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View Full Version : What kind of networkcard


Lmax
12-17-2001, 02:02 PM
What kind of network card would you prefer in your servers?? 3com(expensive but more reliable)
Realtec(cheaper but less reliable)
or others??
And does one have obvious (dis)advantages compared to the other.

bobcares
12-17-2001, 03:21 PM
For servers,
Intel EtherExpress Pro is a lovely card. We use it for our servers and it has worked real well.
On most of the work stations in our office here we use realtek 8139. I do not mind it much. However, once I had come accross the documentation in ther kernel sources for BSD. Given below is the quoted lines... Please note that I have nothing against rtl8139 and I too use it (though not for our servers... ) .....;)


The RealTek 8139 PCI NIC redefines the meaning of 'low end.' This is probably the worst PCI ethernet controller ever made, with the possible exception of the FEAST chip made by SMC. The 8139 supports bus-master DMA, but it has a terrible interface that nullifies any performance gains that bus-master DMA usually offers.
For transmission, the chip offers a series of four TX descriptor registers. Each transmit frame must be in a contiguous buffer, aligned on a longword (32-bit) boundary. This means we almost always have to do mbuf copies in order to transmit a frame, except in the unlikely case where a) the packet fits into a single mbuf, and b) the packet is 32-bit aligned within the mbuf's data area. The presence of only four descriptor registers means that we can never have more than four packets queued for transmission at any one time. Reception is not much better. The driver has to allocate a single large buffer area (up to 64K in size) into which the chip will DMA received frames. Because we don't know where within this region received packets will begin or end, we have no choice but to copy data from the buffer area into mbufs in order to pass the packets up to the higher protocol levels.

It's impossible given this rotten design to really achieve decent performance at 100Mbps, unless you happen to have a 400Mhz PII or some equally overmuscled CPU to drive it.
On the bright side, the 8139 does have a built-in PHY, although rather than using an MDIO serial interface like most other NICs, the PHY registers are directly accessible through the 8139's register space. The 8139 supports autonegotiation, as well as a 64-bit multicast filter.

The 8129 chip is an older version of the 8139 that uses an external PHY chip. The 8129 has a serial MDIO interface for accessing the MII where the 8139 lets you directly access the on-board PHY registers. We need to select which interface to use depending on the chip type.



I hope you found this interesting. ... :)

Have a great day :)

regards
amar

RackMy.com
12-17-2001, 03:22 PM
For servers, Intel Pro 100+ Server adapters are really fast and reliable. If you don't need the security encryption, the Desktop model also works very well.

Lmax
12-17-2001, 03:34 PM
Forgot to mention intel in the poll, stupid of me ;)