Chapter 4 FCIP over IP/MPLS Core
Typical Customer Requirements
Hardware-based compression is available with SAN-OS version 2.0 and with new hardware (MDS 9216i/MLS14/2). Compression is applied per FCIP interface (tunnel) with a variety of modes available. Beginning with SAN-OS 2.0, three compression modes are configurable with additional support for the MPS-14/2 module.
Compression Modes and Rate
In SAN-OS 1.3, the following two compression modes can be enabled per FCIP interface on the IPS-4 and IPS-8:
•High throughput ratio—Compression is applied to outgoing FCIP packets on this interface with higher throughput favored at the cost of a slightly lower compression rate.
•High compression ratio—Compression is applied to outgoing FCIP packets on this interface with a higher compression ratio favored at the cost of a slightly lower throughput.
In SAN-OS 2.0, three compression modes are available per FCIP interface on the IPS-4, IPS-8, and MPS-14/2:
•Mode 1—Equivalent to the high throughput ratio of SAN-OS 1.3. Use Mode 1 for WAN paths up to 100 Mbps on the IPS-4 and IPS-8; and WAN paths up to 1 Gbps on the MPS-14/2.
•Mode 2—Higher compression ratio than Mode1, but applicable only to slow WAN links up to 25 Mbps.
•Mode 3—Higher compression ratio than Mode 1 and slightly higher than Mode 2. Applicable to very slow WAN links up to 10 Mbps.
The following are the software-based compression options for FCIP for the Cisco MDS 9000 IP Storage Services Module:
•SAN-OS 1.3—Two algorithms: high throughput and high compression
•SAN-OS 2.0—Three algorithms: Modes 1–3
The following is the hardware- and software-based compression and hardware-based encryption for FCIP for the Cisco MDS 9000 Multi-Protocol Services module:
•SAN-OS 2.0—Three algorithms: Modes 1–3
The choice between these solutions should be based on the following factors:
•Available link speed or bandwidth
•Choice of FCIP solution (IPS-8/4 FCIP, MPS-14/2, or PA-FC-1G port adapter)
•New or existing SAN fabric installations
Note For more information, see the following: LZS (RFC 1974), IPPCP with LZS (RFC 2395), Deflate (RFC 1951), and IPPCP with Deflate (RFC 2394).
Figure 4-2shows a comparison of the Cisco compression solutions.
Data Center High Availability Clusters Design Guide
