IP Optical Networks - Electrical Engineering DepartmentIP光网络-电气工程系

合集下载
  1. 1、下载文档前请自行甄别文档内容的完整性,平台不提供额外的编辑、内容补充、找答案等附加服务。
  2. 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
  3. 3、如文档侵犯您的权益,请联系客服反馈,我们会尽快为您处理(人工客服工作时间:9:00-18:30)。

IP/WDM integrated routing - Problem statement
Develop algorithms for integrated management of routing data in IP over WDM networks
Problem space
Solution space
SDL: Simplified Data Link
•provides length-based delineation instead of flag-based delineation
IP over WDM - Network architectures
R 1
SXC
R 2
With and without SONET/SDH multiplexing
IP over WDM - Protocol stacks
1
2
3
IP AAL5 ATM
SONET/SDH
WDM
IP PPP HDLC
SONET/SDH
WDM
IP
SDL
SONET/SDH
WDM
IP: Internet Protocol AAL5: ATM Adaptation Layer 5
[1] W. Simpson, “PPP over SONET/SDH,” IETF RFC 1619, May 1994.
Generic integrated approach (not specific to IP)
Solve four sub-problems:
1. Determine virtual topology to meet all-pairs (source-destination) traffic 2. Route lightpaths on the physical topology 3. Assign wavelengths 4. Route packet traffic on the virtual topology
IP over WDM without multiplexing capabilities in
intermediate layers
2-layer problem
IP over WDM with multiplexing capabilities in
intermediate layers
3 or 4-layer problem
IP-centric and IP multi-service networks: Voice over IP, Video over IP, ...
IP over WDM - Motivations
WDM reduces costly mux/demux function, reuses existing optical fibers.
“IP over SONET,” IEEE Communications Magazine, Vol. 36, No. 5, May 2019, pp. 136-142.
HDLC: High-level Data Link Control
WDM: Wavelength Division Multiplexing
“Greedy” distributed solution Monitor lightpath utilization and change allocations of lightpaths between pairs or routers accordingly
Centralized system-wide optimal solution
IP over WDM - Network architectures
Multiplex several SONET OC3, OC12, OC48 interfaces on to one fiber using WDM
R
R
WDM
WDM
Multiplexer
Multiplexer
R
IP PPP HDLC
SONET/SDH
OC3/OC12/OC48
IP PPP HDLC
SONET/SDH
WDM
R
IP PPP HDLC
SONET/SDH
OC3/OC12/OC48
* Could even multiplex some IP/AAL5/ATM streams with IP/PPP/HDLC streams
R 3
WDM NE
WDM NE
R 6
WDM NE
R 5
ADM
ADM SONET/SDH ring
ADM
WDM
NE
R
R
4
7
SONET/SDH
SXC Cross-Connect
ADM
SONET/SDH Add-Drop Multiplexer
R
IP Router
WDM NE
WDM CrossConnect or Add-Drop Multiplexer
Centralized
Distributed
With SONET cross-connects, it becomes a three-layer problem
With SONET cross-connects and ATM switches, it becomes a four-layer problem
Outline
IP over WDM Motivations Protocol stacks Network architectures
IP/WDM integrated routing Problem statement
Two-layer routing problem
Possible solution strategies
Two-layer routing problem
R
R
1
3
R 4
R 2
R 6
R 5
R 7
Virtual Topology
R 3 R 1
OXC
OXC
R 6
R 5
OXC
RHale Waihona Puke R27OXC
R
4
Physical Topology
What are the benefits/costs (in terms of network performance and management complexity) of performing traffic/QoS management and survivability at the WDM optical layer instead of at the IP layer?
• All three protocol stacks can be used in conjunction with SONET/SDH multiplexing • Even without SONET/SDH multiplexing (for example R3 to R6 communication), since IP routers have SONET/SDH interfaces, IP over WDM could involve a SONET/SDH layer
Limit on the number of optical amplifiers a lightpath can traverse before requiring electronic regeneration
All wavelengths amplified equally at an optical amplifier
Without wavelength changers at OXCs (Optical Cross-Connects), wavelength assignments to lightpaths need to ensure availability of selected wavelength on all fibers on the lighpath
Integrated routing at IP and WDM layers
• Interaction with the routing protocols used in IP networks
Greedy distributed solution Network-wide centralized solution
New high-capacity networks To meet this anticipated need, carriers in the US are in the process of deploying high-capacity networks (OC-48~2.5 Gbps, and soon OC-192 ~10Gbps) for the sole purpose of delivering Internet data Some new carriers are building networks customized for IP traffic (most existing “transport” networks were built primarily for voice traffic)
Alternative to new fiber installation Consolidation of legacy systems Maximizes capacity of leased fibers Future-proofing of new fiber routes WDM allows high flexibility in expanding bandwidth Cost Reduction - integrating optics and eliminating mux stages Operation Efficiency - elimination of redundant protocol layers Transport Efficiency - elimination of transport protocol overhead Emergent technology is evolving WDM from optical transport (point-topoint line systems) to true optical networking (add-drop multiplexers and cross-connects)
ATM: Asynchronous Transfer Mode
[2] J. Manchester, J. Anderson, B. Doshi and S. Dravida,
SONET: Synchronous Optical NETwork PPP: Point-to-Point Protocol
R 1
R
R
3
6
OXC
Optical Amplifier
R 5
OADM
OXC
R
7
OXC
R
R
4
2
Solution strategies
Integrated routing at the IP and WDM layers Interaction between existing routing schemes at the IP layer and this new integrated solution
Extensions Summary
IP over WDM - Motivations
IP traffic volumes Traffic volumes on the Internet double every six months Aggregate bandwidth required by the Internet in the US by the year 2019 is expected to be in excess of 35 Terabytes/sec
Is there a hybrid or cooperative approach that is more optimal given a set of realistic performance and complexity constraints?
What is particular about this (IP/WDM) 2-layer routing problem?
相关文档
最新文档