[Transport Bit] How to Maximize Bandwidth of Air Interface (2)
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Header Compression over Air Interface —Enhancing Encapsulation Efficiency On TCP/IP networks, ideally only the payloads are transmitted. However, IP headers and ETH headers are added to preloads to satisfy packet addressing and forwarding requirements. As a result, packet lengths increase which in turn leads to low bandwidth efficiency. On TCP/IP networks, ideally only the payloads are transmitted. However, IP headers and ETH headers are added to preloads to satisfy packet addressing and forwarding requirements. As a result, packet lengths increase which in turn leads to low bandwidth efficiency. In microwave systems, air interface bandwidth is scarce. As the microwave links are P2P-based, address information is not required. Finding a way to shorten the length of various packet headers would significantly improve bandwidth utilization. The following example uses product packaging to illustrate how payload (goods) becomes burdened with headers (packaging and containers). Restricted by the load capacity of the transport medium, the more "packaging", the fewer products actually shipped per volume. However, if we transport the goods without packaging (just the needed packing to ensure safe transport), significantly more goods per volume can be delivered. In practice, such a method is widely adopted in international logistics to fully unitize space and lower costs. Header compression over air interface functions in a similar manner to improve bandwidth utilization of ETH services on microwave links. With header compression enabled, the compressor converts the large overheads, such as ETH headers and IP headers, into only a few indicator bytes while the decompressor does the opposite. Header compression over air interface technology greatly increases throughput of microwave links (as measured over the UNI interface). The shorter the frame, the larger the space the header occupies in the packet length. As such, the effect of header compression in saving space is most noticeable in short frames. With header compression enabled and 4096-QAM, it is possible obtain a throughput of 1 Gbit/s in the 40 MHz channel and 1.6 Gbit/s in the 56 MHz channel. As most voice services are carried over short packets, the benefits of header compression are most pertinent to mobile networks. Header compression also provides a better method to cope with burst traffic caused by spikes in voice services. For a NodeB running in a typical traffic model, throughput can increase by approximately 50% with header compression. By compressing ETH, MAC, and IP headers, Huawei RTN 300 and RTN 900 increase the throughput of NodeB/eNodeBs (for handling voice traffic bursts) and maximize air interface bandwidth. ===Link archives (updated 2015-05-26)=== >>>Click here for the latest links
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Hello, thank you for your feedback. The first figure and second figure are related but not same. The first figure shows that a vehicle can carry six boxes of payloads with full headers; the second figure shows that the same vehicle can carry fifteen boxes of payloads by getting rid of headers (outer boxes). So the encapsulation efficiency is increased by header compression. |
Posted by BaraaN at 2017-09-02 18:59 Most of times in our microwave network when we applied header compression the warning alarm of "Port ... |
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