Tuesday, July 8, 2014
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Please disregard anything on this blog as it relates to IP Networking Class NT2640.
Any further homework information will be delivered in class and via email. Assignments will come via email and dead trees.
Subnetting Lab 5 EMS Simplified
Read the lab details listed below, and then
answer the questions listed in the lab exercise.
“EMS” Simplified
Method for CIDR Class B
In subnetting CIDR “Classless Inter-Domain Routing” for a Class B
address the process is again very much the same in creating the cheat sheet
chart that we did in a Class C address. The difference now is that now we are
using the third and fourth octets that we used in the Class C address. This is
because the first two octets are the network values, and the last two Octets
are the host values as shown here:
Now we will take the same standard Class B guide, but we want a
value in the 4th octet. For example, we again want 30 host IP’s but
we want them on 2000 networks. Notice below that we get this from the guide at
the 32-bit value in the 4th octet as identified below.
Below we see the Class B Subnetting Guide created the same way we
did the Class C Subnetting Guide.
Class-B Subnetting Guide
Remember that using this Cheat-Sheet Guide gives us the usable
numbers available for the creation of subnetworks and hosts. The numbers on
line 2 are again the numbers of usable hosts. The numbers on line 3 are again
the number of usable Sub-networks. That is because we took away both the
Network IP and Broadcast IP from each out of line 1.
We again subnet a Class B with this guide by giving up bits from
left to right starting with the 128 bit on the far left in the 3rd octet
and moving right to get the subnet range we want. If you want 30 host computers
on each of the 2000 subnetworks You would give up the 128 bit through the 1 bit
in the 3rd octet as well as the 128, the 64, and the 32 bit values
of line 1 of the 4th octet. That means you would borrow all 8 bits
from the 3rd octet and three more bits from the 4th octet.
This now moves down into a Class C range, hence the term CIDR, which stands for
Classless Inter-Domain Routing. You can identify this by drawing a line down
from the 4 past the 1022 to the 62 as indicated in the example above.
These same processes for a CIDR Class-B can be seen here in Table
3.
Subnet 1
|
3rd Octet
0.
|
172.16.0
|
4th
Octet Values
0---------31
|
Assignable 4th
Octet Values
1-------30
|
Subnet 2
|
0.
|
172.16.0
|
32--------63
|
33------62
|
Subnet 3
|
0.
|
172.16.0
|
64--------95
|
65------94
|
Subnet 4
|
0.
|
172.16.0
|
96-------127
|
97-----126
|
Subnet 5
|
0.
|
172.16.0
|
128------159
|
129----158
|
Subnet 6
|
0.
|
172.16.0
|
160------191
|
161----190
|
Subnet 7
|
0.
|
172.16.0
|
192------223
|
193----222
|
Subnet8
|
0.
|
172.16.0
|
224------255
|
225----254
|
Subnet 9
|
1.
|
172.16.1
|
0---------31
|
1-------30
|
Subnet 10
|
1.
|
172.16.1
|
32--------63
|
33------62
|
Subnet 11
|
1.
|
172.16.1
|
64--------95
|
65------94
|
Subnet 12
|
1.
|
172.16.1
|
96-------127
|
97-----126
|
Subnet 13
|
1.
|
172.16.1
|
128------159
|
129----158
|
Subnet 14
|
1.
|
172.16.1
|
160------191
|
161----190
|
Subnet 15
|
1.
|
172.16.1
|
192------223
|
193----222
|
Subnet16
|
1.
|
172.16.1
|
224------255
|
225----254
|
This table would continue down until the 3rd octet has used all
values from 0 to 255.
Subnetting Lab 5
Exercise
Using the Class B Subnetting Guide, answer the following:
Tuesday, July 1, 2014
Subnetting Lab 4
Read the lab details listed below, and then
answer the questions listed in the lab exercise.
“EMS” Simplified
Method Class B
In subnetting a Class B address, the process is the same in
creating the cheat sheet chart that we did in a Class C address. The added
difference is that now we are using the third octet as well as the forth octet that
was used in the Class C address. This is because the first two octet are the
network values and now, the last two Octets are the Host values as shown
here: 172.16. 3 . 5
Network Host
Below we see the Class B Subnetting Guide created the same way we
did in the Class C Subnetting Guide.
