BN535 – MASTER OF ENGINEERING IN INTERNET OF THINGS TECHNOLOGIES
MIOT H6012 – Information Transmission & Management
IPv4 v IPv6 Layer 3 protocols (10% of Total CA)
Overview
The objective of this short assignment is to evaluate the difference between using IPv4 and IPv6 layer 3 protocols on local area networks.
This assignment is based on the MIOT H6012 lecture material and the networking and protocols lab “Lab 3 Configuring IPv6 Static and Default Routes”.
Assignment
Review the two networking configurations outlined in the two networks and protocols labs listed below, the physical layer of both network topologies are identical. At layer 3 one of the one networks is configured to use IPv4 and the other network for IPv6.
• Lab 3 Configuring IPv4 Static and Default Routes
• Lab 3 Configuring IPv6 Static and Default Routes
Explain the difference between both of the network configurations and explore the following topics in your report: –
Visible Differences based on Lab Sheets. Configuring IPv4 Static and Default Routes Configuring IPv6 Static and Default Routes
Addressing (network and a host portion) 32-bit address (8 bit * 4 block =32)
Address Uses decimal numbers separated by dot.
Ipv4 uses subnet mask.
IP address 192.168.0.1
Subnetmask 255.255.255.0 128-bit address (16bit*8 block =128)
Address uses Hexadecimal numbers separated by colon:
Ipv6 uses Ipv6 address/prefix length.
2001:DB8:ACAD:A::/64 eui-64
Routing Requires configuring IP router address for default gateway Automatically done in case of Ipv6 by protocol
Types of addresses IPv4 addresses are: unicast address, multicast address, and broadcast address. IPv6 addresses are: unicast address, multicast address, and anycast address.
Configuration/ localhost address IP addresses and routes must be assigned to configure a newly installed system before it can communicate with others.
IP address range 127.0.0.0 to 127.255.255.255 is reserved for loopback, a Host’s self-address. SLAAC Protocol handles Configuration, so it’s optional. IPv6 can be used with any Ethernet adapter and can be run over the loopback interface.
1. Explain the difference between using DHCP and SLAAC on the local area networks.
DHCP is a protocol required in case of Ipv4 whereas SLAAC protocol is preferred for Ipv6 configuration.
Dynamic Host Configuration Protocol (DHCP) is a client/server protocol that automatically provides an IP address and other related configuration information such as the subnet mask, default gateway and Domain name system (DNS) addresses to Internet Protocol (IP) host.
DHCP is a preferred method of “leasing” Ipv4 addresses to hosts on large networks, reduces the burden on network support/admin staff and virtually eliminates entry errors.
• DHCP is not Routable and not Secure.
• DHCP has nothing that allow clients and servers to verify/identify/authenticate each other.
Clients and servers are vulnerable to deception (one computer pretending to be another) and to attack, where rogue clients can exhaust a DHCP server's IP address pool.
Manual configuration method for Ipv4: figures shown below (8-bit segment addresses written in decimal and separated by dot)
Manual address Configuration for IPv6 addressing: (uses hex codes in addressing and can shorten addresses by using double colon once in place of 0 segments/packets)
Dynamic configuration of addresses in IPv6 using SLAAC and DHCP
IPv6 is a protocol that supports many automatic plug and play functionalities. So, there are several methods to assign IP addresses in IPv6.
Methods of IPv6 address assignment: Stateless and Stateful
Stateful Address Assignment
Like IPv4, IPv6 can use DHCP to state-fully assign IP addresses to any clients or host.
SLAAC
Stateless Address Auto Configuration (SLAAC) Protocol:
SLAAC is simple and faster way to provide an IPv6 address to a client.
• Automatic method by which a device obtains its prefix, prefix length and default gateway from an IPv6 router.
• SLAAC protocol cannot assign a subnet mask, but it can assign individual addresses from a /64 link prefix
• Suitable for applications requiring secure connection without additional mediator in the form of a proxy or a DHCP server or NAT or DHCPv6)
• Depend upon ICMPv6 Router Advertisement (RA) messages
• Suitable for wireless networks and cost effective.
• Allows hot plugging of network devices.
