1. Network Architecture Johan Lukkien
Computer Networks 2002/2003
Network Architecture
Johan Lukkien
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

2. Network Architecture Elements Nodes (hosts)
Interconnect (wires + repeaters/hubs)
Topology
Software
stack
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

3. Network architecture design
Generality: do not limit the scope unnecessarily
avoid use-specific designs
Robustness
node & link failure: local impact
limit effect of malfunctioning
e.g. domains
stability: left to itself the system converges to a defined & useful state
e.g. no global reboots
removing malfunctioning component is enough
fault resilience
detection: auto-diagnose
Byzantine behavior
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

4. Network architecture design
Scalability
design works for small and large networks
e.g., performance, exploitation of locality
extensions possible
Configurability
automatic (cf. stability), local configuration
tweakable: optimizable for certain conditions
Determinism
Migration & evolution
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

5. Architecture and distance
home networks
wireless networks
long-distance wire-less
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

6. Local area networks Typically, based on shared medium
broadcasting at layer 1 or layer 2
Relatively small distance (few kilometers, at most)
Simple topologies
10Base2 ethernet
Star: 10(0)BaseT
Token ring
ownership (token) passed around
owner puts packets on an removes them from the ring
owner puts token on the ring again
medium can be shared as well
as point-2-point
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

7. Local Area Networks High total bandwidth (the shared medium is fast)
Limited number of nodes
Low delay and error rate
Broadcast facility supported
i.e., part of the layer 2 service
All nodes equal
though some a bit more than others....
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

8. Standardizing LANs: IEEE 802
Working Groups and Study Groups
802.1 Higher Layer LAN Protocols Working Group
Try to unify some issues for all LANs: management, addressing, bridges
802.2 Logical Link Control working Group
Issues in connecting to the network layer
802.3 Ethernet Working Group
802.4 Token bus Working Group
802.5 Token ring Working Group
Wireless LAN Working Group
11a, 11b, 11e, 11g
Wireless Personal Area Network (WPAN) Working Group
e.g. BlueTooth, ...
Broadband Wireless Access Working Group
wireless MAN
Resilient Packet Ring Working Group
Radio Regulatory TAG
Coexistence TAG
Mobile Broadband Wireless Access (MBWA) Working Group
Link Security Executive Committee Study Group   
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

9. Metropolitan Area Networks
Three components
the access network for end-users
at the end-user you may find a LAN again...
connect to long-haul access points
specifically serve enterprises
e.g. file storage, disparate locations
Requirements
diverse access technology
xDSL, cable, telephony, fiber
diverse managerial domains
home/enterprise equipment, PTT, cable company, leased lines
locally: fast, reliable and fair
similar technologies as LAN, if possible
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

10. MANs: examples Regular, special purpose networks
cable TV: just broadcasting and multiplexing of signals across the same physical medium
telephony: full duplex, point to point, connection oriented
electricity
General data communication
re-use existing infrastructure
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

11. Cable and telephony Cable Telephone need to add two-way communication
sharing of cable segments
Telephone
low bandwidth UTP
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

12. Wide Area Networks Long-range geographical distribution
Separation of local net and subnet
different management
subnet: just transport – wires, switches, routers (no hosts!)
Path-oriented transport through the subnet
Note: subnet
properties will
affect WAN
services
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

13. Routing (path oriented)
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

14. Internetworks Connecting distinct networks
add a subnet: WAN
connect using multi-ported devices in an existing network
e.g. WAN-connected LANs
No clear terminology for Internetworks but
must have different technologies
and different managerial domains
Note:
technical distinctions (WAN, LAN, MAN...) are vanishing
managerial distinctions are most relevant
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

15. Wireless Bandwidth sharing in cells Two modes Overlap issues
point-to-point
base-station (star)
Overlap issues
Three distance scales
Wire-replacement
LAN technology
WAN technology
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

16. Wireless (cnt’d) Wire-replacement LAN technology WAN technology
relatively low bandwidth : main focus on system interconnect (BlueTooth, wireless USB); P2P
cells roughly 10m
LAN technology
include link layer technology
‘high’ bandwidth (i.e., only a factor of slower than wired); e.g. HiperLan, IEEE (‘WiFi’)
cells up to 100m
P2P or base-stations
WAN technology
use long-haul connections, e.g. GSM, GPRS, UMTS
cells up to 3 km
base-stations
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

17. Home networks Special requirements diverse hardware and interconnect
Information, Communication, Entertainment, Control
must work, reliable, foolproof
low cost
much streaming, rather than bursty traffic
high capacity
does not work well with ethernet
evolutionary path
equipment is there for years to stay
safe, secure, privacy protection
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

18. Connecting everything: the Internet
3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking

19. Exercises Exercise 38 on page 84 3-Aug-19
Johan J. Lukkien,
TU/e Computer Science, System Architecture and Networking