U2.4 LANs, MANs, WANs

U2.4 LANs, MANs, WANs

1. LAN

   • security issues
     • failures on backbone
     • failures where backbone connects with each workgroup
       • provides a point of access from a workgroup to the backbone
       • provides a point of access to all data associated with a workgroup
     • information flow control
     • network management
       • failure to manage leads to
         • network operation disruption
         • increased effort to identify problems
         • longer time to problem resolution
   • threats to CIA
     • eavesdropping
     • data corruption
     • backbone loss
   • protection measures
     • used dedicated switchers per workgroup
     • each switch should restrict the flow of data to the backbone
     • use firewalls where additional separation needed
     • use encryption

2. MAN

   • metropolitan area network
     • a separate backbone connects the backbones of multiple networks in different buildings
   • campus network
   • additional security issues
     • data travels outside the building
     • non-physical links may need to be considered
       • laser
       • infrared
       • microwave
     • complexity
   • protection measure
     • network information center needed to manage and monitor health

3. WAN

   • threats
     • general
       • sensitive items more widely transmitted
       • network likely to be switched with multiple routes
       • more unmanned equipment rooms managed remotely
       • possibility for unauthorized access to network links higher
     • impact of errors from configuration much larger
     • variation per medium
       • fibre
         • minimal external radiation
         • special tapping equipment needed
         • taps tend to cause service disruption
       • satellite, radio, microwave
         • extensive external radiation
         • easily available (but special) tapping equipment needed
         • tapping does not disrupt service
         • carrier MIGHT provide some encryption
   • possible security measures
     • partition networks, physical separation
     • partition networks, logical separation
       • achieved with permanent virtual circuits or crypto
     • data confidentiality
       • network partitioning
       • link encryption (layer 2)
       • end-to-end encryption (layer 4)
     • link encryption
       • for individual links betwee two points
     • Conditions of Connection (COC)
       • user must agree before getting access to network

4. Internet

   • security issues
     • route of sensitive data not guaranteed
     • availability of internet not guaranteed
     • denail of service real
     • any host can probe any other host