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Course goals Advanced topics in networking
cross-layer vision advanced functionalities design, management
Organization 36 h course, 18h networking lab demos, exercises, questions, homework slides are not exhaustive - you must take notes and ask
questions!
Your team course: A. Duda, J-L. Richier, P. Laforgue lab: M. Heusse, S. Viardot
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Networking lab
Important part of the course perform required operations, write lab reports cannot be repeated
grade < 8, you repeat your year!
Goals acquire practical knowledge use Zebra as a router emulator
Rooms D200 and D201: 80 PCs with multiple network interfaces network equipement: hubs, switches, routers isolated from the rest of the network
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Contents Introduction
network architectures
Interconnection Layer 2 VLANs and bridges, spanning tree protocol
Interconnection Layer 3 IPv6 Routing (RIP, OSPF, BGP)
Congestion control Quality of service MPLS, multicast Mobility Network management
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Course support Web site
http://duda.imag.fr/3at
L. Toutain "Réseaux locaux et Internet", 3me édition,Hermes, 2003
C. Huitema "Le routage dans l'Internet", Eyrolles,1995.
R. Perlman "Interconnexions : ponts et routeurs",Addison-Wesley, 1994.
Gisèle Cizault "IPv6", O'Reilly 2001.
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Overview
Network architectures protocol architectures
how entities cooperate?
interconnection structure which entities are connected?
related protocols how and where different functionalities are implemented?
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Introduction:network structure,architecture and protocols
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Layered Protocol Stack
Managing complexity a layer corresponds to an independent module (protocol
entity)
A layer supports common data format - PDU (Protocol Data Unit) rules of cooperation: peer-peer procedures service interface: SAP (Service Access Point)
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Protocol Architecture
Protocol entity provides a set of services, eg.
connect, send
data multiplexing/demultiplexing construction/analysis of PDUs execution of procedures
Protocol unit (PDU) header: control functions opaque data
Procedures actions to perform protocol functions: eg. lost packet
retransmission
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Protocol architecture
SAP
PDU PDU
procedures
Lower layer protocols
Protocol entity Protocol entity
data
multiplexingSAP
data
demultiplexing
layer nlayer n
layer n-1 layer n-1
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Internet design principles
Cerf and Kahn’s internetworking principles: minimalism, autonomy - no internal changes required to
interconnect networks best effort service model stateless routers decentralized control
define today’s Internet architecture
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Internet protocol stack
Application: supporting networkapplications FTP, SMTP, HTTP, OSPF, RIP
Transport: host-host data transfer TCP, UDP
Network: routing of datagrams fromsource to destination IP
Link: data transfer between neighboringnetwork elements PPP, Ethernet
Physical: bits “on the wire”
Application
Transport
Network
Link
Physical
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ATM protocol stack
Application: native applications, otherprotocols LAN Emulation, IP, Signaling
Transport: host-host data transfer SSCOP
Adaptation: adapt the ATM layer todifferent types of applications circuit emulation, real-time data AAL5 suitable for IP traffic
ATM: cell switching over virtual circuits Physical: bits “on the wire”
Application
Transport
Adaptation
ATM
Physical
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LAN stack
Management: e.g. construct forwardingtables SNAP: Spanning Tree protocol
LLC: multiplex different protocols IP, IPX, SNAP
MAC: medium access 802.3 (Ethernet), 802.4 (Token Ring), 802.5
(Token Bus), 802.11 (Wi-Fi)
Physical: bits “on the wire”
Management
LLC
MAC
Physical
Data-link
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Network architecture
Logical structure interconnected entities
Protocol architecture how entities cooperate
Related protocols different functionalities
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Interconnection structure - layer 2
host
switch(bridge)
interconnectionlayer 2
VLAN
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Interconnection at layer 2
Switches (bridges) interconnect hosts logically separate groups of hosts (VLANs) managed by one entity
Type of the network broadcast
Forwarding based on MAC address flat address space forwarding tables: one entry per host works if no loops
careful management Spanning Tree protocol
not scalable
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Transport
Network
Physical
Application5
4
3
2
1
MAC
Physical
MACL2 PDU(MAC Frame)
host switch (bridge)
LLC
Protocol architecture
Switches are layer 2 intermediate systems Transparent forwarding Management protocols (Spanning Tree, VLAN)
