Homework #3
Network Layer Fun
1: The subnet’s addresses should be as follows.
101.101.128.0/19
101.101.160.0/19
101.101.192.0/19
101.101.224.0/19
2.1:
Fragment 1,
Header Length = 5 (5 because the length is specified as the number of 4 byte pieces), Total Length = 500 bytes, Identification number = 314 (arbitrary decision)
Flag = 1, Offset = 0.
Fragment 2 = Fragment 1 except that offset = 60.
Fragment3,
Header Length = 5, Total Length = 240 bytes, ID = 314, Flag = 0, Offset = 120.
2.2: The IP module can use the Identification Number to determine which fragments need to be put together. It can use the more fragments bit to determine whether or not there is more data it needs to wait for, and it can use the offset numbers to determine the total amount of data as well as reassemble the data in the correct order.
Change-only table: Bold = chosen node to add to N`, blank = no change since last time.
N’ D/P(u) D/P(v) D/P(w) D/P(y) D/P(z) D/P(a) D/P(b) D/P(c)
X 2,x inf 1,x 4,x inf inf inf Inf
Xw 2,x 7, w
Xwu 5,u 3,u
Xwuy 6,y 5,y 4,y
xwuyc 5,u 5,c
xwuycv 5,c
xwuycvz 5,y
xwuycvzb 6,y
xwuycvzba
N 2,x 5,u 1,x 3,u 5,c 6,y 5,y 4,y
Full Table:
N’ D/P(u) D/P(v) D/P(w) D/P(y) D/P(z) D/P(a) D/P(b) D/P(c)
X 2,x inf 1,x 4,x inf inf inf Inf
Xw 2,x inf 1,x 4,x inf 7, w Inf inf
Xwu 2,x 5,u 1,x 3,u inf 7,w Inf Inf
Xwuy 2,x 5,u 1,x 3,u Inf 6,y 5,y 4,y
xwuyc 2,x 5,u 1,x 3,u 5,c 6,y 5,y 4,y
xwuycv 2,x 5,u 1,x 3,u 5,c 6,y 5,y 4,y
xwuycvz 2,x 5,u 1,x 3,u 5,c 6,y 5,y 4,y
xwuycvzb 2,x 5,u 1,x 3,u 5,c 6,y 5,y 4,y
xwuycvzba 2,x 5,u 1,x 3,u 5,c 6,y 5,y 4,y
N 2,x 5,u 1,x 3,u 5,c 6,y 5,y 4,y
4.1: This is tedious, I’m not sure it’s a necessary evil either.
X table: Y table: W table:
X Y W X Y W X Y W
X 0 4 1 X ? ? ? X ? ? ?
Y ? ? ? Y 4 0 8 Y ? ? ?
W ? ? ? W ? ? ? W 1 8 0
Each node advertises its distance to the others.
Each node updates its costs corresponding to...