3Com Router 3000 Ethernet FamilyConfiguration Guide Chapter 1 PPP and MP Configuration3Com Corporation1-241.4.2 Configuring PPP Stac LZS CompressionPerform the following configuration in interface view.The current system version supports the Stac compression described in RFC 1974.Table 1-31 Configure PPP Stac LZS compressionOperation CommandEnable Stac LZS compression on theinterface. ppp compression stac-lzsDisable Stac LZS compression on theinterface. undo ppp compression stac-lzsBy default, compression is disabled.1.4.3 Configuring VJ TCP Header Compression for PPP PacketsPerform the following configuration in interface view.Table 1-32 Configure VJ TCP header compressionOperation CommandEnable VJ TCP header compression onthe PPP interface. ip tcp vjcompressDisable VJ TCP header compression onthe PPP interface. undo ip tcp vjcompressBy default, VJ TCP header compression is disabled on the PPP interface.1.4.4 Configuring Link Fragmentation and Interleaving on PPPThe real-time interactive communication may be congested and delayed because oflarge packets on the low-speed serial link. For example, the voice packet arrives whilethe large packet is being dispatched and waiting for transmission, it can only bedispatched upon the completion of the large packet transmission; thus, delay occurs.For the real-time reference programs such as the interacting voice, congestion delayresulted from large packet is too long. Link Fragment and Interleave (LFI) divides thelarge data frame into small frames and then transmits them to the front of thetransmission queue and inserts the small packets that are sensitive to delay betweenthe fragments. In this way, the delay of small real-time packet is reduced andfragments can be reassembled at the destination.The LFI configuration tasks are described in the following subsections:z Enabling LFIz Configuring maximum time delay of LFI fragments
