how many instances of "=" are there in:
q: vlsm network design i'm studying for the ccna exam and i want to create a vlsm scheme using ripv2 for the following (ccna practice example):


*

*network connecting 4 different locations

*each switch is fa 0/0 on the router

*every point-to-point serial connection is in the network is class c (192.168.1.0 )

*network 172.20.0.0 for each location

*use the lowest subnet number (zero is allowed)


requirements for each location: 


*

*dallas - 500 hosts

*new york - 2000 hosts

*chicago - 1000 hosts

*la - 2000 hosts


here's my design so far:

do you see any flaws in this? how would you fix them? or how would you design this?

a: it looks like you're asking us to do your homework... anyway, i do see some flaws in the subnetting. 
do you really understand how subnetting works ? it doesn't seem so. 
this post may help you to get the picture, but let's improve your design & skills: 


*

*dallas : 500 hosts => 512 => /23

*new york : 2000 hosts => 2048 => /21

*chicago : 1000 hosts => 1024 => /22

*la : 2000 hosts => 2048 => /21


on this part you're right. but here is the fault :
 172.20.0.1/23 = 172.20.0.0 -> 172.20.1.255
 172.20.0.1/22 = 172.20.0.0 -> 172.20.3.255
 172.20.4.1/21 = 172.20.0.0 -> 172.20.7.255
 172.20.6.1/21 = 172.20.0.0 -> 172.20.7.255

so all your networks are overlapping, which isn't good. each address must be unique. so a correct design would be like this : 
 172.20.0.0/21  = 172.20.0.0  -> 172.20.7.255
 172.20.8.0/21  = 172.20.8.0  -> 172.20.15.255
 172.20.16.0/22 = 172.20.16.0  -> 172.20.19.255
 172.20.20.0/23 = 172.20.20.0 -> 172.20.21.255

you can start from the largest networks to the smallest, with the starting address being the last+1 from the previous network. 

a: your serial connections subnet is off: you are specifying a 192.168.1.0/30 for 4 point to point connections @ 2 addresses each = 8 needed ips.  a /30 cidr will only yield 2 available host addresses (enough for only one connection).  you should have a single /30 subnet for each point to point: 
192.168.1.0/30  = 192.168.1.0  -> 192.168.1.3  (use .1 & .2)
192.168.1.4/30  = 192.168.1.4  -> 192.168.1.7  (use .5 & .6)
192.168.1.8/30  = 192.168.1.8  -> 192.168.1.11 (use .9 & .10)
192.168.1.12/30 = 192.168.1.12 -> 192.168.1.15 (use .13 & .14)


a: switches:
new york --> lga 172.20.0.0/21
los angeles --> 172.20.8.0/21
dallas --> dfw 170.20.20.0/23
chicago --> ord 172.20.16.0/22

routers:
192.168.1.13 ord s0/1
192.168.1.14 lax s0/0

192.168.1.1 dfw s0/0
192.168.1.2 lax s0/1

192.168.1.5 dfw 0/1
192.168.1.6 lga s0/0

192.168.1.9 lga s0/1
192.168.1.10 ord s0/0



user
The text includes 21 "="s in total.
assistant