I don't have Lab5 yet but based on the info you have provided here is my $0.02.
If you are given 172.16.69.0/30 you have the following ip addresses; 172.16.69.0/30 - network address (not usable) 172.16.69.1/30 - first available ip address 172.16.69.2/30 - second and last available ip address 172.16.69.3/30 - broadcast address (not usable either) If you have two separate point-to-point links that need to be configured you have at least two options: 1.- Configure MLPPP and assign .1 to R6 and .2 to R9 2.- Split the /30 into two /31's From what you have stated, the solution given used option 2. I don't think your config will work (but I could be wrong) since you will have two L3 interfaces on the same router in the same network range. Also, read about the "ip classless" command. HTH, Rogelio On Dec 29, 2009, at 8:24 PM, Bauke Dzavhale wrote: > Team, > > Can someone help clarify the ip add assignment on R6 and R9, Task 2-2 LAB5- > Vol2 DSG? > > We are give the subnet 172.16.69.0/30 to be used and we have 4 interfaces > (s0/2/0, s0/2/1) on both R6 and R9. > This is my understanding: > > 1- The subnet gives us 4 ip addresses: 172.16.69.0, 172.16.69.1, 172.16.69.2, > 172.16.69.3, with .0 and .3 being subnet and broadcast address > respectively. > > There is 2 approaches here: > a) If I did not have the restriction to use /30 subnet, I would open up the > range and I would use a /29 subnet, which would give me enough [6 usable] ip > addresses to assign to my 4 interfaces. > b) Since I have the /30 restriction in place I will use the 4 ip addresses > indicated above for my 4 serial interfaces [provided ip classless is in > place], and this allows me to do the following: > > In R6: > int s0/2/0 > ip add 172.16.69.0 255.255.255.252 > > int s0/2/1 > ip add 172.16.69.2 255.255.255.252 > > > In R9: > int s0/2/0 > ip add 172.16.69.1 255.255.255.252 > > int s0/2/1 > ip add 172.16.69.3 255.255.255.252 > > The solution assigns the same ip add [172.16.69.0 255.255.255.254] to both > s0/2/0 and s0/2/1 on R6, and the remaining (.1 and .3 ) are assigned to R9. > > My obvious question are: > - Can we do this on R6? The .2 has not even been used but s0/2/0 and s0/2/1 > share the same ip add [.0] on R6.... > - Why change the mask to 255.255.255.254 (/31) ? The requirement is to use > /30. > > > Thanks > > B. > > All new Yahoo! Mail - Get a sneak peak at messages with a handy reading > pane._______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com
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