Hello Detlev, DH> I read very often, it is better for the perfomance to disallow DH> autonegociation. It might be "better" to reduce lags at link-up events, but since autoneg takes under a second, this bonus can usually be disregarded.
What's usually more noticeable is the 15- or 30-second lag due to spanning-tree protocol (STP). It checks at link-up event whether you have ethernet loops (i.e. the newly-up device is a hub), because the standard Ethernet topology is a star, and STP disables the least-priority port in the loop (if there is one). This allows to have redundant physical links while not breaking classic ethernet logic (link-aggregation is usually better, though). For example, recent Cisco Catalyst switches have spanning-tree checks enabled by default. This often causes DHCP-boot timeouts (the client gives up before the port actually begins transmitting). For this reason STP can be disabled on per-port basis by: spanning-tree portfast trunk or spanning-tree portfast depending on the link's switchport mode (VLAN trunk or access mode). It's meant to be disabled only on the ports which are known to be end-user devices and nobody would plug a hub or switch into a couple of these "portfast" ports. If you do use manual speed/duplex settings instead of autonegotiation, make sure both sides use the same settings, otherwise expect the autoneg device to drop down to half-duplex - as per standard. This can usually be noticed as the connection still works, but is very lossy and slow (local downloads run at approx 1Mbps on 100Mbps network). In fact, half-duplex settings (either manual or due to autonegotiation vs fixed settings) can be used in short term to work around broken NICs or cables. We had some cables chewed by mice or stamped by heavy furniture in the university campus network I managed. While it was not always quick to lay down new cable (because of manual-negotiating with the hostel management ;) ), it was often helpful to re-crimp RJ45 jacks and perhaps revert to half-duplex if only 2 wires of the cable remain intact. -- Best regards, Jim Klimov mailto:[EMAIL PROTECTED] _______________________________________________ SunRay-Users mailing list [email protected] http://www.filibeto.org/mailman/listinfo/sunray-users
