Transcript Overview of work in TERENA

Valentino Cavalli
TERENA
Ways and means
of seeing the light
Technical opportunities and
problems of optical networking
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
1
Background
• Study on developments of equipment for optical
transmission, switching and routing
• Technical sessions at:
– Initial Workshop
– Operator’s Workshop
– NREN’s Workshop
• TF-NGN/ASTON group:
– Direct involvement in meetings with vendors,
Discussion at TF-NGN meetings, white paper of lower
layer research areas
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
2
Index
• Current networking environment,
emerging factors and challenges for
NRENs
• Technology facts and developments
concerning fibres, transmission
equipment, switches and routers
• Consequences in terms of network
management and network architecture
• Conclusions
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
3
Current Environment
• Shared IP, basically best-effort and
ubiquitous any-to-any service
• Networks currently over-provisioned
(with exceptions in some countries and
generally at the campus level)
• Guaranteed performance and traffic
engineering mostly at the IP routing layer
• Simple and transparent model, easy
management
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
4
Emerging factors
• Access to fibre much easier than in the past: universities
and NRENs exploring a DIY approach towards network
infrastructure
• Developments of WDM equipment, opto-electronics and
all-optical devices.
• Increased availability of bandwidth but also increased
need
• Changes in traffic patterns
• Need for high-bandwidth p2p connectivity between a
limited number of locations to support large data flows
• Dynamic, on-demand bandwidth management, requiring
network-aware middleware
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
5
What are NRENs facing?
• DIY approach towards network infrastructure, but to what
extent? Campus, National, International?
• Depends on reach, but is actually happening at Campus
and National level.
• More complex internationally, not only because of
distance, but also need to provide services end-to-end
across multiple administration domains
• New expertise also required
• Change of traditional customer-supplier relationship with
carriers, more collaboration is possible and needed
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
6
Technology
• Physical transmission layer (Optical
fibre)
• WDM equipment:
– End-points, add-drop multiplexers,
regenerators, amplifiers
• Switches
• Routers
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
7
Optical transmission
• Wide availability of fibre but limited to certain locations
(even within a country)
• Need for amplification, signal regeneration, dispersion
compensation: limitations of existing fibre plants
• Different access options:
– leased connectivity, managed fibre, long-term lease,
fibre ownership
• Cost effectiveness: Dark fibre vs managed wavelength
• Issue: Operation might require install and maintain
equipment at remote locations for NRENs
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
8
WDM equipment
• transmission technology allowing today
(DWDM) up to 40 Gbit/s on a single
wavelength, up to 160-190 wavelength per
fibre, up to several Tbit/s per fibre
• Analogue technology, standardisation limited to
ITU Wavelength Grid, limited interoperability
• Lot of dependency on fiber type and quality,
dispersion, etc., needs to be tailored to each
specific situations
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
9
Capacity and reach
• Transmission capacity at 40Gbit/s per wavelength
(channel) available, multiples of 40Gbit/s being tested
– Costs of the electronics impact on interfaces, router
line-cards, etc.
– Market demand not clear yet
• Depending on fibre type current 2.5-10Gbit/s systems
require regeneration after 4-5 amplification spans (spans
varying between 80-120km) so 400-600km, new
generation ULH systems can reach up to 4000km
• Experiences with NIL up to 230km (GE and 2.5Gbit/s),
180km at 10GE
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
10
Optical switching
• Wavelength termination and signal regeneration require
OEO conversion, transponders are very expensive, but
OOO Switching equipment terminates only local traffic
and does not impact on express traffic
• OOO switches are signal-transparent, lower unit cost,
footprint and lower operational costs
• Generally support a variety of framing interfaces
SONET/SDH, GE, 2.5, 10 GE, G.709, GFP
• Electrical technology still needed at user interface for
multiplexing and bandwidth grooming
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
11
Routing
• Wide range of functionality supported: IPv6,
multicast, QoS, MPLS
• G-MPLS already available, but little
interoperability
• Support for multiple 10Gbit/s, 40Gbit/s bit-rate
interfaces is available, but line-rate interfaces
exploiting the full capacity of transmission links
are not there yet
– Cost of ASICs – mass production
• Driving introduction of 40Gbit/s
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
12
Management
• A mix of networking elements requiring a unified
control plane and sophisticated management
systems to seamlessly manage network and
transport layer
• several signalling protocols being standardised
by IETF and ITU-T
• Inter-operability, and multi-domain management
still represent a challenge
– More cooperation among network operators
to provide e2e services across domains
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
13
Network architecture
• Shared IP model,higher meshing? Gigabit core routers
increasingly expensive at higher speed
• Circuit switching addressing “heavy” user needs?
• Over-provisioning is no longer a cost effective solution
• Simple extension of shared IP model does not scale,
need to explore hybrid network architecture solutions
– Routers and switches can be combined in providing a
flexible network architecture
– Limited cost saving but more efficient way of serving
users
– Engineering traffic not only at layer 3 but also at
layers 2 and 1
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
14
Conclusions
• Simple extension of shared IP model does not scale,
need to explore hybrid solutions
– Circuit/lambda switching coexisting with IP routing
• 40Gps/s will happen soon
• Exploitation of dark fibre depend on economics and reach
– At less than 250km NIL solutions seem viable
• Management functions crossing multiple domains are
being developed, but:
– more work needed in standardisation of signalling
protocols
– Need to address complexity of providing end-to-end
services in multi-domain (and multi-vendor)
environment
Workshop, Bad Nauheim, 16-17 June 2003
Valentino Cavalli <[email protected]>
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