2. Explain why static default routes are added to each router in order to get end to end functionality.
Static Routing: Manual method of adding address routes to the routing table of a router. This is a method for small networks like LAN, but it is not suitable for larger networks.
Consider our source is in network 192.168.1.0/24 (Host1) and our destination is in network 192.168.5.0/24 (Host3). Therefore, source to destination path Router1>>Router2>>Router3.
Router1 has no idea about the destination network. So, we have to add a route. The next hop for Router1 in direction of the destination is Router2’s fa0/0 interface. We can add route using following command:
Router2 also has no idea about the destination network. So, we need to add a route to the next hop in direction of 192.168.5.0/24 that is Router3’s fa0/0 interface. The following command can be used:
Router3 knows the destination network because it is directly connected to it. So a no need to add route.
From the destination to source, which is Router3>>Router2>>Router1:
Router3 does not know the 192.168.1.0/24 network
Router2 also does not know the 192.168.1.0/24 network
Router1 is directly connected to 192.168.1.0/24.
Default Routing: This is the method in which all routers are configured to send all packets to a single router. This is a very useful method for LAN or networks with a single entry and exit point. It is usually used in addition with Static and/or Dynamic routing.
Dynamic Routing: In this method protocols and procedures are used to automatically generate routing information. This is the most common and complex method of routing.
why static-default routes are added?
Default routing can be considered as a special type of static routing. The difference is that a default route is used to send packets sent to any unknown destination or to a single next hop address.
Consider Router1 without any static routes in it. When it receives a packet delivered to 192.168.5.0/24, it will drop it since it does not know about the destination network.
If a default route is added to static route in Router1 with next hop address of Router2, all packets sent to any unknown destination, such as 192.168.5.0/24 will be forwarded to Router2.
When adding a default route, ensure that the next-hop device can route the packet further, or else the next hop device will drop the packet.
When a particular route towards a destination exists in the routing table, the router will use that route and not the default route. The router will use the default route only when a particular route does not exist.
3. Explain the EUI-64 process used by SLAAC, which allows hosts to automatically generate IPv6 addresses.
SLAAC is a Ipv6 Protocol in which a 64-bit prefix is assigned to the host or router and the last 64 bits of its address are acquired by the host or router with help of EUI-64 process. SLAAC uses Neighbor Discovery Protocol.
EUI-64 in IPv6 addressing ensures that the autoconfigured addresses are unique on a global level.
The first part is a job for network administrator to set the prefix for this local network. To be able to communicate, all hosts in this network need to have NETWORK part of the address same.
That second part is EUI-64 autoconfiguration of the address. The EUI-64 is that format used by the host for these addresses in order to ensure that there will not accidentally be two or more equal addresses autoconfigured.
EUI-64 Process
▪ process uses a client's 48-bit Ethernet MAC address, and inserts another 16 bits in the middle of the 46-bit MAC address to create a 64-bit Interface ID
▪ advantage is Ethernet MAC address can be used to determine the Interface – easily tracked
EUI-64 Interface ID is represented in binary and is made up of three parts:
▪ 24-bit OUI from the client MAC address, but the 7th bit
(the Universally/Locally bit) is reversed (0 becomes a 1)
▪ inserted 16-bit value FFFE
▪ 24-bit device identifier from the client MAC address
4. Explain the function of Router Advertisement messages in IPv6.
When a device is connected to network and is up, it sends a Router Solicitation message. Basically asking, “Are there some routers out there?”. If any router available on the same network, that router will reply with a Router Advertisement message.
The router tells the client some information i.e. default gateway (link-local address of the router) and the global unicast prefix (example- 2001:DB8: ACAD:10::/64) via Router advertisement messages.
With these information, the client will create a new global unicast address using the EUI-64 method. Thus, the client has an IP address from the global unicast prefix range of router, and that IP address is valid over the Internet.
Router Advertisement message can contain:
1. SLAAC Only: use the information contained in the RA message.
2. SLAAC and DHCPv6: use the information contained in the RA message and get other information from the DHCPv6 server, stateless DHCPv6 (example: DNS)
3. DHCPv6 only: device should not use the information in the RA, stateful DHCPv6
• Using SLAAC, devices are dependent on the local router's ICMPv6 Router Advertisement (RA) messages to obtain the necessary information. IPv6 routers send ICMPv6 RA messages, every 200 seconds, to all IPv6-connected devices on the network.
