IPv6 … A Simplified
Explanation
Presented by
Bryan Crisler
Senior Network Engineer
Time 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
– 0000:0000:0000:0000:0000:0000:0000:00
00
– 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:0000:0000:0000:00
00 -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: Comparison
IPv4
IPv6
32-bit
128-bit
Number of Addresses
4,294,967,296
340,282,366,920,938,4
63,463,374,607,431,76
8,211,456
Network Address
X
X
Broadcast Address
X
N/A
Link-Local Range
169.254.0.0/16
FE80::/10
Multicast Range
224.0.0.0 –
239.255.255.255
FF00::/8
Dynamic Addressing
DHCP
SLAAC or DHCPv6
Security
Optional
IPSec built-in, optional
Header Length
Variable
Fixed
Address
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, DNS
ICMPv6, 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.testipv6.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