"Network Engineer" Part7 Next-generation Internet

"Network Engineer" Part7 Next-generation Internet

1, in IPV4 and IPv6 mixed network, the protocol translation technology is used for communication between pure IPV4 host and pure IPV6 host .

The need for communication between pure IPV4 hosts and pure IPV6 hosts, due to the different protocol stacks, is naturally required to translate these protocols into translation. The translation of the Protocol involves two aspects, on the one hand the translation of the IPV4 and IPV6 protocol layer, and the other is the translation between IPV4 application and IPV6 protocol stack application.

Translation strategies can correspond to a variety of implementation techniques, in which nat-pt and TRT are mainly used in the network aggregation layer, while the BIA and BIS are mainly for the host terminal.

2 . Transition from IPV4 to IPv6

The problems to be solved in the transition period can be divided into two categories: the first is to solve the problem of communication between IPv6 Islands, and the second is to solve the communication problem between IPv6 Island and IPv4 Ocean.

The current proposed transition technology is summarized in 3 types:

1) tunneling technology . used to resolve the problem of communication between IPV6 nodes through the IPv4 network .

2) Dual protocol stack technology . Enables IPv4 and Pv6 to coexist on the same device and on the same network .

3) translation technology . enables communication between pure IPV4 hosts and pure IPV6 hosts .

3, the so-called mobile IP refers to mobile host through the wireless communication network roaming to maintain the network connection , the key technology to achieve mobile IP is: Mobile host has a home network address and obtain a foreign forwarding address .

Note: Simply put, mobile IP technology is to let the computer in the Internet and LAN without any restrictions on the instant roaming, also known as mobile computer technology.

Professionally speaking, Mobile IP technology is a mobile node (computer/server/network segment, etc.) with fixed network IP address, to realize the roaming function across different network segments, and ensure that network rights based on network IP are not changed during roaming.

The key of mobile IP technology is proxy search, transfer address, login, tunnel.

1) proxy search : Is the compute node used to determine if it is roaming.

2) transfer address : The temporary address that is obtained from the external network agent when the mobile node is moved to the external network.

3) Login : It is a series of authentication, registration and tunneling process when the mobile node reaches the outside network.

4) Tunnel : The two-way data channel established between the home agent and the external agent.

4. There are two special addresses in the IPv6 unicast address, where the address 0:0:0:0:0:0:0:0 represents (25) and the address 0:0:0:0:0:0:0:1 represents (26).
(25)
A. Indeterminate address, cannot be assigned to any node
B. Loopback address, which is sent to itself by this address IPV6 group
C. An indeterminate address, which can be assigned to any node.
D. Loopback address for testing the connectivity of remote nodes
(26)
A. Indeterminate address, cannot be assigned to any node
B. Loopback address, which is sent to itself by this address IPV6 group
C. An indeterminate address, which can be assigned to any node.
D. Loopback address for testing the connectivity of remote nodes

Resolution: 25 Reference Answer: A 26 Reference Answer: B
Detailed answer: IPV6 address has unicast address, anycast address and multicast address three kinds:

  (1)   Unicast (Unicast) address The   unicast address is the identifier for a single network interface . For nodes with multiple interfaces, any one of the unicast addresses can be used as an identifier for that node. However, in order to meet the needs of load balancing, it is stipulated in the rfc 2373 that multiple interfaces in the implementation will be allowed to use the same address as long as the interface looks the same. The unicast address of the IPV6 is an address aggregated with a certain length of format prefix, similar to the CIDR address in IPv4. The following two special addresses are available in the unicast address :   indeterminate address : address 0:0:0:0:0:0:0:0 Called an indeterminate address and cannot be assigned to any node . An indeterminate address can be used when the host is initialized, and the Source Address field in the IPV6 group it sends can use this address before the host gets the address. This address cannot be used as a destination address, nor can it be used on IPv6 road headers.   loopback address : address 0:0:0:0:0:0:0:1 is called a loopback address, and nodes send IPv6 groupings to themselves with this address. This address cannot be assigned to any physical interface .  

