Changes between Version 26 and Version 27 of Internal/StudentPages/XiruoLiu

Timestamp:

Jun 11, 2012, 2:41:40 PM (12 years ago)

Author:

sissiok

Comment:

--

Internal/StudentPages/XiruoLiu

@@ -89 +89 @@
 
 4. Delivery failure due to node moving [[BR]] 
-Assume traffic is from service provider's static server C to mobile node D. [[BR]] 
-(1) While generating updates, check node D every minute; therefore, in simulation, the gap between update events is multiple minutes. [[BR]] 
-(2) The routing delay of packets transmission from C to D depends on the routing infrastructure, link quality and status, routing strategy used, etc. For simplicity, assume this delay T3 is some constant. [[BR]] 
+Assume traffic is from service provider's static server C to mobile node D, router E is D's original grid router, router F is D's new grid router after move. [[BR]] 
+(1) While generating updates, check node D every minute to see whether an update need to be generated. Therefore the gap between update events is multiple minutes. After receiving an packet successfully from service server, mobile node will reply an ACK to the server. Therefore, in simulation, two scenarios are possible: a) Move after ACK: D replies an ACK and then move to another grid, delivery of the next packet from C will fail due to the move. b) Move before ACK: D moves to another grid while receiving a packet, so the transmission of the packet will terminate and router E will send query to its GNRS server. As a result, the delay for discovering delivery failure is determined by the transmission mechanism.  [[BR]] 
+(2) The routing delay of packets transmission from C to E depends on the routing infrastructure, link quality and status, routing strategy used, etc. For simplicity, assume this delay T3 is some constant. [[BR]] 
 (3) Packets, which are sent from C to router E (D's original grid router) during the update latency period T1, can not be delivered to D successfully. E holds the packets and queries C's binding every T4 seconds (T4 > T2).  Latency in this stage is T5 = T2 + (k-1)T4 (k is the times of E's query ). [[BR]] 
-(4) Packet then reroute from router E to router F (D's new grid router). This delay T6 can simply set to proportion to the distance between E and F. [[BR]] 
+(4) Packet then reroute from router E to router F (D's new grid router). This delay T6 can simply set to proportion to the distance between E and F as in (2). [[BR]] 
 
        latency due to delivery failure <= T1 + T5 + T6       ("<" is possible when D sends out update and C's router sends out query for D at the same time, in this case T1 and T2 have overlap) [[BR]] [[BR]]