Due to the rapid evolution of Internet as well as services over the Internet, including high bandwidth consuming applications like audio and video streaming, it has become need of the day to enhance the Internet infrastructure for bandwidth efficiency.
One of the present day biggest challenges of networks is the audio/video transmission in real time. Developed by the Internet Engineering Task Force, Multiprotocol label Switching (MPLS) allows networks to offer several services on the single network architecture with improved forwarding speed of routers by solving the problem of longest prefix match in IP networks. Internet Protocol datagram encapsulates payload received from above layer and adds to its own header information. Thus each protocol layer adds its own header with the information related to the layer. This is a disadvantage of a bigger packet header size such as IPv4/UDP/RTP header of 40 bytes compared to the payload size which leads to excessive overhead in case of real-time multimedia applications. Bandwidth can be conserved by reducing the amount of redundant IP header transmitted with every packet for the same packet stream through header compression techniques. The header compression mechanisms have several short comings such as a problem that they work on hop-by-hop basis. The packet is compressed by the compressor and decompressed by the decompressor and for header compression to work; these are connected directly not through any intermediate node, not even a layer 3 device such as a router. In addition to this, there is a limit in the number of compressed flows that a router can take.
The objective of this book is to propose header compression technology which can be implemented over MPLS and used as a bandwidth conserving technology. This will solve the problems of hop-by-hop compression/decompression as the compression of packets is not hop-by-hop rather the compression is per Label Switched Path (LSP) of MPLS network from ingress to egress Label Switched Routers. This will also handle packet reordering in addition to allowing numerous flows at the same time. The current work in the area, both standardized as well as ongoing research has been discussed in detail and also the problems that are yet to be addressed are examined. This approach also increases the bandwidth efficiency as well as processing scalability with respect to the maximum number of simultaneous flows.
Table of Contents
- Introduction
- Motivation
- ROHC over MPLS
- Background
- Multi Protocol Label Switching (MPLS)
- Header Compression
- Header Compression Techniques
- Van Jacobson Header Compression (VJHC)
- Space Communication Protocol Specification (SCPS)
- Internet Protocol Header Compression (IPHC)
- RTP Header Compression
- Extended Compressed Real Time Protocol (ECRTP)
- Robust Header Compression (ROHC)
- Header Compression over MPLS
- Robust Header Compression (ROHC)
- Analysis of Protocol Headers
- IP Header Fields
- UDP Header Fields
- RTP header fields
- Complete IPv4/UDP/RTP Header
- Functional Analysis of ROHC
- Compressor and decompressor finite state machines
- Compressor states
- Decompressor states
- Modes of Operation
- Unidirectional Mode (U-mode)
- Compressor states and logic (U-mode)
- Decompressor states and logic (U-mode)
- Bidirectional Optimistic (O-mode)
- Compressor states and logic (O-mode)
- Decompressor states and logic (O-mode)
- Bidirectional Reliable mode (R-mode)
- Compressor states and logic (R-mode)
- Decompressor states and logic (R-mode)
- Mode Transitions
- Data structures, Parameters and Profiles
- Per-channel parameters
- Per-context parameters
- ROHC Profiles
- Encoding Methods
- Least Significant Bits (LSB) Encoding
- Window-based LSB (WLSB) Encoding
- Scaled RTP Timestamp Encoding
- Timer-based RTP Timestamp Encoding
- IPv4 Identifier (IP-ID) Offset Encoding
- Chapter Conclusion
- Robust Header Compression over MPLS
- Flow Chart for Compressor and Decompressor
- MPLS Pseudo Wires
- MPLS Header Compression Pseudowire Setup, Negotiation and Signaling
- Packet Reordering
- Bandwidth efficiency through header compression.
- Addressing the limitations of traditional header compression techniques.
- Implementing ROHC over MPLS for enhanced network performance.
- Improving scalability and reliability for real-time multimedia applications.
- Packet reordering and managing multiple flows concurrently.
- Introduction: This chapter introduces the challenges of bandwidth limitations and packet reordering in real-time multimedia applications, emphasizing the need for efficient bandwidth utilization. It discusses the role of IP and TCP/IP protocols in network communication and the evolution of the internet.
- Background: This chapter provides a comprehensive overview of Multiprotocol Label Switching (MPLS), a technology that allows networks to offer various services on a single infrastructure. It also covers the concept of header compression and examines various techniques, such as Van Jacobson Header Compression (VJHC), Space Communication Protocol Specification (SCPS), Internet Protocol Header Compression (IPHC), and others.
- Robust Header Compression (ROHC): This chapter delves into the details of ROHC, a robust header compression technique that can be used for efficient bandwidth conservation. It analyzes the structure of IP, UDP, and RTP headers, explaining how ROHC operates through compressor and decompressor states and different modes of operation. It also discusses the data structures, parameters, and profiles of ROHC, along with encoding methods like Least Significant Bits (LSB) encoding and Window-based LSB (WLSB) encoding.
- Robust Header Compression over MPLS: This chapter explores the implementation of ROHC over MPLS networks, highlighting the benefits of this approach in addressing the challenges of hop-by-hop compression. It discusses the flow chart for compressor and decompressor operations, the concept of MPLS pseudo wires, and how ROHC can effectively handle packet reordering within the MPLS network.
Objectives and Key Themes
This book aims to propose a header compression technology that can be implemented over MPLS networks to conserve bandwidth. It addresses the limitations of hop-by-hop compression techniques, such as the need for direct connection between compressor and decompressor. This work explores the use of ROHC for efficient header compression within MPLS networks, providing a more scalable and reliable solution for bandwidth management.
Chapter Summaries
Keywords
This work focuses on the use of Robust Header Compression (ROHC) technology implemented over Multiprotocol Label Switching (MPLS) networks for bandwidth optimization. The core concepts include header compression techniques, packet reordering, bandwidth efficiency, scalability, and reliability in real-time multimedia applications. Key terms also include IP, TCP/IP, UDP, RTP, compressor and decompressor states, modes of operation, and MPLS pseudo wires.
- Citation du texte
- Mohammad Ahsan Chishti (Auteur), Shaima Quershi (Auteur), Ajaz Hussain Mir (Auteur), 2016, Robust Header Compression (RoHC) over Multiprotocol Label Switching (MPLS) Networks, Munich, GRIN Verlag, https://www.grin.com/document/379485
