease is at half-life, SARR process is repeated.

Domain Name Service (DNS)• DNS – Maps a domain name like

google.com to an IP Address• DNS Support for IPv6 has been added• “AAAA” records are used to map a

FQDN like google to an IPv6 Address• “A” Records are used to map FQDN to

an IPv4 Address.

Session 1 Review

• How many bits are in an IPv6 Address?• What method is used by DHCPv6?• What does the double colon “::” mean

in hexadecimal numbering system for IPv6?

• Does ICMPv6 use broadcast or multicast messages?

• How is a default route or default gateway determined?

Session 1 Q&A

• Any Questions???

Break time

15 Minutes

Every Day IPv6 and You

Session 2

Why did IPv6 become Necessary?• We are out of IPv4 Space• ARIN reports only 0.00374 of /8 left

– Only 245 /24s left (62,720 IPs left)• Approximately 42.4% of the world’s

population uses the internet as of Dec 2014, where as only 12.7% used the internet in Dec 2004. (internetworldstats.com)

Where are we at with IPv6 Deployment?• Since World IPv6 Launch day, on June

6th, 2012, many companies including Time Warner Cable and Comcast have committed to launching IPv6.

• Currently most companies are running both IPv4 and IPv6 at the same time.

• Comcast, Charter, Cox and Time Warner Cable

What are the challenges to IPv6 deployment?• End Device support (software and

hardware)– Windows 7 and 8+ Support IPv6– Mac OS X v10.1 and later Support

IPv6• End Device (Wireless Routers)

– Check your vendor’s website to see if IPv6 is supported.

Where are we at with IPv6 Deployment? – cont.• Most cable companies are providing

IPv6 to customers– Network Devices have already been

configured– Network Backbone already supports

IPv6– IPv6 Allocations have already been

received and deployed

What are the challenges… – cont.• Modem Support

– Not all modems have firmware that support IPv6.

– Each cable company has a list of supported IPv6 enabled modems.

• Website Support– Most websites are IPv4 only. Many

bigger sites such as Google, Yahoo, Microsoft all support IPv6.

What are the challenges… - cont.• End User

– Training for Field Techs/CSR/Engineers

– Subscriber training

Is my computer IPv6 Ready?• Here is how you can check:

– Go to www.ipv6-test.com or www.test-ipv6.com

– Go to ipv6test.google.com

IPConfig

• Run cmd• Type ‘ipconfig /all’

– Displays all IP Addresses• Type ‘ipconfig /release’ & ‘ipconfig /renew’

– If you need to refresh the IP with the DHCP Server do a /release & /renew

• Type ‘ipconfig /flushdns’– If you are having problems reaching

some websites, run a /flushdns

Tracert (Traceroute)• Run cmd• Shows latency and hopcount• Each hop is a router interface• Maximum hops on tracert is 30• Type ‘tracert -6 google.com’

– To see if you can reach google or any other domain name.• Type ‘tracert -6 <ipv6 address>’

– If you are unable to resolve any DNS, you can still traceroute using an IP Address

• Type ‘tracert -6 <ipv6 gateway>’– If you are trying to reach your local router’s gateway ip

address• Type ‘tracert -6 <cpe gateway ip>’

– If you are trying to reach your CPE gateway IP Address on the CMTS.

Ping

• Run cmd• Great test for packet loss• Type ‘ping google.com’

– To see if you can reach google or any other domain name

• Type ‘ping -6 –t <ip or domain name>’– To test for packet loss on the internet. –t will

continuously ping until cntr-c is pressed.• Type ‘ping -6 –n <count> <ip or domain name>

– To test for packet loss with a specific amount of packets.

• Type ‘ping -6 –l <size of packet> <ip/domain>– To test for packet loss with a greater packet size.

NSLookup

• Run cmd• Used to query DNS Server and perform DNS

Lookups• Can be used to determine if DNS server is down or

not reachable• Type ‘nslookup google.com’

– Performs a standard lookup• Type ‘nslookup <ip address>’

– Performs a reverse dns lookup to find domain name

• Type ‘nslookup <ip/domain> <server ip>’– Performs a lookup using a different server

Network-tools.com

• Go to www.network-tools.com– Many different network tools– Allows you to ping from outside cable

network– Can check DNS Records– Can also check email spam blacklists