RE: HTTP over SCTP
-Original Message- From: Paul Querna [mailto:p...@querna.org] Sent: Tuesday, March 31, 2009 4:54 PM To: dev@httpd.apache.org Cc: d...@apr.apache.org; Jonathan Leighton; Preethi Natarajan (prenatar) Subject: Re: HTTP over SCTP Please post the patches, preferablly against trunk: http://httpd.apache.org/dev/patches.html Once we see the patches we will be in a much better position to give feedback, Paul, Sometime ago, we were directed to do the same. You can find a report (and patch) here -- https://issues.apache.org/bugzilla/show_bug.cgi?id=37202. Breifly, the mods to httpd/APR are: - new Listen directive to include the transport information (I believe this piece created some discussion and we didn't arrive at any conclusion). - changes to configure files to detect sendmsg and recvmsg in the system to send/recv on specific SCTP streams. We would also like to explore the possibility of introducing new send and recv APIs that can have the SCTP stream ID as another argument -- kind of wrappers for sctp_sendmsg and sctp_recvmsg. Thanks, Preethi
HTTP over SCTP
Hello folks, We are trying to adapt HTTP to work over SCTP streams (http://tools.ietf.org/html/draft-natarajan-http-over-sctp-01). Since this proposal was received warmly at the httpbis WG, we are contemplating on a more formal specification of HTTP over SCTP. The current HTTP over SCTP design exploits SCTP streams to avoid head-of-line blocking. SCTP also offers other services unavailable in TCP such as unordered delivery, partially reliable transmission, message based transfer, multihoming support, more secure connection establishment with a cookie mechanism and so on. We plan on adapting our design proposal to leverage some/all of these SCTP services in the future. We implemented HTTP over SCTP streams in Apache and Firefox. Experiments show significant improvements to end user performance in networks with high latency and/or lossy paths. (I can point you to relevant material if you are interested in knowing more.) We are interested in submitting our code changes to APR and httpd. We'd very much appreciate guidance from httpd and APR developers on our mods and the submission process. Thanks! Preethi
Re: Apache with SCTP streams.
On Tue, 25 Oct 2005, Ruediger Pluem wrote: As Joe mentioned in its bugzilla comment, these changes must be done to the trunk first. So I would propose the following approach: 1. Provide your httpd part of the patch as a patch against trunk. 2. For the apr part of the patch I would suggest that you check if there is a released version of apr which handles your requirements without further patches. If there is no such released version of apr I guess the next step depends: If there is a version which should work (provides all features that you need) but actually does not work, I would regard this as a bug that should be fixed in this apr branch. So you should file an apr bug report including the fix patch. If you find no apr version that contains the features you need, I guess the apr patches should be also done against the trunk. I guess this would also require further discussion on the apr dev list. I discussed with APR developers list and : 1. I will patch my changes to APR against the main APR trunk. 2. Given that, I will patch changes to httpd against the trunk. Hope this is fine. Let me know if otherwise, Preethi
Apache using SCTP streams
Hello, I've been working on this patch to make apr and httpd work with SCTP streams. Stream Control Transmission Protocol (SCTP - RFC2960) is a transport layer protocol capable of providing reliable (in-order, no loss, no duplicates, no error) message oriented service to application. Other interesting features of SCTP include multistreaming (many logical pipes in 1 SCTP association to transfer independent data like web objects without head of line blocking problem) and multihoming (ability to support more than 1 interface/IP address at a SCTP endpoint). The idea was to enable httpd to receive HTTP request on a particular SCTP stream and send the HTTP response on the same stream. Using different SCTP streams for independent objects might improve performance (preventing HOL as mentioned above). To give an outline of the implementation with the files involved: o I created apr_socket_send_sctp and apr_socket_recv_sctp which take an extra parameter - SCTP stream id. The recv function uses recvmsg function call and gets the SCTP stream id on which the request came in. Similarly, sendmsg call is used in apr_socket_send_sctp (sendrecv.c in network_io/unix). o I didnt want to change the signature of any other function so I decided to use buckets to pass the stream id info to and fro. The socket bucket read puts the stream id (from recv) in a heap bucket and the caller takes the responsibility of retrieving this. (apr_buckets_socket.c, apr_brigade.c, core_input_filter - core.c). o core_input_filter stores the stream id in a field in the core_net_rec, which is used by core_output_filter while sending response. o Also, I changed Listen directive to take the transport layer protocol as an extra argument so that web admin can choose SCTP or TCP. Currently, I have this patch working for httpd-2.0.55/apr-0.9.6. Would appreciate any feedback, Preethi
Apache with SCTP streams.
Hello, I've been working on this patch to make apr and httpd work with SCTP streams. Stream Control Transmission Protocol (SCTP - RFC2960) is a transport layer protocol capable of providing reliable (in-order, no loss, no duplicates, no error) message oriented service to application. Other interesting features of SCTP include multistreaming (many logical pipes in 1 SCTP association to transfer independent data like web objects without head of line blocking problem) and multihoming (ability to support more than 1 interface/IP address at a SCTP endpoint). The idea was to enable httpd to receive HTTP request on a particular SCTP stream and send the HTTP response on the same stream. Using different SCTP streams for independent objects might improve performance (preventing HOL as mentioned above). apr-0.9.2 included recognition and support for SCTP from Randall Stewart. I did my changes on top of this. To give an outline of the implementation with the files involved: APR: o I created apr_socket_send_sctp and apr_socket_recv_sctp which take an extra parameter - SCTP stream id. The recv function uses recvmsg function call and gets the SCTP stream id on which the request came in. Similarly, sendmsg call is used in apr_socket_send_sctp (sendrecv.c in network_io/unix). o I didnt want to change the signature of any other function so I decided to use buckets to pass the stream id info to and fro. The socket bucket read puts the stream id (from socket recv) in a heap bucket and the caller takes the responsibility of retrieving this. (apr_buckets_socket.c, apr_brigade.c). HTTPD: o core_input_filter retrieves and stores the stream id in a field in the core_net_rec, which is used by core_output_filter-APR while sending response. o Also, I changed Listen directive to take the transport layer protocol as an extra argument so that web admin can choose SCTP or TCP. Currently, I have this patch working for httpd-2.0.55/apr-0.9.6. Would appreciate any feedback, Preethi PS: Should I send this mail to apr dev mailing list as well or will that be spamming?
