PLANET XGS3-24042 - Manual (Page 194)

22-31
Global Mode
ip vrf <vrf-name>
no ip vrf <vrf-name>
Create VRF instance; VRF instance is not
created by default.
VRF Mode
rd <ASN:nn_or_IP-address:nn>
Configure RD of VRF instance. RD is not
created by default.
route-target {import | export | both}
<rt-value>
no route-target {import | export | both}
<rt-value>
Configure RT of VRF instance
Interface Mode
ip vrf forwarding <vrf-name>
no ip vrf forwarding <vrf-name>
Configure the relation between VRF
instance and the interface.
ip address <ip-address> <mask>
no ip address <ip-address> <mask>
Configure the private IP address of direct
link interface.
22.2 IP Configuration
22.2.1 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