IPv6 Address

RIP is a #classful #Distance Vector Routing Protocol that use hop count as metric to find out the routing path. The underlying #algorithm used is the Bellman-Ford Algorithm. If the metric of route is larger than 15, RIP will count it as unreachable. Routing updates are done via broadcast IP address. It can only run on IPv4 networks, in order to run IPv6 one needs to deploy RIPng (RIP next generation) instead. There is a classless implementation of RIP: RIP version 2 (RIPv2)#.

The process of forwarding the packet from its received port to the outgoing port is called switching. Despite the naming, Router will immediately drop the packet when it can’t figure the destination in its routing table maintained by itself. Otherwise, it will simply modify the destination Media Access Control Address (MAC) (the next-hop, can be another Router or the final destination) in the packet without touching the IP Address which defines the final destination. Though the primary forwarding decision will be based on the Routing Table# or routing information, assuming there is a mapping of logical address to its interface or port. If there is no path defined in the routing table to where the packet should be forwarded to, Router will redirect it to a default route if set (usually 0.0.0.0 in IPv4 Address and ::/0 in IPv6 Address), or simply discards it and sends Internet Control Message Protocol (ICMP)# Unreachable message to the source. Additionally, we can divide a physical interface into at most 65,535 logical interfaces using the command interface {interface-name} {interface}.{subinterface}. This is particularly useful in Virtual LAN (VLAN) routing.

In OSPFv3, it will advertise not only the IPv6# link-local address but also the global address.

OSPF is a #Layer 3 #classless #Link-State Routing Protocol developed by Internet Engineering Task Force (IETF)# where its metric is an arbitrary value called cost (defined by RFC 2328). In Cisco, the cost calculated using bandwidth. It is secure, scalable and provides fast Convergence#. It supports both IPv4 and IPv6. The implementation of OSPF varies from vendor to vendor.

IP is the underlying protocol used by World Wide Web (WWW) to connect other computers over the network which is included in the #Internet Protocol Suite (TCP/IP). It is considered as #Network Layer protocol according to #Open Systems Interconnection (OSI) Model. Currently, it has two versions: IPv4# and IPv6#.

IS-IS is a #classless #Link-State Routing Protocol which has wide adoption by Internet Service Provider (ISP)#. It is a rather harden protocol to used as the attacker couldn’t break into a network routing with IS-IS using other Routing Protocol. It is available for both IPv4# and IPv6#.

Although there are technologies such as Network Address Translation (NAT)# and Port Address Translation (PAT)# trying to overcome the limitation of IPv4 Address, the possibility of running out of public address becomes greater as Regional Internet Registry (RIR)# starts facing the trouble of exhausted IPv4 Addresses in the 2010s due to the introduction of personal digital assistant (PDA), cellphones, Internet of Things (IoT) etc. The alternative is to switch over to IPv6 Address#.

IPsec is an #Network Layer security framework for secure communications over Internet Protocol (IP)# network. This means it could protect every application or Protocol#, including those that are security-ignorant (doesn’t design around security), running on top of IP (IPv4 or IPv6#, however, both of them are not compatible to each other). It is common having it to have secure access over the Internet, extranet and intranet connectivity with partners or just to enhance the security especially in electronic commerce. It provides Authentication#, Confidentiality#, and key management (secure key exchanges) services.

The security architecture of IPsec is defined by RFC 4301 which includes the need of tunnel/transport mode and SA with database implementation. Further standardisation are done in RFC 2401, RFC 2402, RFC 2406, and RFC 2408, which makes IPsec mandatory in #IPv6 Address and optional in IPv4 Address (which needs additional application). IPsec’s implementation must support four cases of Security Association (SA)#:

e2e occurs between the original source and the final destination, that is the encryption is happened in either Application Layer#, Presentation Layer#, Transport Layer# or Network Layer#. This implies that they have the shared keys. e2e only concerns about the encryption of the user data. If user’s privacy and security is desirable, then e2e is preferred. However, due to the translation limit when jumping between different network technology such as IPv4# and IPv6#, the data sent must be decrypted and then be transformed to an understandable form. This could be a huge compromise.

BGPv4 is a widely adopted #Exterior Gateway Protocols (EGP) by Internet Service Provider (ISP) which is available for both IPv4 Address and IPv6 Address)