(2) anycast (AnyCast) addresses This address represents an identifier for a set of interfaces (which can belong to different nodes) . Packets destined for Anycast addresses are sent to one of the interfaces identified by the address, usually the interface closest to the route . The following limitations exist for IPV6 anycast addresses: • Anycast addresses cannot be used as source addresses, but only as destination addresses . Anycast addresses cannot be assigned to IPV6 hosts and can only be assigned to IPV6 routers .

(3) A multicast (multicast) address multicast address is an identifier for a set of interfaces (typically different nodes) , and the packets destined for the multicast address are routed to all interfaces identified by that address. There is no broadcast address in IPV6, its function has been replaced by the multicast address. In the IPV6 address, any full "0" and All "1" fields are legal unless otherwise excluded. In particular, the prefix can contain a "0" value field, or you can use "0" as the End field. An interface can be assigned to multiple addresses of any type (unicast, anycast, multicast) or address ranges.

5, IPV6 address 33AB:0000:0000:CD30:0000:0000:0000:0000/60 can be expressed as a variety of simple
Write the form, the following wording is correct (58)
A 33AB:0:0:CD30/60 B. 33ab:0:0:cd3/60
C 33AB::CD30/60 D. 33ab::cd3/60
Answer: (+) A

The standard answer is a,0000 compression can only be used once otherwise can not determine the exact number of 0000,C, CD30 left and right of the 0 are omitted to omit the two places of the full 0 is therefore incorrect.

6. IPV6 Link Local address

IPv6 "link-local address" is the result of attaching the host's MAC address after the address prefix 1111 1110 10.

Analytical:

ipv6 involves a concept Link-local address, Chinese is called "link-local address" , which is prefixed with FE80::/64
An example of a link-local address: Fe80::713e:a426:d167:37ab

In fact, this concept is similar to IPv4, when the DHCP allocation fails automatically generated 169.254.xxx.xxx such an address, the source address or destination address contains the link-local address of the message, the router should not forward it. Such messages can only be exchanged in one LAN. The address type of the

1, unicast address
2, multicast address
3, anycast address
. Unicast--unicast:one to one
• Unicast addresses are used for one-off connections
· There are six types of IPV6 unicast addresses:
Unicast address six types:
1-aggregate Global Unicast Address 2XXX:XXXXX/3-3FFF:: FFFF

2001::/16 IPV6 Internet Address

2002::/16 6to4 Transition Address

2-link Local Address FE80::/10 (first 10 digits start with FE80)
3-site Local Address (Private) FEC0::/10
4-unspecified Address 0:0:0:0:0:0:0:0/128 +::/128
5-loopback Address 0:0:0:0:0:0:0:1/128 =: 1/128
6-ipv4 Compatible Address:: 192.168.30.1 =:: c0a8:1e01
Here are some specific instructions for some unicast addresses:
1. Aggregatable Worldwide Unicast address aggregate global unicast
Global routed public IP address assigned by IANA
Currently assigned prefix: 2000::/3 occupies 12.5% of the IPV6 address space
2000:0000:0000:0000:0000:0000:0000:0000--3fff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
This prefix contains a total of 8,192/16 prefixes
prefix currently in use for IPV6 Internet operations: 2001::/16
2002::/16 reserved for nodes that use the 6-to-4 transition mechanism
3FFE::/16 prefix for 6bone testing purposes
2. Local Link Address: link-local
When IPV6 is enabled on a node, each interface of the node at startup automatically generates a link-local address
Its prefix 64 bits are specified by the standard, followed by 64 bits in EUI-64 format to construct
Note: On this link, the next hop seen in the routing table is the link local address of the peer, not the public IP address
Prefix: FE80::/10
Scope: can only be used on local links and cannot be routed across subnets
Why you need link-local--in one interface you can configure many IPV6 addresses, so learning routes can be a lot of the next hop.
As a result, the link local address uniquely identifies a node. The local link sees the next hop as the link local address of the peer.
In the process of network re-addressing, the link local address of the node and router does not change, so it is easy to make a modification without worrying about the network unreachable.
R1 (config-if) #ipv6 address fe80:0:0:0:0123:0456:0789:0abc link-local manually specify link-local addresses
3. Local Site Address: site-local
IPV6 's private network address, just like the private network in IPV4 reserved address
Takes up only 0.1% of the entire IPV6 address space
Prefix:FEC0::/10 Subsequent 54 bits are used for the last 64 bits of the subnet ID for the host ID
Range:can only be used within the site, not on the public Internet use
Example: allocating 10 subnets locally

