ISDN

1
Chapter 7

• Lecture 2

2
ISDN

• Integrated Services Digital Network
• PRI (Primary)
• max. bandwidth 1.544 Mbps for PRI (Primary Rate
  Interface)
• 23 B channels _at_ 64kbps AND
• 1 D channel _at_ 64 kbps
• B (bearer) channels are voice/data channels
• D (delta) channel for signaling
• Transmission carrier T1 (leased line)

3
Packet Switched Services

• X.25 (Connection-oriented)
• Older WAN technology developed in 1970s
• Reliable--X.25 has been extensively debugged and
  is now very stable--literally no errors in modern
  X.25 networks
• Store Forward--Since X.25 stores the whole
  frame to error check it before forwarding it on
  to the destination
• Slow max. transfer speed 56kbps

4
Packet Switched Services

• Frame Relay (Connectionless)
• More efficient and much faster than X.25
• Data rates up to 44.736Mbps
• Forwards LAN IP and IPX packets through a WAN
• Low cost
• Uses modems, ISDN, T1 and T3 for transmission.

5
Cell Switched Services

• Asynchronous Transfer Mode (ATM)
• Max bandwidth 622 Mbps
• Transports data, video, and voice
• High Cost
• Uses fixed length packets (53 bytes)
• Key Benefits
• One network for all traffic--voice, data, video
• Very flexible and scalable
• Simplifies network management

6
ATM and Frame Relay Circuits

• SVC switched virtual circuits
• Only for the duration of the transmission or
  session
• PVC permanent virtual circuits
• Established connection between two devices

7
FDDI

• Fiber Distributed Data Interface
• Uses token passing
• Dual ring topology
• Multi or single mode fiber cable
• Max transmission speed 100 Mbps
• Max transmission length 2 km
• Used in network backbones

8
Beaconing

• FDDI fault detection
• Sends signal (beacon) to upstream neighbor stops
  when the neighbor sends back a response.
• The station without a response is where the fault
  is.

9
FDDI Advantages

• No EMI
• Secure
• Long cable (2 km)
• Fault tolerant (dual ring)
• Beaconing (built-in error detection)
• Fast

10
FDDI Disadvantages

• Expensive
• Requires trained professionals for setup and
  management

11
TCP/UDP Ports

• 21 FTP
• 23 Telnet
• 25 SMTP
• 53 DNS
• 69 TFTP

• 80 HTTP
• 110 POP3
• 143 IMAP
• 161 SNMP
• 443 - HTTPS

12
TCP/IP Ports

• 65,535 Ports
• 0 1023 well-known ports
• 1024 49,151 registered ports
• 49,152 65,535 - unassigned
• http//www.iana.org/assignments/port-numbers