Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757500AbbDVQ4S (ORCPT ); Wed, 22 Apr 2015 12:56:18 -0400 Received: from alln-iport-5.cisco.com ([173.37.142.92]:13027 "EHLO alln-iport-5.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757470AbbDVQ4P convert rfc822-to-8bit (ORCPT ); Wed, 22 Apr 2015 12:56:15 -0400 X-Greylist: delayed 579 seconds by postgrey-1.27 at vger.kernel.org; Wed, 22 Apr 2015 12:56:15 EDT X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: A0BcBACezzdV/49dJa1bgwyBLgXGAwmHUwKBODgUAQEBAQEBAYEKhCEBAQMBOj8FCwIBCDYQMiUCBA4FiCMIzHoBAQEBAQEBAQEBAQEBAQEBAQEBAQEXizeBT4MCMweDF4EWAQSGNYsGiiqVMSKDc2+BRIEAAQEB X-IronPort-AV: E=Sophos;i="5.11,624,1422921600"; d="scan'208";a="143586922" From: "Dave Goodell (dgoodell)" To: Liran Liss CC: Michael Wang , Roland Dreier , Sean Hefty , Hal Rosenstock , "linux-rdma@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "hal@dev.mellanox.co.il" , Tom Tucker , Steve Wise , Hoang-Nam Nguyen , "raisch@de.ibm.com" , Mike Marciniszyn , Eli Cohen , Faisal Latif , Jack Morgenstein , "Or Gerlitz" , Haggai Eran , "Ira Weiny" , Tom Talpey , Jason Gunthorpe , Doug Ledford Subject: Re: [PATCH v5 00/27] IB/Verbs: IB Management Helpers Thread-Topic: [PATCH v5 00/27] IB/Verbs: IB Management Helpers Thread-Index: AQHQe0QU1mp+1oZpFEK4Xo8V6OKflZ1YdVEAgAEfwoA= Date: Wed, 22 Apr 2015 16:46:34 +0000 Message-ID: <2AA673EC-CC51-4E3B-BAF1-88B40D8CABB4@cisco.com> References: <5534B8C9.506@profitbricks.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.27.35.215] Content-Type: text/plain; charset="us-ascii" Content-ID: <1863CF9D95D5DB42AB2D70E9101C852A@emea.cisco.com> Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1689 Lines: 31 On Apr 21, 2015, at 6:36 PM, Liran Liss wrote: > An ib_dev (or a port of) should be distinguished by 3 qualifiers: > - The link layer: > -- Ethernet (shared by iWARP, USNIC, and ROCE) > -- Infiniband > > - The transport (*) > -- IBTA transport (shared by IB and ROCE) > -- iWARP transport > -- USNIC transport I haven't been following this discussion as closely as I could have, but I want to clarify something about usNIC. There are two "transports" used by usNIC: 1. The legacy RDMA_TRANSPORT_USNIC type, which indicates usNIC traffic will be Ethernet frames with Ethertype==0x8915 (like RoCE) but containing a custom, non-IBTA-sanctioned header format instead of a full GRH. This "transport" is still supported by the usnic_verbs kernel driver but in practice is no longer in use. For this "transport" there isn't really any clear L3/L4 header to point to. 2. The current RDMA_TRANSPORT_USNIC_UDP type, which indicates usNIC traffic will be standard UDP/IP/Ethernet packets. > (*) Transport means both: > - The L4 wire protocols (e.g., BTH+ headers of IBTA, optionally encapsulated by UDP in ROCEv2, or the iWARP stack) > - The transport semantics (for example, there are slight semantic differences between IBTA and iWARP) No usNIC hardware or software currently performs any hardware offload of RDMA features (only UD is supported), so there is no usNIC equivalent of the BTH+ to discuss right now. -Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/