FOUNDATIONAL BACKGROUND ON SECURITY AND DEPENDABILITY TECHNIQUES

• With developments in IT over the years.
• Global society depends on IT infrastructures
• Infrastructural failures, cyber-attacks, cyberwars are future realities that can affect global society
• Securing and ensuring reliability of IT environment is a growing challenge and is a critical need

Information Assurance

• Integrity
• Information and security should be reliable
• Data should also be reliable; truthfulness in everything given to a user
• Availability
• Information should always be available at all times
• Authentication
• There should always be verification of the user getting information
• User must be identified and authorized before accesing info in network
• Confindentiality
• Confindentiality or privacy is very important
• Information should only be shown if owner permits it
• If not there'll be issues on data privacy

Network Capabilities

• Network Survivability
• The capability of network where traffic can be carried immediately after a failure

Techniques to improve a network's survivability

• Prevention
• Or avoidance techniques
• Focus on improving component and system reliability
• Reduce incident faults
• Contributes to survivability of network
• Making number of surviving components larger
• Network design
• Placing enough variety and capacity in network topology
• Survivable network design techniques try to mitigate effects of system-level failure
• Example is multihoming nodes
• By making each node two or more connected a single link failure cannot separate node from the network

• Resilience
• Ability of network to provide desired service even when challenged by attacks, large-scale disaster, other failures.

Multihoming

• Multihoming is a mechanism used to configure one computer with more than one network interface
• With multiple IP addresses; provides enhanced and reliable internet connectivity
• Multihoming computer is known as the host; directly or indirectly connected to more than one network

Benefits of Multihoming

• Multiple real time connections, system failure less likely than with single connection
• Users work together through multiple entrances; in failure one door closes, other door continue working
• Web management, multihoming helps load balancing, allows network work with lowest interruption
• System continues doring disaster and recovery

Two Main Types of Multihoming

1. IPv4 Multihoming

IPv4 address in dotted-decimal notation

172

16

254

1

↓

↓

↓

↓

10101100

00010000

11111110

00000001

8 bits

32 bits (4 bytes)

• Internet Protocol Version 4 (IPv4) is the fourth revision of Internet Protocol
• Commonly used protocol in data communication over different networks
• It is a connectionless protocol
• Uses in packet-switched layer networks such as Ethernet
• IPv4 is based on the best-effort model
• Multihomed public IP address must be configured with two or more Internet Service Provider (ISP) connections
• Any link or route fails, network traffic is automatically rerouted
• IPV4's major downside is it's central connection point for two ISPs, when it fails, entire network fails
• Border Gateway Protocol (BGP) is used for multihoming purposes
2. IPv6 Multihoming

IPv6 address

128 bits (16 bytes)

0123

4567

89ab

cdef

0123

4567

89ab

cdef

Hexadecimal
notation

↗ Most significant position

Quartet

↖ Hexadecimal position

↓

↗ Bit

0000 0001 0010 0011 Binary
notation
• Internet Protocol Version 6 is an Internet Protocol (IP) used for carrying data in packets from a source to a desination over various networks
• IPv6 is the enhanced version of IPv4
• Can support very large numbers of nodes
• Also known as Internet Protocol Next Generation (IPng)
• Developed in hexadecimal format, contains 8 octets to provide large scalability
• IPv6 deals with address broadcasting without containing broadcast addresses in any class
• Traffic management
• Procedures seek to quickly detect a failure or degraded QoS and direct the network load
• typical example is the use of preconfigured backup label–switched paths in multiprotocol label switched (MPLS)
• Disruption Tolerance or Disruption Tolerant Networking
• DTN a networking architecture that is designed to provide communications in the most unstable and stressed environments
• For networks that frequent and long lasting disruptions and high bit error rates that could harshly damage normal communications.
• DTN works using different kind of methodology than TCP/IP or Transmission Control
• DTN is based on a new experimental protocol called the Bundle Protocol (RFC 5050).
• BP operates as an overlay protocol that links together multiple subnets (such as Ethernet-based LANs) into a single network