LAN upgrade IPv6 is thenext step from IPv4. The demand for an alternative to IPv4 had been anticipatedfor a very long time, as early as 1988 when Vin Cerf said that “we should beworried about this IPv4 exhaustion and should be thinking about how toexpand the available space” (Pickard,2017). Cerf was referring to the fact that IPv4 has a limited numberof IP addresses available, “The long anticipated exhaustion of theInternet Assigned Numbers Authority (IANA) IPv4 global address pool occurred inFebruary of 2011. Since that time, four of the five regional Internetregistries (RIRs) have also exhausted their IPv4 address pools, leaving theAfrican Network Information Centre as the only RIR with a pool of IPv4addresses remaining for general allocation.” The main reason why a move fromIPv4 to IPv6 will occur is due to this fact. Some of the advantages of switching to IPv6 are that it hasway more IP address than we will ever need, it has shorter TCPconnections(Bajpai,2017) and, theoretically, eliminates the need for NAT,reinstating end-to-end connectivity.
(Reddy,2012). The support for IPv6 is alsoincreasing, and increasing quicker in recent years and percentage growth ofIPv4 is slower than IPv6 right now(Pickard,2017) However, there are some drawbacks too. While Nikkhah, Guérin(2015) and Pickard(2017) show that the usage of IPv6 hasbeen increasing recently, it still is in a minority, for example only 3% ofusers were accessing the services of Google using IPv6 in 2014. One possible reason is the costof upgrading infrastructure. The contentavailable in IPv6 is fairly limited, users tend to stick to defaultconfiguration of host machines, some of which tend to favour IPv4 and IPv6 bydefault, and data shows that IPv6performance is roughly similar or in some cases worse than IPv4(Pickard,2017)(Bajpai,2017)(Nikkhah, Guérin, 2015). When all these factors are combined together thecost of upgrading infrastructure for ISP and companies may seem a unnecessaryexpense.
Another drawback is the securityissues that relate to IPv6. As Nicolls (2016) points out that investigators arefamiliar with IPv4 but not with IPv6, so it will be harder for criminals to betracked down, not to mention the cost of training investigators to be familiar withIPv6. Another issue that Nicolls raises is that many firewalls are not configuredto filter IPv6 packets, instead the only work on IPv4 packets, so systems maybe exposed to IPv6 attacks. To summarise, a switch to IPv6 is necessary due to the limited IPaddresses available and all studies agree that use of IPv6 is increasing, butprogress is being stalled by the low demand, and high expense, for upgradingthe infrastructure and the training and solutions the security issues that theswitch requires. To fully switch to IPv6, theorganisation should make an inventory of equipment that does not support IPv6and decide whether to replace or discard them. Another factor to consider isthat as IPv6 technology matures that cost of infrastructure will decrease, so adecision must be made to decide whether to delay, and upgrade for a larger userbase, or upgrade now(Nikkhah, Guérin, 2015). As the IPv6 internet amount is not big at thispoint, so the company must decide whether to go ahead with the full switch oruse dual-stack, where hosts can receive both IPv4 and IPv6 addresses.
Thecompany could also consider using tunnelled IPv6 connections, that let the IPv4machines connect to IPv6 internet, the IPv6 packets are packaged into IPv4packets by customer’s router and are unpackaged by a tunnel; broker that canthen connect to IPv6 address (Nicolls,2016). VLANVirtual local area network(VLAN)is essentially treated like a subnet of its own. The host on the same VLAN cansend packets to each other but can not communicate outside their VLAN, forinter VLAN communication a router is required(Pal, G P, Pal S,2013) (Singh, A k, Singh S,2012). In a LAN, data is transmitted toall hosts, if two individual were to send data simultaneously a collision couldcause all data transmitted to be lost, and the original data would have to besend again. Furthermore, in a LAN all parts must be in the same physicallocation, which can become a problem in large LANs and will lead to busytraffic on the network. (Mohammed F.
Alsharekh,2016) (Alimi, I A, Mufutau, I A,2015).For VLAN the nodes do notneed to be in the same physical location but instead be grouped by some othermeans. VLANs can also be used to divide a single physical network into multiplenetworks(Singh, A k, Singh S,2012). LAN has a fundamental securityissue. While it may reduce operational cost ,minimised downtime, and share informationreliably over the network, the security issue that remains is that sensitiveinformation can not be segregated to only reach certain hosts, while it can bedone by physically separating the network, but it is not cost effective and maybecome difficult to manage as network grows in size, the solution to thisproblem is VLAN. (Alimi, I A, Mufutau, I A,2015) VLAN is switched network that isseparated logically based on such as workgroup or application requirement.
As all parts of asingle VLAN do not have to be in a single physical location the networkadministrators can manage the network without significant changes to infrastructurerequired. (Alimi, I A, Mufutau, I A,2015)VLANS can be either static ordynamic. Static VLANs have each port manually assigned to the VLAN, which ismore secure but it has to be changed if the host is moved physically.
Thealternative is dynamic VLANs, in which the port is assigned based on MAC address,protocols and applications. (Pal, G P,Pal S,2013)