the normal Ping takes 0.270ms and I believe this is too much
Ah, no. Sorry. It is quite ok.
need very low latency? Use technology designed for that. Infiniband.
Tere is latency in 1gb networks. 0.2ms is less than 1ms. It is ok for 99% of the applications.
So how I can optimize the latency in general, which will help me in .NET WCF also
No, it will not. At the end., a proper designed WCF based cluster system will handle decent latency without problems. Yes, indicidual packes will take longer than zero time, but on the other hand proper message protocol design and work packet granularity in a cluster means that this does not mean machines do nothing.
I do a lot of distributed systems design / operations and seriously, 0.2ms is not somthing I would orry about, unless designing a HFT system, and then using WCF in itself is a stupid move - HFT counds latency in Microseconds tehse days (note: HFT = High Frequency Trading).