IP router interconnection

Transcript

IP over …
… ATM … SDH … DWDM
Mario Baldi
Politecnico di Torino
(Technical University of Torino)
http://staff.polito.it/mario.baldi
IPinterconnection - 1
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IP Everywhere. Anything else?
Wide Area
?
Which is the Best Interconnection
Topology?
Even if You Know It, You Know It
only Now!

It can change on a monthly base
different
customers
different customer needs

It can change on a weekly base
events

It can change on a daily base
business
users during week-days, residential
users during the week-end

It can change on a hourly base
business
hours
evening entertainment
IP over Photons

Routers are connected by optical fibers
The
optical signal transmitted by a router is
received by the other

Layer 2 framing as in any synchronous
transmission
PPP
IEEE
802.3
Pros and Cons
&No overhead
'Physical connections: no reconfigurability
'One interface per connection
'No standard management infrastructure
IP over Dense Wavelength
Division Multiplexing (DWDM)
Many transmissions with different
wavelengths (colors) on the same fiber
Multiplies fiber capacity
Optical switches with wavelength routing
Layer 2 framing: PPP

Pros and Cons
&Very high capacity
&Virtual connections with optical routing
'No standard management infrastructure
'Static multiplexing

Reconfiguration Flexibility?

One interface for many connections?
How
about IP addresses?

One per physical interface?

One per wavelength?
IP over SONET/SDH
(Synchronous Optical NETwork
Synchronous Digital Hierarchy)
Physical layer framing
Cross connect
Fine allocation granularity
Management framework
Layer 2 framing: PPP
Transmission Hierarchy
PDH Hierarchy
SDH Hierarchy
Europe
USA
USA: SONET
E1
2.048 Mbps
T1 - DS1
1.544 Mbps
OC-1c / STS-1c
51.84 Mbps
E3
34.368 Mbps
T3 - DS3
44.736 Mbps
E4
139.26 Mbps
Europe: SDH
OC-3c / STS-3c
155.52 Mbps
STM-1
155.52 Mbps
OC-12c / STS-12c
622.08 Mbps
STM-4
622.08 Mbps
OC-48c / STS-48c
2.4 Gbps
STM-12
2.4 Gbps
Physical Architecture
Section: fiber optics trunk between transceivers
Line: sequence of sections between devices which

operates on the frame
T
T
Repeater
Section
Section
Repeater
Section
Line
Section
Line
Path
SONET/SDH
MUX
T
Add/Drop
MUX
Path: end-to-end leased line
SONET/SDH
MUX

T
T
T
Protocol Architecture
Photonic Layer: fiber, laser
Section Layer: frames, OAM (Operation

Administration and Management)

Line Layer: synchronization, multiplexing,
switching, OAM

Path Layer: end-to-end data (bytes) transfer
Terminal
Repeater
Multiplexer
Higher Layer
Higher Layer
Envelope
Path Layer
Line Layer
Section Layer
STS-N / STM-N Block
Frame
Photonic Layer
Path Layer
Line Layer
Line Layer
Section Layer
Section Layer
Section Layer
Photonic Layer
Photonic Layer
Photonic Layer
Light
Terminal
Frame Format
STS-1: 810 octets every 125 μs Æ 51.84 Mbps
90 octets
9 octets
0 μs
3 octets
Synchronous Payload Environment (SPE) 87 octets
A1
A2
C1
J1
B1
E1
F1
B3
D1
D2
D3
C2
H1
H2
H3
G1
B2
K1
K2
D4
D5
D6
H4
D7
D8
D9
Z3
D10
D11
D12
Z4
Z1
Z2
E2
Z5
Section Overhead
Payload
F2
Line Overhead
Payload
Path Overhead
125 μs
Pros and Cons
&Standard OAM architecture
&Virtual connections
'One interface per connection
'Static multiplexing
'Limited reconfiguration flexibility
IP over ATM
(Asynchronous Transfer Mode)

Cell switching
flexible
multiplexing
Semi-permanent and switched virtual
connections
Layer 2 protocol

no
need for
layer 2
framing
Pros and Cons
&Multiple connections per interface
&Total reconfiguration flexibility
&Support for other services (e.g., frame relay)
&Flexible multiplexing
'High protocol overhead (more than 10%)
IP over FR
(Frame Relay)

Frame switching
flexible
multiplexing
Semi-permanent virtual connections
Layer 2 protocol

no
need for layer 2 framing
Pros and Cons
&Large installed base
'No Quality of Service Guarantees
Why is another packet switching layer needed?
Because IP lacks traffic engineering capability
MPLS
(Multi-Protocol Label Switching)

Frame switching
flexible
multiplexing
Dynamic virtual connections (label switched
paths)
Layer 2 protocol tightly integrated with layer 3

Pros and Cons
&One control plane: no “IP over”
'No Quality of Service Guarantees