Information Technology Reference
In-Depth Information
Ta b l e 9 -1 1
IPv6 Deployment Models
Description
IPv6 Deployment
Model
All routers and hosts run IPv6 and IPv4.
Dual-stack model
Uses ISATAP or manually configured tunnels to allow dual-stack
clients to connect to dual-stack servers over a IPv4 core.
Hybrid model
Uses ISATAP and manually configured tunnels to a service module.
Service block model
This section provides a summary comparison of IPv6 to IPv4. Become knowledgeable
about the characteristics summarized in Table 9-12. The use of 128 bits over 32 bits is an
obvious change. The upper-layer protocol is identified with the Next Header field in IPv6,
which was the Protocol Type field used in IPv4. ARP is replaced by IPv6 ND.
Ta b l e 9 -1 2
IPv6 and IPv4 Characteristics
Key
To p i c
Characteristic
IPv6
IPv4
Address length
128 bits
32 bits
Address repre-
sentation
Hexadecimal
Dotted-decimal
Header length
Fixed (40 bytes)
Va r i a ble
Upper-layer
protocols
Next header field
Protocol Type field
Link address
resolution
ND
ARP
Address config-
uration
Stateless autoconfiguration or stateful
DHCP
Stateful DHCP
DNS (name-to-
address
resolution)
AAAA records
A records
Interior routing
protocols
EIGRPv6, OSPFv3, RIPng, IS-IS for
IPv6
EIGRP, OSPFv2, RIPv2, IS-IS
Classification
and marking
Traffic Clas s and Flow L abel fields,
differentiated services code point
(DSCP)
IP Precedence bits, Type of
Service field, DSCP
Private
addresses
Unique-local addresses
RFC 1918 private address space