Class B Subnetting Guide
Groups: 128 64 32
16 8
4 2
1
1. IP’s: 32768 16384
8192 4096 2048 1024 512 256 128 64
32 16 8
4 2
1
2. Hosts: 32766 16382 8190 4094 2046 1022 510 254 126 62
30 14 6
2 0
3. Subnets: 0 2 6 14 30
62 126 254 510 1022
2046 4094 8190 16382 32766
The steps to create a Class B Subnetting Guide is to continue
line/row 1 by multiplying each value by two from right to left. Line 1 is still
the number of IP addresses in total in each new subnet. Step 2 for line/row 2
we again subtract two out of each value which is the 2 reserved IP addresses,
the network address and the network broadcast which is again the first and last
value in the subnet range. The 3rd step is to again take the (0)
zero from the right and place it under the last value on the left. Continue
that process until line/row 3 is the reverse of line/row 2 as shown in the
above Class B Subnetting Guide. The final step is to place the value of each bit
place in the 3rd octet by starting with 1 above the 256 in Line 1
and continue in multiples of two until each place has a value from 1 to 128.
These are now the groups of ranges that are in each subnet for a Class B
subnetted address.
Remember that using this Cheat-Sheet Guide gives you the usable
numbers available for the creation of subnetworks and hosts. The numbers on
line 2 are the numbers of usable Hosts. The numbers on line 3 are again the
number of usable subnetworks. That is because we removed both the network IP
and broadcast IP from each out of line 1.
We subnet a Class B with this guide by again giving up bits from
left to right starting with the 128 bit on the far left in the 3rd
Octet and moving right to get the subnet range we want. If we want 1000 host
computers on each of the 60 subnetworks, we would give up the 128, the 64, the
32, the 16, the 8 and the 4 bit values of line 1. That means we would borrow
those 6 bits. We would identify this by drawing a line down from the 4 past the
1022 to the 62 as indicated in the example below.
We started with the default mask of 255.255.0.0. To get the new subnet
mask we simply add the values of each borrowed bit from left to right on line
1. If we add 128, 64, 32, 16, 8, and 4. We get 252. The new subnet mask is
255.255.252.0
To get the subnet mask, simply add the values of each bit we used
to create the subnet.
Groups: 128
64 32 16
8 4 | 2
1
1. IP’s :
32768 16384 8192 4096 2048 1024 | 512 256 128 64 32 16 8 4 2 1
2. Hosts:
32766 16382 8190 4094 2046 1022 | 510 254 126 62 30 14 6 2 0
3. Subnets: 0 2 6 14 30 62
|
126 254 510
1022 2046 4094
8190 16382 32766
If we wanted to create a subnet with 30 hosts on each of 2046
subnetworks as indicated above, we would borrow all the bits of the 3rd
octet and the first three bits of the 4th octet, (always from the
left) or 11 bits.
We would get the subnet mask by adding the values of the 8 bits
in the 3rd octet (or 255) and those we used in the 4th
Octet (or 128 + 64 + 32 = 224) for a subnet mask of 255.255.255.224
Notice the number 4 in the groups column, this gives us the
groupings value of four ranges of 0 to 255 in the 4th octet that
will be used for each of our new Class B subnets. Each subnet is in groups of four,
as indicated by Table 2 below. The first and last subnets are unavailable for
use due to the use of the first subnet 0 as the network value and the last subnet
255 as the broadcast value.
Table 2
|
Subnet
|
3rd Octet
|
Network Number
|
4th Octet Host IP Range
|
Assignable IP Range
|
|
Subnet 1
|
0.
1.
2.
3.
|
172.16.0.
172.16.1.
172.16.2.
172.16.3.
|
0-----------255
0-----------255
0-----------255
0-----------255
|
1----255 0 is the
Network Value
0----255
0----255
0----254 255 is the
Broadcast Value
|
|
Subnet 2
|
4.
5.
6.
7.
|
172.16.4.
172.16.5.
172.16.6.