1, FEC0:0:0:0001::/64

2, FEC0:0:0:0002::/64

3, FEC0:0:0:0003::/64

10, FEC0:0:0:000A::/64

The local site address is designed for devices that never communicate with the global IPV6 Internet, such as printers, intranet servers, network switches, etc.
4. address unspecified not specified
Form:0:0:0:0:0:0:0:0
Indicates that the address is not specified, or that all routes are represented when the default route is written
5. Loopback address Loopack addresses
Form: 0:0:0:0:0:0:0:1
Same as the meaning of 127.0.0.1 address in IPV4, indicates that the node is self-
6, embedded IPV4 address IPV6 address IPV4 Compatible addresses

1, IPV4 compatible IPV6 address --used to establish Automatic Tunneling on the IPV4 network to transmit IPV6 packets.

where the height 96bit is set to 0, followed by the IPV4 address of 32bit

0000:0000:0000:0000:0000:0000:206.123.31.2

0000:0000:0000:0000:0000:0000:ce7b:1f01

because this mechanism is not very good, now it is no longer used, instead of using a better transition mechanism

2. mapping IPV4 IPV6 address --only for local scopes with IPV4 and IPV6 dual stack nodes

The height 80bit is set to 0, after 16bit is set to 1, and then with the IPV4 address

0000:0000:0000:0000:0000:ffff:206.123.31.2

0000:0000:0000:0000:0000:ffff:ce7b:1f01

EUI-64 format: Extended Unique identifier

In IPV6, the stateless auto-configuration mechanism uses the EUI-64 format to automatically configure IPV6 addresses

The so-called stateless autoconfiguration refers to the mechanism that allows nodes to configure their own IPV6 addresses without a DHCP server in the network.

EUI-64 Construction rule-generates an IPV6 address based on the MAC address of the interface plus a fixed prefix

How it works: Automatically expands the 48bit Ethernet MAC address to 64bit, then hangs behind a 64bit prefix, forming a IPV6 address

First, the 48-bit MAC address is separated from the middle, inserting a fixed value Fffe
0050:3ee4:4c00-->0050:3eff:fee4:4c00
Second, the 7th bit reversal, if the original is 0, it becomes 1, if the original is 1, it becomes 0
0050:3eff:fee4:4c00-->0250:3eff:fee4:4c00
Third, add the prefix--fe80::0250:3eff:fee4:4c00 this is a complete IPV6 address
Reason for reversal:
In the MAC address, the 7th bit is 1 for local administration and 0 for global management
In the EUI-64 format, the 7th bit is 1 for the global only, and 0 for the local unique
Multicast address multicast
There are no broadcasts in the IPV6, instead of using multicast.
Prefix: FF00::/8 takes up 0.38% of the IPV6 address space

1111 1111 4bit 4bit
|→ fixed value ←| |→ flag ←| |→ range ←|
A flag bit of 0000 indicates a permanent retention of the multicast address, assigned to various technologies using
A flag bit of 0001 indicates a temporary multicast address that the user can use
The scope segment defines the scope of the multicast address, which is defined as follows:
Binary hexadecimal range type
0001 1 Local Interface Range
0010 2 Local Link range
0011 3 Local Subnet range
0100 4 Local Management scope
0101 5 Local site-wide private network addresses that are similar to multicast
1000 8 Organization Scope
1110 E Global-like multicast public address
Here are some multicast-specific addresses:
Ff02::1 all nodes in the local link range all nodes
Ff02::2 all routers routers in the local link range
Ff02::5 all OSPF routers
Ff02::9 all RIP routers all routers running RIP
Ff02::a All EIGRP routers all routers running EIGRP
Ff05::2 all routers within a site range

