Download IPv6

IPv6 Introduction
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What is IPv6
Purpose of IPv6 (Why we need it)
IPv6 Addressing Architecture
IPv6 Header
ICMP v6
Neighbor Discovery (ND)
Reference Site
What is IPv6
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IP version 6 (Now is IP version 4)
IPng (IP The Next Generation)
RFC791
IPv4 header  IPv6 header
IPv4 structure  IPv6 structure
Plug and Play
IPv6 address allocation in Asia
資料來源：http://www.ipv6.org.tw/
IPv6 subnets in Taiwan
資料來源：http://www.ipv6.org.tw/
Purpose of IPv6
• IPv4 address bottleneck
• CIDR (Classless Inter-Domain Routing)
• NAT (Network Address Translation)
• 3G and IA (Information Appliance)
• Network Security
• IPsec (IP security)
• Wireless Mobile Issue
• Triangle Issue
Purpose of IPv6 (cont.)
• Running out of address in IPv4
– 32-bit vs. 128-bit
– 75% IP addresses in America
– 3G & IA production
• Multicast function is not useful
• Checksum in 2 Layers
• CIDR is the default usage (without
netmask)
Purpose of IPv6 (cont.)
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Simply the complex Header
Reduce router’s loading
Extension Header
More Security with IPsec
QoS (Quality of Service)
Auto-Configuration
– Statefull
– Stateless
(DHCPv6)
(RS,RA)
IPv6 Feature (cont.)
Neighbor Cache
Routing Table
Destination Cache
Prefix List
ARP Table
Default Router List
IPv4
IPv6
IPv6 Addressing Architecture
• IPv6 Address Rule
• Unicast Address
(RFC2374)
– Link local address
– Site local address
– Global address
• Anycast Address
• Multicast Address
(RFC2526)
(RFC2375)
No Broadcast Here!!!!!!
IPv6 Address Rule
• The preferred form is x:x:x:x:x:x:x:x
• X is 16 bit value
• Long strings of zero bits
• 0:0:0:0:0:0:0:1
 ::1
• “前導0” could be skipped
• FFEE:BBBB:00A0:0:0:0:0:1  FFEE:BBBB:A0::1
• The "::" can only appear once in an
address
Unicast Address-Link local
• Link local address
– Used on a single link
– Prefix is 1111 1110 10
– FE80:
• Usage Timing
– Automatic Address Configuration
– Neighbor Discovery
Unicast Address-Site local
• Site local address
– Used on a single site
– Prefix is 1111 1110 11
– FEC0:
Unicast Address-Global
• Global address
– Unique in Internet
– Prefix is 001
Anycast Address
• When a unicast address is assigned to more
than one interface, thus turning it into an anycast
address, the nodes to which the address is
assigned must be explicitly configured to know
that it is an anycast address.
Anycast Usage
R1
R2
A
B
Lower Cost
R3
Anycast Area
Multicast Address
• flags
000T (focus on T value)
– 0 permanently-assigned (well-known address)
– 1 non-permanently-assigned (transient)
• scope
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1：node-local scope
2：link-local scope
5：site-local scope
8：organization-local scope
Others：reserved
Ex：ff02::1
 (link-local) all nodes multicast address
Interface ID
• Created from MAC address
• EUI-64 Address
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Example for link-local:
MAC addr: 00-01-23-AA-BB-CC
EUI-64:
00-01-23 AA-BB-CC
00-01-23 FF-FE AA-BB-CC
00-01-23 -FF-FE-AA-BB-CC
FE80::1:23FF:FEAA:BBCC/64 <- link-local addr.
IPv6-IPv4 comparison
IPv4
IPv6
• Unspecified Host
• Unspecified Host
– 0.0.0.0
• Loopback
– 127.X.X.X
• Broadcast
– 192.168.0.255
• Netmask
– 255.255.255.0
– 0:0:0:0:0:0:0:0 (::)
• Loopback
– ::1
• Multicast
– FF02::1
• Netmask
– Prefix Number
IPv6 Header
IPv4 Header
IPv6 Extension Headers
Routing Header
Routing Header
• Created only when use PATH MTU
function
• PATH MTU：Trying to find out the biggest
MTU size. (RFC 1981)
Fragment Header
Fragment Procedure
All Data
ICMP v6
• Internet Control Message Protocol
• RFC 2463
ICMP sample
A Ping B
A
B
ICMP v4 vs. ICMP v6
• ICMP v4
– echo message
• Type 8
– reply message
• Type 0
– code 0
• ICMP v6
– echo request
message
• Type 128
– echo reply
message
• Type 129
– Code 0
Neighbor Discovery (ND)
• RFC2461
• Corresponds to a combination of IPv4
– ARP
– ICMP Router Discovery
– ICMP Redirect
Neighbor Discovery
• 5 messages
– Neighbor Solicitation (NS)
– Neighbor Advertisement (NA)
– Router Solicitation (RS)
– Router Advertisement (RA)
– Redirect
• All these messages should fill 255 in hop
limit field
• Link Layer address
RS (Type 134)
RA (Type 133)
Regular RA (Type 133)
Use multicast to send its prefix to link-local scope all-nodes
NS (Type 135)
NA (Type 136)
Reference Site
• www.ipv6.org.tw
• www.ietf.org