LLC
L2 PDU(LLC Frame)
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802.3
LLC
SNAP
data
-link
Physical layer
Protocols
Ethernet v2
netw
ork
IP
data
management
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Interconnection structure - layer 3
host
router
switch(bridge)
interconnectionlayer 3
VLANsubnetwork 1 subnet 3
subnet 2
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Interconnection at layer 3
Routers interconnect subnetworks logically separate groups of hosts managed by one entity
Forwarding based on IP address structured address space routing tables: aggregation of entries works if no loops - routing protocols (IGP - Internal Routing
Protocols) scalable inside one administrative domain
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Protocol architecture
Routers are layer 3 intermediate systems Explicit forwarding
host has to know the address of the first router
Management protocols (control, routing, configuration)
Transport
Network
Physical
Application5
4
3
2
1
MAC
Physical
MACL2 PDU
(MAC Frame)
host switch (bridge)
LLC LLC
Transport
Network
Physical
Application 5
4
3
2
1
MAC
router
LLC
L2 PDU(MAC Frame)
L3 PDU(IP packet)
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-link
Protocols
Ethernet v2
netw
ork
IP
routing
ARP
TCP
OSPF RIPDHCP
ICMP
tran
spor
tap
plic
atio
n
IGMP
UDP
DNS
naming configuration routing
control groups
addressresolution
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Autonomous systems
host
switch(bridge)
interconnectionlayer 2
interconnectionlayer 3
VLANsubnetwork
autonomoussystem
borderrouter
internalrouter
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Long-haul links
Fiber at physical layer (SONET/SDH) Dense Wave Division Multiplexing (DWDM)
one color of the light λ
Different technologies ATM Frame Relay POS (Packet over SONET/SDH)
Type of the network NBMA (Non Broadcast Multiple Access) or point-to-point
Complex protocol hierarchies IP over ATM
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Protocol architecture
IP
SDH
ATM ATM cell
router ATM switch
AAL5
router
ATM cell
L3 PDU(IP packet)
DWDM λ
SDH
ATM
DWDM λ
IP
SDH
ATM
AAL5
DWDM λ
PPP
SDH
router router
DWDM λ
PPP
SDH
DWDM λ
L2 PDU(PPP frame)
IP
L3 PDU(IP packet)
IP
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Internet
NAP, GIX, IXP
subnetworks
borderrouter
autonomoussystem
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Interconnection of AS
Border routers interconnect AS
NAP or GIX, or IXP exchange of traffic - peering
Route construction based on the path through a series of AS based on administrative policies routing tables: aggregation of entries works if no loops and at least one route - routing protocols
(EGP - External Routing Protocols)
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-link
Protocols
Ethernet v2
netw
ork
IP
routing
ARP
TCP
BGP
ICMP
tran
spor
tap
plic
atio
n
control
addressresolution
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Residential access
router
modeminterconnectionlayer 3
POTS(phone network)
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Residential access
Modem connects a host to the first router
Point-to-point encapsulation (PPP) activate a connection authenticate the user negotiate network address multiplex different protocols (IP, IPX)
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Protocol architecture
Transport
Network
Physical
Application5
4
3
2
1L2 PDU
(PPP Frame)
host
PPP
Transport
Network
Physical
Application 5
4
3
2
1
router
PPP
L3 PDU(IP packet)
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Protocols
IP
header compression
PPP
LCP
NCPCHAP
PAP
data negociationauthentication
data
-link
netw
ork
Physical layer
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Residential access
router
ATMswitch
interconnectionlayer 3
ATMnetwork
DSLAM (ATU-C)DSL Access Multiplexer
ATU-RADSL modem/bridge/router
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Protocol architecture
IP
ADSL
ATM ATM cell
DSLAM
AAL5
router
ATM cell
L3 PDU(IP packet)
ADSL/SDH
ATM
IP
SDH
ATM
AAL5
IP over ATM requires fixed IP address
ADSL modem
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Protocol architecture
IP
ADSL
ATM ATM cell
DSLAM
AAL5
router
ATM cell
L3 PDU(IP packet)
ADSL/SDH
ATM
IP
SDH
ATM
AAL5
PPPoA PPPoA
PPP over ATM (PPPoA) multiple users share ADSL link
ADSL modem
L2 PDU (PPP frame)
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Protocol architecture
Ethernet
ADSL bridge/router
L3 PDU(IP packet)
Ethernet
ADSL
ATM
AAL5
host
Physical
LLC/SNAP
PPPoE PPPoE
IP IP
Ethernet
Physical
PPPoE
IP
DSLAM
ADSL/SDH
ATMATM cell
PPP over Ethernet (PPPoE) multiple users share ADSL link
L2 PDU (PPP frame)
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Conclusion
Complex architectures other types of networks used as data links
Internet Rapid growth
scalability
No central control coherent development
Three level hierarchy host, subnetwork, autonomous system manage complexity
Advances larger address space - IPv6 performance - quality of service, e.g. DiffServ security - Virtual Private Networks (VPN)
