HP 6125G HP 6125G & 6125G/XG Blade Switches Layer 3 - IP Services Conf - Page 94

IPv6 transition technologies, Dual stack, Tunneling, Protocols and standards

Get HP 6125G PDF manuals and user guides View all HP 6125G manuals
Add to My Manuals
Save this manual to your list of manuals

Page 94 highlights

Figure 47 Path MTU discovery process 1. The source host compares its MTU with the packet to be sent, performs necessary fragmentation, and sends the resulting packet to the destination host. 2. If the MTU supported by a forwarding interface is smaller than the packet, the device discards the packet and returns an ICMPv6 error packet containing the interface MTU to the source host. 3. After receiving the ICMPv6 error packet, the source host uses the returned MTU to limit the packet size, performs fragmentation, and sends the resulting packet to the destination host. 4. Step 2 and step 3 are repeated until the destination host receives the packet. In this way, the source host decides the minimum MTU of all links in the path to the destination host. IPv6 transition technologies Before IPv6 dominates the Internet, high-efficient and seamless IPv6 transition technologies are needed to enable communication between IPv4 and IPv6 networks. Several IPv6 transition technologies can be used in different environments and periods, such as dual stack (RFC 2893) and tunneling (RFC 2893). Dual stack Dual stack is the most direct transition approach. A network node that supports both IPv4 and IPv6 is a dual stack node. A dual stack node configured with an IPv4 address and an IPv6 address can forward both IPv4 and IPv6 packets. For an upper layer application that supports both IPv4 and IPv6, either TCP or UDP can be selected at the transport layer, whereas the IPv6 stack is preferred at the network layer. Dual stack is suitable for communication between IPv4 nodes or between IPv6 nodes. It is the basis of all transition technologies. However, it does not solve the IPv4 address depletion issue because each dual stack node must have a globally unique IP address. Tunneling Tunneling is an encapsulation technology that utilizes one network protocol to encapsulate packets of another network protocol and transfer them over the network. For more information about tunneling, see "Configuring tunneling." Protocols and standards Protocols and standards related to IPv6 include: • RFC 1881, IPv6 Address Allocation Management • RFC 1887, An Architecture for IPv6 Unicast Address Allocation • RFC 1981, Path MTU Discovery for IP version 6 • RFC 2375, IPv6 Multicast Address Assignments 86

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
  • 144
  • 145
  • 146
  • 147
  • 148
  • 149
  • 150
  • 151
  • 152
  • 153
  • 154
  • 155
  • 156
  • 157
  • 158
  • 159
  • 160
  • 161
  • 162
  • 163
  • 164
  • 165
86
Figure 47
Path MTU discovery process
1.
The source host compares its MTU with the packet to be sent, performs necessary fragmentation,
and sends the resulting packet to the destination host.
2.
If the MTU supported by a forwarding interface is smaller than the packet, the device discards the
packet and returns an ICMPv6 error packet containing the interface MTU to the source host.
3.
After receiving the ICMPv6 error packet, the source host uses the returned MTU to limit the packet
size, performs fragmentation, and sends the resulting packet to the destination host.
4.
Step 2 and step 3 are repeated until the destination host receives the packet. In this way, the
source host decides the minimum MTU of all links in the path to the destination host.
IPv6 transition technologies
Before IPv6 dominates the Internet, high-efficient and seamless IPv6 transition technologies are needed
to enable communication between IPv4 and IPv6 networks. Several IPv6 transition technologies can be
used in different environments and periods, such as dual stack (RFC 2893) and tunneling (RFC 2893).
Dual stack
Dual stack is the most direct transition approach. A network node that supports both IPv4 and IPv6 is a
dual stack node. A dual stack node configured with an IPv4 address and an IPv6 address can forward
both IPv4 and IPv6 packets. For an upper layer application that supports both IPv4 and IPv6, either TCP
or UDP can be selected at the transport layer, whereas the IPv6 stack is preferred at the network layer.
Dual stack is suitable for communication between IPv4 nodes or between IPv6 nodes. It is the basis of all
transition technologies. However, it does not solve the IPv4 address depletion issue because each dual
stack node must have a globally unique IP address.
Tunneling
Tunneling is an encapsulation technology that utilizes one network protocol to encapsulate packets of
another network protocol and transfer them over the network. For more information about tunneling, see
"
Configuring tunneling
."
Protocols and standards
Protocols and standards related to IPv6 include:
•
RFC 1881,
IPv6 Address Allocation Management
•
RFC 1887,
An Architecture for IPv6 Unicast Address Allocation
•
RFC 1981,
Path MTU Discovery for IP version 6
•
RFC 2375,
IPv6 Multicast Address Assignments