CVS update: JGroups/doc/design RELAY.txt

  User: belaban 
  Date: 10/11/11 10:34:23

  Modified:    doc/design RELAY.txt
  Log:
  ns
  
  Revision  Changes    Path
  1.6       +36 -11    JGroups/doc/design/RELAY.txt
  
  Index: RELAY.txt
  ===================================================================
  RCS file: /cvsroot/javagroups/JGroups/doc/design/RELAY.txt,v
  retrieving revision 1.5
  retrieving revision 1.6
  diff -u -r1.5 -r1.6
  --- RELAY.txt	9 Nov 2010 10:40:39 -0000	1.5
  +++ RELAY.txt	11 Nov 2010 10:34:23 -0000	1.6
  @@ -3,7 +3,7 @@
   ========================================
   
   Author: Bela Ban
  -Version: $Id: RELAY.txt,v 1.5 2010/11/09 10:40:39 belaban Exp $
  +Version: $Id: RELAY.txt,v 1.6 2010/11/11 10:34:23 belaban Exp $
   
   This is an enhanced version of DataCenterReplication.txt with the ability to send unicast messages and to provide views
   to the application, which list members of all local clusters.
  @@ -93,13 +93,14 @@
   --------------
   
   RELAY.up(msg):
  -- If not coord or RelayHeader is present: break
  -- If multicast message:
  -  - Create new message M.dst=null, src=msg.src // no headers
  -  - Wrap M and put it on the TCP channel
  -- Else: // unicast
  -  - If hdr == RelayHeader.FORWARD:
  -    - Wrap msg and put it on the TCP channel
  +- If not coord: pass up and break
  +- If RelayHeader present:
  +  - If FORWARD: forward(msg); break
  +  - If DISSEMINATE: pass up and break
  +  - Default: break;
  +- Else:
  +  - If multicast message: forward(msg)
  +  - Pass up
   
   
   RELAY.down(msg):
  @@ -111,9 +112,33 @@
   
   
   Receive message M from TCP channel:
  -- If sender = self: discard
  -- Set M.src=ProxyUUID(self,M.src)
  -- Add a RelayHeader to M
  +- Switch RelayHeader:
  +  - Case FORWARD:
  +    - If sender = self: discard
  +    - Else: unwrap M into M2 and putOnLocalCluster(M2)
  +  - Case VIEW:
  +    // todo
  +
  +
  +
  +forward(msg):
  +- Copy msg to M
  +- Remove all headers from  M
  +- Wrap M into a new message M2
  +- Add RelayHeader.FORWARD to M2
  +- Put M2 onto the TCP channel
  +
  +// TBD: should we leave headers ? They're going to be overwritten anyway when relaying the message
  +
  +
  +putOnLocalCluster(M):
  +- Set M.src=ProxyUUID(local_addr,M.src)
  +- Add a RelayHeader.DISSEMINATE to M
   - Put M on the local channel
   
   
  +
  +Issues:
  +- Do we copy the headers of a message M when M is relayed ? If not, an app won't be able to add their own headers
  +
  +
  
  
  

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