[Tinyos-2-commits] CVS: tinyos-2.x/doc/txt tep123.txt,1.10,1.11

[Omprakash Gnawali]

Update of /cvsroot/tinyos/tinyos-2.x/doc/txt
In directory ddv4jf1.ch3.sourceforge.com:/tmp/cvs-serv21068

Modified Files:
	tep123.txt 
Log Message:
Razvans comments

Index: tep123.txt
===================================================================
RCS file: /cvsroot/tinyos/tinyos-2.x/doc/txt/tep123.txt,v
retrieving revision 1.10
retrieving revision 1.11
diff -C2 -d -r1.10 -r1.11
*** tep123.txt	14 Dec 2007 20:09:39 -0000	1.10
--- tep123.txt	21 Nov 2008 01:05:50 -0000	1.11
***************
*** 32,35 ****
--- 32,47 ----
  ==============================================================================
  
+ A collection protocol delivers data to one of possibly several data
+ sinks, providing a many-to-one network layer. Collection is a
+ fundamental component of most sensor network applications. The
+ Collection Tree Protocol (CTP) is a reference Collection protocol in
+ TinyOS 2.x. The users use Collection interfaces described in TEP 119
+ [3]_ to use CTP in their applications.
+ 
+ In this TEP, after a brief discussion of Collection and CTP, we
+ specify the CTP routing and data frames. CTP uses routing frames to
+ update and build collection tree in the network. CTP uses data frames
+ to deliver application payload to the sink.
+ 
  2. Assumptions and Limitations
  ==============================================================================
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*** 94,104 ****
  
  Packet duplication is an additional problem that can occur in CTP.
! Packet duplication occurs when a node receives a data frame successfully
! and transmits an ACK, but the ACK is not received. The sender retransmits
! the packet, and the receiver receives it a second time. This can have
! disasterous effects over multiple hops, as the duplication is exponential.
! For example, if each hop on average produces one duplicate, then on the
! first hop there will be two packets, on the second there will be four,
! on the third there will be eight, etc.
  
  Routing loops complicate duplicate suppression, as a routing loop may
--- 106,120 ----
  
  Packet duplication is an additional problem that can occur in CTP.
! Packet duplication occurs when a node receives a data frame
! successfully and transmits an ACK, but the ACK is not received. The
! sender retransmits the packet, and the receiver receives it a second
! time. This can have disasterous effects over multiple hops, as the
! duplication is exponential.  For example, if each hop on average
! produces one duplicate, then on the first hop there will be two
! packets, on the second there will be four, on the third there will be
! eight, etc. CTP keeps a small cache of packet signature for the
! packets it has seen to detect packet duplicates. When a new packet
! arrives, if its signature results in cache hit, CTP drops the packet
! because it is a duplicate.
  
  Routing loops complicate duplicate suppression, as a routing loop may
***************
*** 132,136 ****
  Field definitions are as follows:
  
!   * P: Routing pull. The P bit allows nodes to request routing information from other nodes. If a node with a valid route hears a packet with the P bit set, it SHOULD transmit a routing frame in the near future.
    * C: Congestion notification. If a node drops a CTP data frame, it MUST set the C field on the next data frame it transmits.
    * THL: Time Has Lived. When a node generates a CTP data frame, it MUST set THL to 0. When a node receives a CTP data frame, it MUST increment the THL. If a node receives a THL of 255, it increments it to 0.
--- 148,152 ----
  Field definitions are as follows:
  
!   * P: Routing pull. The P bit allows nodes to request routing information from other nodes. If a node with a valid route hears a packet with the P bit set, it SHOULD transmit a routing frame in the near future. Data frames are unicast so only the destination of the unicast transmission responds to the P bit in the data frame.
    * C: Congestion notification. If a node drops a CTP data frame, it MUST set the C field on the next data frame it transmits.
    * THL: Time Has Lived. When a node generates a CTP data frame, it MUST set THL to 0. When a node receives a CTP data frame, it MUST increment the THL. If a node receives a THL of 255, it increments it to 0.
***************
*** 171,175 ****
  The fields are as follows:
    
!   * P: Same as data frame.
    * C: Congestion notification. If a node drops a CTP data frame, it MUST set the C field on the next routing frame it transmits.
    * parent: The node's current parent.
--- 187,191 ----
  The fields are as follows:
    
!   * P: Same as data frame with one difference: Routing frames are broadcast so multiple nodes respond to the P bit in the routing frame.
    * C: Congestion notification. If a node drops a CTP data frame, it MUST set the C field on the next routing frame it transmits.
    * parent: The node's current parent.
***************
*** 186,189 ****
--- 202,207 ----
  future.
  
+ A node MUST send CTP routing frames as broadcast messages.
+ 
  6. Implementation
  ==============================================================================
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*** 342,347 ****
         in Wireless Sensor Networks." In Proceedings of the First USENIX
         Conference on Networked Systems Design and Implementation (NSDI), 2004.
!        
!  
! 
! 
--- 360,362 ----
         in Wireless Sensor Networks." In Proceedings of the First USENIX
         Conference on Networked Systems Design and Implementation (NSDI), 2004.
! .. [3] TEP 119: Collection.