IPv6 interface identifier

The second part of an IPv6 unicast or anycast address is typically a 64-bit interface identifier used to identify a host’s network interface. A 64-bit interface ID is created by inserting the hex value of FFFE in the middle of the MAC address of the network card. Also, the 7th Bit in the first byte is […]

IPv6 address prefixes

Here is a summary of the most common address prefixes in IPv6: Prerequisites for 200-301 200-301 is a single exam, consisting of about 120 questions. It covers a wide range of topics, such as routing and switching, security, wireless networking, and even some programming concepts. As with other Cisco certifications, you can take it at […]

IPv6 multicast addresses

Multicast addresses in IPv6 are similar to multicast addresses in IPv4. They are used to communicate with dynamic groupings of hosts, for example all routers on the link (one-to-many distribution).Here is a graphical representation of the IPv6 multicast packet:IPv6 multicast addresses start with FF00::/8. After the first 8 bits there are 4 bits which represent the […]

Differences between IPv4 and IPv6

The following table summarizes the major differences between IPv4 and IPv6: FeatureIPv4IPv6Address length32 bits128 bitsAddress representation4 decimal numbers from 0-255 separated by periods8 groups of  4 hexadecimal digits separated by colonsAddress typesunicast, multicast, broadcastunicast, multicast, anycastPacket header20 bytes long40 bytes long, but simpler than IPv4 headerConfigurationmanual, DHCPmanual, DHCP, auto-configurationIPSec supportoptionalbuilt-in  Prerequisites for 200-301 200-301 Read more […]


RIPng is an extension of RIP developed for support of IPv6. Here are some of its features:just like RIP for IPv4, it uses hop count as the metricsends updates every 30 secondsRIPng messages use the UDP port 521 and the multicast address of FF02::9 The configuration of RIPng is requires at least two steps:1. enable RIPng […]

IPv6 link-local addresses

Link-local IPv6 addresses have a smaller scope as to how far they can travel: only within a network segment that a host is connected to. Routers will not forward packets destined to a link-local address to other links. A link-local IPv6 address must be assigned to every network interface on which the IPv6 protocol is […]

IPv6 unique local addresses

Unique local IPv6 addresses have the similar function as IPv4 private addresses. They are not allocated by an address registry and are not meant to be routed outside their domain. Unique local IPv6 addresses begin with FD00::/8.A unique local IPv6 address is constructed by appending a randomly generated 40-bit hexadecimal string to the FD00::/8 prefix. […]

IPv6 global unicast addresses

IPv6 global addresses are similar to IPv4 public addresses. As the name implies, they are routable on the internet. Currently IANA has assigned only 2000::/3 addresses to the global pool.A global IPv6 address consists of two parts:subnet ID – 64 bits long. Contains the site prefix (obtained from a Regional Internet Registry) and the subnet […]

How to configure IPv6

Cisco routers do not have IPv6 routing enabled by default. To configure IPv6 on a Cisco routers, you need to do two things:enable IPv6 routing on a Cisco router using the ipv6 unicast-routing global configuration command. This command globally enables IPv6 and must be the first command executed on the router.configure the IPv6 global unicast […]

IPv6 unicast addresses

Unicast addresses represent a single interface. Packets addressed to a unicast address will be delivered to a specific network interface.There are three types of IPv6 unicast addresses:global unicast – similar to IPv4 public IP addresses. These addresses are assigned by the IANA and used on public networks. They have a prefix of 2000::/3, (all the […]

Types of IPv6 addresses

Three categories of IPv6 addresses exist:Unicast – represents a single interface. Packets addressed to a unicast address are delivered to a single interface.Anycast – identifies one or more interfaces. For example, servers that support the same function can use the same unicast IP address. Packets sent to that IP address are forwarded to the nearest server. […]

IPv6 routing protocols

Like IPv4, IPv6 also supports routing protocols that enable routers to exchange information about connected networks. IPv6 routing protocols can be internal (RIPng, EIGRP for IPv6…) and external (BGP).As with IPv4, IPv6 routing protocols can be distance vector and link-state. An example of a distance vector protocol is RIPng with hop count as the metric. […]

IPv6 transition options

IPv4 and IPv6 networks are not interoperable and the number of devices that use IPv4 number is still large. Some of these devices do not support IPv6 at all, so the migration process is necessary since IPv4 and IPv6 will likely coexist for some time.Many transition mechanisms have been proposes.1. IPv4/IPv6 Dual Stacks – each device […]

IPv6 address format

Unlike IPv4, which uses a dotted-decimal format with each byte ranges from 0 to 255, IPv6 uses eight groups of four hexadecimal digits separated by colons. For example, this is a valid IPv6 address:2340:0023:AABA:0A01:0055:5054:9ABC:ABB0If you don’t know how to convert hexadecimal number to binary, here is a table that will help you do the conversion:IPv6 […]