Re: Multicast filtering
Donald Becker <[email protected]>
| Newsgroups | gmane.linux.drivers.realtek.devel |
|---|---|
| Message-ID | <Pine.LNX.4.33.0206031508290.1329-100000@presario> |
On Thu, 30 May 2002, Karthik Thirumalai wrote: > I am running redhat 7.x and using the rtl8139 driver which came in the > package. Are you using 'rtl8139' or the '8139too' driver? What is the version number of the driver? > I am having trouble with the multicast filtering. My card does not seem do > any filtering (i check this with a tcpdump). The scyld website says that > 8139 supports multicast filtering. It does, using a 64 bin filter based on the upper six bits of the Ethernet CRC. The 'rtl8139' driver uses this hardware to filter multicast reception. The only user-tunable setting is a module parameter named 'multicast_filter_limit' with a default value of 32. The driver switches to rx-all-multicast mode when more than 32 hardware multicast addresses are accepted. This avoids the driver recomputing and reloading the filter with a large (and presumably frequently-changing) multicast-accept list. The '8139too' driver started from my driver code, but I don't track what changes are made to it. > My recv uses 225.0.0.37 port 6400. Keep in mind that IP multicast addresses are over-mapped to Ethernet multicast addresses. Multiple IP multicast addresses end up on a single Ethernet multicast address. (Grrrr, all for political/control reasons. With 47 bits it wasn't like there was a shortage of Ethernet address bits.) -- Donald Becker [email protected] Scyld Computing Corporation http://www.scyld.com 410 Severn Ave. Suite 210 Second Generation Beowulf Clusters Annapolis MD 21403 410-990-9993