• Router Advertisement message is also sent in response to a host sending an ICMPv6 Router Solicitation (RS) message.
ICMPv6 (Internet control message protocol Ipv6) Neighbour Solicitation and Neighbour Advertisement Messages (Replaces ARP IPv4)
Two additional message types:
1. Neighbour Solicitation (NS)
2. Neighbour Advertisement (NA) messages
Used for:
• Address resolution (Replaces Address Resolution Protocol used in IPV4)
• Duplicate Address Detection (DAD)
• Executed on the address to validate that it is unique.
• Applied when a device on the LAN knows the IPv6 unicast address but does not know its Ethernet MAC address of a destination.
5. Give details of how many end hosts each network can accommodate.
This can be explained using Classless Inter-Domain Routing (CIDR) chart:
Subnet Mask in our IPv4 configuration: 255.255.255.0 which means 28 = 256 addresses for hosts.
The size of the prefix, is written in bits, after the / slash. Total 32 bits of IPv4 address space available.
If a network has the address 192.0.2.0/24, the number-24 refers to how many bits are there in the network. Using this, the number of bits left for address space can be calculated.
IPv6 is just like IPv4, but structured and all LAN’s have 64 bits of network prefix as compared to variable length of network prefix in IPv4 networks.
All IPv6 networks can have 18,446,744,073,709,551,616 IPv6 addresses.
Presently, most Internet service providers assign /48 network prefixes to subscriber’s sites (the End Users/hosts networks). This is due to reason that all IPv6 networks have /64 prefixes. A /48 network prefix allocates 65,536 LANs in an End User's site.
6. In relation to the OSI model explain the difference between network switches and routers and how the decisions to forward frames / packets are made by each type of device.
A router is an intermediate device that connects computer networks. Routers are workhorses that transfer packets of data between networks to establish and maintain communication between two nodes in an internet network. Routers operates at Layer 3 (network layer) of the OSI model; a router uses the destination IP address in a data packet to determine where to forward the packet.
A Network switch is used to connect several computers together on a single computer network. A switch is also called switching hub (Network hubs – also called repeaters), bridging hub, or MAC bridge.
Switches use MAC addresses to forward data to the specific destination. A switch is a Layer 2 device, operates at the data link layer; switches use packet switching to receive, process and transmit data.
Differences Router Switch
Layer Network Layer (Layer 3 devices) Data Link Layer. Network switches operate at Layer 2 of the OSI model.
Function Directs data in a network. Passes data between home computers, and between computers and the modem. Allow connections to multiple devices, manage ports, manage VLAN security settings
Data Transmission form Packets Frame (L2 Switch), Frame & Packet (L3 switch)
Ports 2/4/5/8 Switch is multi port Bridge. 24/48 ports
Device Type Networking device Active Device (With Software) & Networking device
Transmission Type At Initial Level Broadcast then Uni-cast & Multicast First broadcast; then unicast & multicast as needed.
Network scope LAN, MAN, WAN LAN
Table Store IP address in Routing table and maintain address at its own. Switches use content accessible memory CAM table which is typically accessed by Application Specific integrated chips.
Transmission Mode Full duplex (communication in both directions at same time) Half/Full duplex
Broadcast Domain In Router, every port has its own Broadcast domain. Switch has one broadcast domain [unless VLAN implemented]
Speed 1-100 Mbps (Wireless); 100 Mbps – 1 Gbps (Wired) 10/100 Mbps, 1 Gbps
Address for transmission
Uses IP address Uses MAC address
Security Provides security measures to protect network Port security
Used for Connecting two or more networks Connecting two or more nodes in the same network (L2) or different network (L3)
Routing Decision Take faster routing decisions
Take more time for complicated routing decisions
NAT
Routers can perform Network Address Translation Switches cannot perform NAT
Faster
In a different network environment (MAN/ WAN), a router is faster than an L3 switch. In a LAN environment, an L3 switch is faster than a router (built-in switching hardware)
Function of Router and switch to forward Packets/Frames:
A router is a more advanced device than a switch. Conventional routers were designed to join multiple area networks (LANs and WANs). Routers serve as intermediate (medium) destinations for network traffic. They receive TCP/IP packets, look inside each packet to identify the source and target IP addresses, then forward these packets as required to verify the data reaches its destination. Routers can perform network address translation (NAT), which allows all devices on a subnetwork (all devices connected) to share the same public IP address. Routers that include built-in firewalls improves the network's security.
