Layer 3 Forward and ARP Configuration
Chapter 1 Layer 3 Management Configuration
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1-2
1.2 IP Configuration
1.2.1 Introduction to IPv4, IPv6
IPv4 is the current version of global universal Internet protocol. The practice has
proved that IPv4 is simple, flexible, open, stable, strong and easy to implement while
collaborating well with various protocols of upper and lower layers. Although IPv4 almost
has not been changed since it was established in 1980’s, it has kept growing to the current
global scale with the promotion of Internet. However, as Internet infrastructure and
Internet application services continue boosting, IPv4 has shown its deficiency when facing
the present scale and complexity of Internet.
IPv6 refers to the sixth version of Internet protocol which is the next generation
Internet protocol designed by IETF to replace the current Internet protocol version 4 (IPv4).
IPv6 was specially developed to make up the shortages of IPv4 addresses so that Internet
can develop further.
The most important problem IPv6 has solved is to add the amount of IP addresses.
IPv4 addresses have nearly run out, whereas the amount of Internet users has been
increasing in geometric series. With the greatly and continuously boosting of Internet
services and application devices (Home and Small Office Network, IP phone and Wireless
Service Information Terminal which make use of Internet,) which require IP addresses, the
supply of IP addresses turns out to be more and more tense. People have been working
on the problem of shortage of IPv4 addresses for a long time by introducing various
technologies to prolong the lifespan of existing IPv4 infrastructure, including Network
Address Translation(NAT for short), and Classless Inter-Domain Routing(CIDR for short),
etc.
Although the combination of CIDR, NAT and private addressing has temporarily
mitigated the problem of IPv4 address space shortage, NAT technology has disrupted the
end-to-end model which is the original intention of IP design by making it necessary for
router devices that serve as network intermediate nodes to maintain every connection
status which increases network delay greatly and decreases network performance.
Moreover, the translation of network data packet addresses baffles the end-to-end
network security check, IPSec authentication header is such an example.
Therefore, in order to solve all kinds of problems existing in IPv4 comprehensively,
the next generation Internet Protocol IPv6 designed by IETF has become the only feasible
no
description
The no command will cancel the description information
of VLAN interface.
