Chapter 4 FCIP over IP/MPLS Core
Typical Customer Requirements
The requirements are as follows:
•FCIP transport over an optimized IP/MPLS network
•Some type of compression mechanism (software or hardware)
•Security mechanism (IPSec, encryption, and VPN networks)
•
Compression
The primary objective of compression is to reduce the amount of overall traffic on a particular WAN link. This is achieved when a data rate equal to the WAN link speed is compressed, thereby reducing the total amount of data on the WAN link. In this case,
There are several types of compression algorithms. The most common type used in data networks is lossless data compression (LZS). This type of compression converts the original data into a compressed format that then can be restored into the original data. The service adapter modules
The LZS compression algorithm works by searching for redundant data strings in the input data stream and then replaces these strings with data tokens that are shorter in length than the original data. A table is built of these string matches, pointing to previous data in the input stream. The net result is that future data is compressed based on previous data. The more redundant the data in the input stream, the better the compression ratio. Conversely, the more random the data, the worse the compression ratio will be.
The compression history used by LZS is based on a sliding window of the last 2000 bytes of the input stream. When the data is transmitted, it contains both literal data and compressed tokens. Literal data are input data streams that cannot be compressed and are transmitted uncompressed. Compressed tokens are pointer offsets and data length that point to the compression history table. The remote side rebuilds the data from the compressed history table based on the pointers and length fields.
Note A full description of IPPCP and LZS are available in RFC 2395 and in ANSI
Compression Support in Cisco MDS
Both software- and
The
Data Center High Availability Clusters Design Guide
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