Hello Didier, I understand why you avoid the header compression, the problem is if one is running an encryption application, etc it is difficult to compress he payload. If for example, you create a raw socket then your application is able to write the headers and also compress it. I have a bit of a problem getting my head around memcopy, and on that is it possible to use a framework such as Netmap which is way much efficient in the IO, What I am thinking of is to create ROHC as a device driver in that respect. You can then use mmap system call instead of memcopy to map ROHC device memory directly into a user process's address space. I am not a programmer but I think it's more efficient to use kernel kiobuf implement DMA raw I/O. Just my thoughts. Cheers, Abdul Hakeem
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Didier Barvaux Sent: Wednesday, March 13, 2013 8:01 PM To: [email protected] Subject: Re: [Rohc] ROHC for an Ethernet Link Hi, > I am trying to write a custom code for an InterSwitch Link (ISL), can > you please advise how I can compress the headers > of all the Ethernet frames that goes through the link between the two > Layer 2 switches ?. > The ISL is just a simplified bridge. The ROHC protocol does not compress the Ethernet header itself, so for better efficiency you should leave the Ethernet header unchanged, and compress the Ethernet payload with the ROHC library. In short: a/ skip the Ethernet header, b/ compress the Ethernet payload (possibly IPv4 or IPv6) with the ROHC library, c/ copy the Ethernet header you skipped before the ROHC packet so that your compressed packet can be handled by the Ethernet network. You may find an example within the non-regression test of the library. The non-regression test gets an Ethernet packet from a capture file, skips its header, compresses its payload, adds back the header, then writes the resulting frame to a another capture file. See http://bazaar.launchpad.net/~didier-barvaux/rohc/main/view/head:/test/non_regres sion/test_non_regression.c#L451 I hope I was clear enough. If not, tell me. Regards, Didier _______________________________________________ Mailing list: https://launchpad.net/~rohc Post to : [email protected] Unsubscribe : https://launchpad.net/~rohc More help : https://help.launchpad.net/ListHelp
