Cabletron Systems HSIM-W6 manual Inverse Multiplexing, Firmware Data Compression

Chapter 2: About the HSIM-W6

Inverse Multiplexing

NOTE

Cabletron Systems products that support Inverse Multiplexing (IMUX), such as the HSIM-W6, CSX400, and HSIM-4T1, must exist on both ends of the WAN link for the IMUX function to work.

Both bridging and routing functions are disabled when using the IMUX function.

Cabletron Systems Inverse Multiplexing (IMUX) feature provides enhanced throughput for users by doing each of the following:

•The IMUX function evenly distributes a data packet stream from the LAN interface through the two WAN interfaces on the HSIM-W6. Since the data traffic is equally shared between the two Full T1 interfaces, each with 1.5 Mbps throughput, the total throughput over the logical link is 3 Mbps, or 6 Mbps full-duplex operation with the optional hardware compression module (CSX-COMP/ENCR) installed in the HSIM-W6.

•The IMUX function passes packet sequence information over the WAN using the Point-to-Point Protocol (PPP) to support data coherency on both ends of the link.

•Data packet streams received by the WAN interfaces on the other end of the WAN link are then recombined, ordered, and transmitted to the LAN interface.

•The IMUX function is fully configurable using QuickSET, which is discussed in the Bridging and Routing Configuration section of Chapter 4 and the MIB Navigator command set discussed in Chapter 6.

Firmware Data Compression

The STAC Electronics Stacker LZS Compression algorithm provides a minimum of 2:1 firmware data compression for the HSIM-W6 over PPP and Frame Relay. Firmware data compression is supported in software on each WAN interface for line speeds of up to 256 Kbps per WPIM, which is equivalent to four DS0 channels. To use data compression, compatible equipment, (such as the HSIM-W6, CSX400, and CSX200 or other vendors’ equipment which conforms to the applicable standards), must be in use at both ends of the WAN link. This firmware method of data compression is used as the default, if the hardware compression module is not installed.

10 HSIM-W6 User’s Guide