Carrier Networks(Chapter 4)

Long Haul/Core NetworkMetro NetworkAccess Network

TechnologiesConvergence

SignalingDigital Hierarchy/SONET

Public Network Categories• Core• Long Haul – hundreds of miles between sites• Very high capacity

• Metro Networks• City – wide• Connect to Core

• Access/Local Networks• Last Mile/Local Loop• Connects Buildings and Homes

Core: Long Haul

• High Bandwidth• 100G • DWDM• Some TDM – mostly converted to IP

• Technologies• SONET• Ring

• GigE• MPLS

Core: Long HaulNetwork Convergence

• TDM to IP convergence• Why Core first?• Fewer nodes/switches• Higher bandwidth, better efficiency• End customers convert to IP at different times

• Metro Networks• Access/Local Networks• Customer’s staying TDM

• Investment in equipment• Security• Slow to adop

Network Convergence

• Hybrid networks still during transition• Gateways/Softswitches/Class 5 TDM switches• Optical Transport Network (OTN)• Legacy SONET/TDM traffic + New GigE/IP

traffic• Encapsulation of legacy SONET traffic in OTN

frames• Synchronous (evenly spaced) – SONET, TDM (T1,

T3)• Asynchronous (irregular intervals/dynamic) – GigE

• All done in one box

Metro Networks• Middle bandwidth• 2.5G, 10G• Redundancy• Connect COs together• Aggregate Local traffic onto Core

Access/Local Networks• Local loop• Still mostly copper• Trending to fiber• Expensive• Bandwidth bottleneck• POTS• DSL• T1/T3• Ethernet• Cable Operators• Passive Optical Network (PON)• Similar to SLC (1 pr. Fiber/ 32 sites)

Signaling• Control communications between network

nodes• Signaling System 7 (SS7)• SIP• Call setup/disconnect; Features; Billing;

Roaming; Access/security• In-Band• Out of Band

Digital HierarchySONET

Electrical• DS0 – 64KB• DS1 – 1.544MB (24 DS0s)• DS3 – 45MB (28 DS1s)

Optical (SONET)• OC3 – 155MB (3 DS3s)• OC12 – 622MB (12 DS3s)• OC48 – 2.5GB (48 DS3s)• OC192 – 10GB (192 DS3s)• OC768 – 40GB (768 DS3s)