Synchronous Compression

Using Van Jacobson TCP/IP header compression on high-speed synchronous lines is not recommended, because---unlike Stac compression---it degrades performance. Stac compression is available on the Office Routers (OR-U, OR-HS, OR-LS) and on all PortMaster 3's, but not on the PortMaster 2R, 2ER, and the IRX routers.

ON

Compression is enabled. The PortMaster tries to negotiate both Van Jacobson and Stac LZS compression.

OFF

Compression is disabled.

STAC

Stac LZS data compression alone is enabled.

VJ

Van Jacobson TCP/IP header compression only is enabled.