A Network switch is used to connect several computers together within one local area network (LAN). Switches are unable to combine multiple networks or sharing an Internet connection. A home network with a switch must assign one computer as the gateway to the Internet, and that device must possess two network adapters for sharing, one for the home LAN and one for the Internet WAN. With a router, all home computers (host) connect to the router identically, and it performs the equivalent gateway functions.
7. Explain they key benefits of using IPv6 over IPv4 for this network.
Key benefits of using IPv6 over IPv4:
1. Larger IP Address space in IPv6 as compared to IPv4.
2. Better end to end connectivity as compared to IPv4.
3. Through SLAAC IPv6 has better auto-configuration method for devices than IPv4.
4. IPv6 has simplified header structures that leads to faster routing than IPv4.
5. IPv6 provides better security for applications and networks than IPv4.
6. Better Quality of service in IPv6.
7. Better multicast and anycast abilities in IPv6
8. IPv6 follows design features from Ipv4, allowing a smooth transition from IPv4
References:
[1] Powell, D. Lecture 4 Networking [online]. Available from: <https://moodle.itb.ie/mod/folder/view.php?id=185000> [accessed 31/10/2018].
Techtarget Network (2017) [online]. Available from: <https://searchnetworking.techtarget.com/definition/DHCP> [accessed 31/10/2018].
Short, P. & McIllece, J. (2018) Dynamic Host Configuration Protocol (DHCP) [online]. Available from: <https://docs.microsoft.com/en-us/windows-server/networking/technologies/dhcp/dhcp-top> [accessed 31/10/2018].
Maggio, A. (2016) DHCPv6 Configuration: SLAAC, Stateless and Stateful [online]. Available from: <https://www.ictshore.com/free-ccna-course/dhcpv6-basics/> [accessed 31/10/2018].
[2] 4-2 Static, Default and Dynamic Routing (a) [online]. Available from: <http://www.freeccnastudyguide.com/study-guides/ccna/ch4/routing/> [accessed 31/10/2018].
[3] Popeskic, V. (2018) IPv6 – SLAAC EUI-64 Address Format [online]. Available from: <https://howdoesinternetwork.com/2013/slaac-ipv6-stateless-address-autoconfiguration> [accessed 31/10/2018].
Powell, D. Lecture 4 Networking [online]. Available from: <https://moodle.itb.ie/mod/folder/view.php?id=185000> [accessed 31/10/2018].
[4] Powell, D. Lecture 4 Networking [online]. Available from: <https://moodle.itb.ie/mod/folder/view.php?id=185000> [accessed 31/10/2018].
Maggio, A. (2016) DHCPv6 Configuration: SLAAC, Stateless and Stateful [online]. Available from: <https://www.ictshore.com/free-ccna-course/dhcpv6-basics/> [accessed 31/10/2018].
[5] Understanding IP Addressing and CIDR Charts (2016) [online]. Available from: <https://www.ripe.net/about-us/press-centre/understanding-ip-addressing> [accessed 31/10/2018].
[6] Router Vs. Switch (b) [online]. Available from: <https://www.diffen.com/difference/Router_vs_Switch> [accessed 31/10/2018].
[7] Top 10 Features that make Ipv6 Better than Ipv4 (c) [online]. Available from: <https://www.ipv6.com/general/top-10-features-that-make-ipv6-greater-than-ipv4/2/> [accessed 31/10/2018].
Report and Deliverables
1. Report should be submitted via Moodle upload deadline.
2. Report should report should be at least 2.5 pages excluding diagrams.
3. Report should contain research elements as outlined above.