Infrastructure Design for IPTV Services IPTV Asia November 8-9, 2006 Grand Copthorne Waterfront Hotel, Singapore Sue Moon Joint Work with Meeyoung Cha (KAIST) W. Art Chaovalitwongse (Rutgers/DIMACS) Gagan Choudhury, Zihui Ge, Aman Shaikh, Jenniver Yates (AT&T)
Path Protection Routing in WDM Mesh Networks [Cha06-2]
Efficient and Scalable Algorithms [Cha06-3]
Service Architecture of IPTV SHO Regional Network Video Hub Office (VHO) 2 SHOs and 40 VHOs across the US customers Regional Network Backbone Distribution Network Super Hub Offices (SHO) VHO VHO Broadcast TV VoD Regional Network How can we provide reliable IPTV services over the backbone network?
Connect geographically close VHOs into regional rings
Inter-connect rings with long haul links
Security is higher than using IP backbone
No access part
Meshed topology (carry “ through ” traffic)
Long haul links SHO SHO VHO VHO
Alt #4: Integrating with Existing Optical Backbone
Multicast capabilities at optical nodes (new technology)
SHOs establish multicast trees, VHO receiving single best stream
Fast-failover is not yet supported in optical multicasting
SHO SHO L1 network VHO
Review: Design Choices Technology Service layer topology Fast-failover Link capacity IP or optical SONET links, fast-reroute, or physically diverse paths Dedicated or shared Hub-and-spoke or highly meshed Access Dual-homed or ring
Design Instances Alt #1 Alt #2 Alt #3 Alt #4 Disjoint paths Dual-homed Time-divisioned Optical Opt-Switched SONET links Fast re-route None .. Dedicated .. Optical .. P2P-DWDM P2P-DWDM-FRR SONET links Fast re-route SONET links Fast re-route Dual-homed .. Ring .. Dedicated .. .. .. IP .. .. .. Ded-IP-HS Ded-IP-HS-FRR Ded-IP-Ring Ded-IP-Ring-FRR SONET links Fast re-route SONET links Fast re-route Dual-homed .. Ring .. Shared .. .. .. IP .. .. .. Int-IP-HS Int-IP-HS-FRR Int-IP-Ring Int-IP-Ring-FRR Fast-Failover Access Type Link-Capacity Layer Design
Cost Analysis: Capital Expense vs Traffic Loads M a +U b : multicast a Gb/s + unicast b Gb/s
Increase in VoD loads has significant impact on the overall cost.
-> Having highly accurate VoD load forecasts is important!
Use redundant SRLG diverse paths from SHOs to VHOs
To be competitive in the market
Each link associated with port / transport cost
Find minimum cost multicast trees
Service Requirements of IPTV
Path Protection Routing Problem SHO SHO VHO VHO VHO VHO Backbone VHO Path Protection Routing Problem How to create two multicast trees such that (1) provisioning cost is minimized and (2) VHOs have physically disjoint paths to SHOs?
An SRLG-Diverse Solution: Active Path First 1. Construct a minimum spanning tree from one source 2. Remove all SRLG links of the first tree 3. Build the second minimum spanning tree with remaining links d1 s2 s1 d2 d3 d1 s2 s1 d2 d3 First tree from s1 Second tree from s2 (reduced graph) (a) Active Path First routing, cost=10 risk1 risk2
Trap Situation of APF d1 s2 s1 d2 d3 d1 s2 s1 d2 d3 First tree from s2 Fail to find second tree from s1 (b) Active Path First routing, trap situation risk1 risk2
Step2: For each VHO, make sure SRLG counterpart part path exists
Step3: Find the missing paths all together using ILP
SHO SHO VHO VHO VHO Does SRLG-diverse counterpart path exist? Yes! Then, fix as solution. Does SRLG-diverse counterpart path exist? No! Then, replace with SRLG diverse paths. Not possible! SRLG diverse SRLG diverse Minimum spanning tree Find missing paths w/ ILP
Capital Expense Comparison Net5 (800sec) Net6 (2sec)