On Fri, 29 Mar 2002, Sam Ewing wrote: > Thank Constin,that really helped. Are there any > advantages of WARP over APJ? I mean why would I want > to use one over the other?
I have no idea :-) If you care how strings and ints are encoded, or what's the packet structure probably you would pick one. I don't like either - the only reason I use ajp13 is backward compatibility and the fact that all versions of tomcat supports it. Ok, the history is a bit complicated, it started with ajp11 and ajp12 ( first text based, second binary ). Ajp12 evolved into ajp13 - using same encoding but with some extensions ( to deal with persistent connections ). Looking back - and forward - I think using CDR or XDR would have been ( or will be ) much better choices for marshalling, and a subset of RPC or IIOP for protocol. Jk2 supports multiple protocols, and one of the reasons is to allow a future migration to a more standard protocol. We're not the only one inventing protocols - look at DCOP :-) And it seems full IIOP ( or at least using an existing ORB ) does have performance impact, or did for KDE people. Plus it would not easily allow the kind of transports we are using or want to use ( unix sockets, JNI, doors, etc ). However using a minimal subset ( we only deal with strings, ints, arrays of string and very simple method calls ) would eliminate most of the confusion and maybe even provide more interoperability. Anyway - ajp13 is here to stay - but I hope it'll be the last binary protocol we invent for jk. Costin > > Sam > > --- [EMAIL PROTECTED] wrote: > > On Thu, 28 Mar 2002 [EMAIL PROTECTED] wrote: > > > > > Maybe I've not kept up on the docs enough but ... > > > > > > I do think this thread, highlights a general > > confusion around tomcat. > > > Over the last couple of years, there have been > > many > > > mod_jk/jk2/webapp/warp/?? implementations, ajp > > versions etc, and even > > > when the discussions are on the list, it's still > > hard to be able to say > > > (for lowly thread lurkers/tomcat users like > > myself), tomcat X.x can use > > > mod_??, on ajp?.? because they provide xyz.. > > > > The problem is I have no time and I'm not good at > > writing docs. > > > > Mod_jk works on all web servers and with all tomcat > > versions. Mod_jk2 > > will do the same. > > > > The core of the confusion is the distinction between > > "protocol", "API", > > "implementation". > > > > A protocol is something like IIOP, RPC, HTTP. The > > API is a set of > > functions - for forwarding the request, getting > > response, config, auth, > > etc. > > > > Mod_jk is an implementation that supports multiple > > communication > > protocols and multiple APIs. Different versions of > > tomcat also support > > multiple protocols and APIs. > > > > There are 4 protocols we use: > > - ajp12 ( in tomcat3.x, jserv ) > > - ajp13 ( in tomcat3.x, tomcat4.x ) > > - jni ( in tomcat3.x - and 4.x as soon as jk2 is > > ready ) > > - WARP ( in tomcat4.x ) > > > > There are several APIs: > > - request forwarding APIs - usually one method > > signature for each protocol > > - configuration methods - in warp and what used to > > be called ajp14 ( very > > confusing, since it was a set of new methods > > implemented with ajp13 > > protocol ) > > - auth, shutdown, etc - again 2 or 3 if you count > > the 4.0 shutdown > > protocol. > > > > And several implementations of those protocols: > > - mod_jserv implements ajp12 > > - mod_jk implements ajp12, ajp13, jni > > - mod_jk2 implements ajp13 ( and one of my goals for > > a future version is > > to implement one 'real' protocol - a minimal subset > > of RPC/XDR or IIOP or > > similar ) ( with jni replaced with ajp13 - and > > multiple channels - tcp, > > unix, jni ) > > - mod_webapp implements WARP > > - tomcat3.x implements ajp12, ajp13, jni > > - tomcat4.x - ajp13, WARP > > > > And several implementations of the APIs ( similar > > matrix ). The basic > > request forwarding APIs used in jk is common to all > > servers and should be > > fully interoperable. Extended APIs ( config, etc) > > are supported only in > > new versions of tomcat/jk. > > > > Load balancing is one extra feature in mod_jk and > > mod_jserv, on top of the > > forwarding API. > > > > > > > > Costin > > > > > > -- > > To unsubscribe, e-mail: > > <mailto:[EMAIL PROTECTED]> > > For additional commands, e-mail: > > <mailto:[EMAIL PROTECTED]> > > > > > __________________________________________________ > Do You Yahoo!? > Yahoo! Greetings - send holiday greetings for Easter, Passover > http://greetings.yahoo.com/ > > -- > To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> > For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> > -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
