Unfortunately we can't really recommend specific models of switches or routers to work with Ghost, but the 3Com 3870 certainly does have an impressive feature set. Although it isn't a full Layer 3 switch, the data sheets indicate it does have the necessary IGMPv2 snooping and query generation which should in principle make it a capable multicast performer.
Probably the main issue I have heard of in dealing with switch and router selection is that some people do have problems when mixing vendors because of slight differences in the implementations of the newer control protocols. As long as the 3Com units stack as widely as you need that shouldn't be an issue.
> Will using multiple or dual core processors have any performance benefit for any Ghost or unicasting functions?
Although it's conceivable that they could in future help with CPU-intensive data compression operations during image capture, at present Ghost isn't written to take particular advantage of such features. The image compression is performed only at the client end at present, not at the server. The corresponding decompression operations are performed at the client end when distributing compressed images, and they are not very CPU-intensive so I would expect relatively little benefit to be found in that case.
In most circumstances, performance of image distribution operations in 100Mbps networks is constrained by the network bandwidth, while in 1Gbps networks the limiting factor is generally the write throughput of the disks in the client machines (which is, with SATA 2 disks in particular, generally rather lower than the headline data rate of the SATA interconnect).
> I am looking at either a 2 or 4 port link aggregating type of TNIC network card (alacritech.com). for better network performance, anyone have experience with this type of network card?
Not particularly with Ghost at the server end; but in general, once you move from 100Mbps to 1Gb networks, most image distribution operations seem to be primarily controlled by the performance of the disk subsystems at the client ends. CPU load on the server side during GhostCast is something we do look at from time to time, but we haven't heard any reports of it being a specific customer issue.
That said, if you are considering storing the Ghost images for distribution on some form of network storage (for instance, an iSCSI volume) then there may well be an argument for a TOE-type card for the path to the network storage on the server machine. Given that the iSCSI market in particular is rapidly evolving it's hard to make definitive statements about performance issues at all.
The same can be said for the RAID market (especially SATA raid) as well; quite what the "best" storage architecture for the image store on your primary image server is not only hard to say now, but likely to change rapidly as the disks, the controllers and the servers all evolve. The SATA RAID environment is particularly exciting.
Really, the single most important thing to look at is having a 1Gbps path from the server out to all the clients; this is the part you'll have to live with for the longest, but if you're currently running a 100Mbps network it's going to be a substantial improvement. The choice of e.g. network card or RAID engine for the server machine is not going to make the same level of difference to your environment, and until you have the 1Gbps infrastructure in place you won't really be able to tell where the performance bottlenecks on the server side are, and whether your should concentrate your money more on your server storage subsystem. You do have a lot of exciting options for storage, whether it's directly-attached SATA RAID on the server (which is becoming very affordable) or network storage.