Snapshots

1. Load Balancing Section of dlbDNS

A. Request for bestlinux.cs.twsu.edu.

ENTERING LOAD BALANCING SECTION
List of servers for bestlinux
0: sisko.cs.twsu.edu
1: kira.cs.twsu.edu
Return/Total : 1/2
Return/Total : 2/2
sisko.cs.twsu.edu       4735
kira.cs.twsu.edu        3580
BestPosition/BestHost : 1/kira.cs.twsu.edu
LEAVING LOAD BALANCING SECTION
Here, kira.cs.twsu.edu has a lesser rating than sisko.cs.twsu.edu, so kira.cs.twsu.edu is returned as the best server to the client.

B. Request for www2.cs.twsu.edu with one of the servers having an optimal rating.

ENTERING LOAD BALANCING SECTION
List of servers for www2
0: q.cs.twsu.edu
1: daneel.cs.twsu.edu
2: giskard.cs.twsu.edu
3: sisko.cs.twsu.edu
4: kira.cs.twsu.edu
Received Best Rating
daneel.cs.twsu.edu      400
BestPosition/BestHost : 1/daneel.cs.twsu.edu
LEAVING LOAD BALANCING SECTION
Here, daneel.cs.twsu.edu has a rating less than the optimal rating of 1500, so dlbDNS returns back daneel.cs.twsu.edu as the best server to the client without waiting for the other servers to return their ratings.

C. Request for www1.cs.twsu.edu with only two of the four servers responding.

ENTERING LOAD BALANCING SECTION
List of servers for www1
0: sisko.cs.twsu.edu
1: kira.cs.twsu.edu
2: daneel.cs.twsu.edu
3: giskard.cs.twsu.edu
Return/Total : 2/4
Return/Total : 2/4
Return/Total : 2/4
Return/Total : 2/4
Return/Total : 2/4
*** Time elapsed for waiting ***
sisko.cs.twsu.edu       4774
kira.cs.twsu.edu        3610
daneel.cs.twsu.edu      10000
giskard.cs.twsu.edu     10000
BestPosition/BestHost : 1/kira.cs.twsu.edu
LEAVING LOAD BALANCING SECTION
The dlbDNS waits a specific period of time for the servers to return their rating. If the servers fail to return in this time period, dlbDNS gives the server a maximum rating of 10000. Here, daneel.cs.twsu.edu and giskard.cs.twsu.edu fail to respond within the specific time period, so dlbDNS assigns them a maximum rating of 10000.

2. Rating Demon

Request from dlbDNS
Rating returned to dlbDNS : 4762
Sun Dec 13 17:34:58 CST 1998
Updated Rating       : 4735
Request from dlbDNS
Rating returned to dlbDNS : 4735
Request from dlbDNS
Rating returned to dlbDNS : 4735
Sun Dec 13 17:35:58 CST 1998
Updated Rating       : 4795
Sun Dec 13 17:36:58 CST 1998
Updated Rating       : 4774
Request from dlbDNS
Rating returned to dlbDNS : 4774
Request from dlbDNS
Rating returned to dlbDNS : 4774
Sun Dec 13 17:37:58 CST 1998
Updated Rating       : 4771
Sun Dec 13 17:38:58 CST 1998
Updated Rating       : 4653
Sun Dec 13 17:39:59 CST 1998
Updated Rating       : 4629
Sun Dec 13 17:40:59 CST 1998
Updated Rating       : 4691
Sun Dec 13 17:41:59 CST 1998
Here, the rating demon updates its rating once every minute independent of dlbDNS request. When there is a request for rating from dlbDNS, the rating demon replies by returning the latest rating of the server rather than calculating the rating again.