Multicast address of the requested node Solicited-node multicast address--Important stuff
A special multicast address that will automatically generate a corresponding requested node multicast address for each unicast and anycast address configured on the interface of the node or router. Attentionlink-local address also generates the multicast addresses of a requested node。
Working range: Valid only on local links
Characteristics:

1. On a local link, the multicast address group of the requested node usually contains only one user
2, as long as you know the IPV6 address of a node, it can calculate the multicast address of its requested node
Function: 1, in IPV6, there is no ARP. ICMP replaces the function of ARP, the multicast address of the requested node is used by the node to obtain the link layer address of the same local link neighbor node
2, used for duplicate address detection Dad, before using stateless autoconfiguration to configure an address as its own IPV6 address, the node takes advantage of Dad
Verify that the address is already in use on its local link.
Prefix: ff02:0000:0000:0000:0000:0001:ffxx:xxxx/104
ff02::1:ffxx:xxxx/104
How to generate: the first 104 bits of the multicast address of the requested node are fixed, and the last 24 bits of the IP address are moved down to fill the back.
Example: IPv6---2001::1234:5678/64
Requested node multicast address---ff02::1:ff34:5678/104
Where FF02::1:FF is a fixed part, a total of 104 bits
Multicast IP address mapping to MAC address:
Mapping rule: The first 16 bits of the multicast MAC address are fixed to 0x3333, and the last 32 bits of the multicast IPV6 address are mapped directly to the last 32 bits of the multicast MAC address.
Example: IPV6 address is--FF12::1234:5678/64
The corresponding multicast MAC address is--3333:1234:5678
0x3333 is a fixed prefix
Example: multicast address for all nodes: ff02::0001
corresponding multicast MAC address: 3333:0000:0001
Anycast addresses anycast Address
Applied in One-to-nearest (one to nearly) mode
Anycast is a single address shared by multiple devices. Assigns IPV6 unicast (unicast) addresses to devices that have the same function. The sender sends a packet with the anycast as the destination address, and when the router receives the packet, It is forwarded to the device closest to it with this address. Unicast addresses are used to assign anycast addresses. For those addresses that are not equipped with anycast, the unicast address is an anycast address when a unicast address is assigned to more than one interface.
For example, mobile features, roaming to other areas, do not have to access the original access point, only need to find the nearest.
Required IPV6 Address:
Once the node is enabled for IPV6, the interface automatically generates the following address
1. Local Link Address
2. Loopback address
3. Multicast address for all nodes Ff02::1
4, if it is a router, there will be ff02::2
5. Multicast address of the requested node
If the interface is equipped with a IPV6 unicast address, it also generates the multicast address of the requested node
"How to write a map in frame relay"
Note: You must write two map, one is the map with the IPV6 address, and one is the map of the link-local address.
Otherwise, there will be no ping through without map mapping.
<ipv6 's Basic command >
R1 (config) #ipv6 unicast-routing to turn on IPV6 routing on the Router
R1 (config-if) #ipv6 enable IPV6 on the interface, a link-local address is automatically generated
R1 (config-if) #ipv6 address 2001::1/64 Specify an IP address that will automatically generate a link-local address when configured
R1 (config-if) #ipv6 address fe80:0:0:0:0123:0456:0789:0abc link-local manually specify link-local addresses
R1 (config-if) #ipv6 address 2001:0410:0:1::/64 eui-64 automatically generates a low 64-bit eui-64 address using IPV6 format
R1 (config-if) #ipv6 unnumbered make this interface use the MAC address of the other interface to generate the source address
R1 (CONFIG-IF) #ipv6 MTU 1500 Configuration Interface MTU value
R1 (config-if) #ipv6th suppress-ra off auto-issued prefix
R2 (CONFIG-RTR) #no Split-horizon Close Horizontal split note that the horizontal split of the IPV6 is closed under the process, not under the interface
Show IPv6 interface E0 displays information about the IPV6 interface, including the IPV6 address

7.

"Network Engineer" Part7 Next-generation Internet