172.16.7.
|
0-----------255
0-----------255
0-----------255
0-----------255
|
1----255 0 is the
Network Value
0----255
0----255
0----254 255is the
Broadcast Value
|
|
Subnet 3
|
8.
9.
10.
11.
|
172.16.8.
172.16.9.
172.16.10.
172.16.11.
|
0-----------255
0-----------255
0-----------255
0-----------255
|
1----255 0 is the
Network Value
0----255
0----255
0----254 255 is the
Broadcast Value
|
|
Subnet 4
|
12.
13.
14.
15.
|
172.16.12.
172.16.13.
172.16.14.
172.16.15.
|
0-----------255
0-----------255
0-----------255
0-----------255
|
1----255 0 is the
Network Value
0----255
0----255
0----254 255 is the
Broadcast Value
|
This continues until all 256 values from 0 to 255 are used in the
3rd octet vertically. Notice that the 4th octet values
are read horizontally from 0 to 255 where the 3rd Octet is read vertically
from 0 to 255. Table 2 stopped at Subnet 4, but in reality goes on to subnet 64
with four groups in each subnet.
These same processes for Class B is applied depending on what
your needs are in the number of hosts and the number of networks needing subnet
addresses. If we had wanted 2000 hosts on each of the 30 networks, we would
have taken bits down to the 8 and the groups would have been in groups of eight.
Again, this is applied accordingly to your needs.
You may work in small groups for this assignment
Subnet Exercise 3
Using the Ellis
Methodology of Subnetting “EMS”
“EMS” Simplified Method Class C
This is a simplified method of subnetting by remembering a few basic rules. Network Host
2. In
basic subnetting, you don’t use the first IP value as it’s the network address,
and you don’t use the last IP value as it’s the broadcast address.
3. Identify
the value of each bit in an octet beginning with 1 and multiplying it by 2 for
each bit place in an octet as illustrated below in line 1 below.
4. Subtract
your first and last IP values from each bit value in line 1 or take 2 from each
place, as illustrated in line 2 below. If you can’t take 2 from 1, leave it
blank.
5. Reverse
the numbers starting with 0 and place it under 126 of line 2 and continue until
126 is under the zero of line 2, as illustrated in line 3 below.
6. As
you borrow bits from the left you decrease the number of available hosts as you
increase the number of available networks. So, the hosts, line 2, decrease as
the sub-networks, line 3, increase.
7. Now
for any Cisco IOS above 12.0 remember to add two to each value in line 3 as we
gain those networks back in the new version. If use an older IOS, leave the
values as indicated in the chart.
8. Line
or row 1 identifies the quantity of IP addresses for each subnet in total. Line or row 2 identifies how many hosts can
exist in the subnetted range, and line or row 3 identifies how many subnets can
exist in the subnetted range.
9. A
way to remember what each line represents use the first letter from each line
I, H and S and just remember “I Hate Sub-Netting.”
Class C Subnetting Guide
Line 1. “IP’s”
128 64 32 16 8 4 2 1
Line 2. “Hosts” 126 62 30 14 6 2 0
Line
3. “Subnets” 0 2 6 14 30 62 126
Now that you have your Class C “Cheat Sheet,” remember that by using
this guide you can subnet any Class C IP address. Remember that the values on
line 2 are the number of usable hosts and the values on line 3 are the number
of usable sub-networks created when borrowing the bits across the values on
line 1 from left to right. That is because we took away both the network IP and
broadcast IP from each. You can add two back to each value in lines 2 and 3 to
know how many actual hosts and networks are actually created. This is for IOS
11.0 and older.
We begin by giving up bits from left to right starting with the
128 bit and moving right to get the subnet range we want. If we want 30 host
computers on each of the six subnetworks, we would give up the 128, the 64, and
the 32-bit values of line 1; which is the host values of that octet. This means,
we would borrow those three bits. We would identify this by drawing a line down
from the 32 past the 30 to the 6 as indicated in the example below.
To get the subnet mask, simply add the values of each bit you
borrowed from left to right on line 1. If you add 128 and 64 and 32 together you
get 224. Now the new subnet mask is 255.255.255.224
Example
In this example,
we are borrowing the first 3 bits in the 4th octet to give up to
subnetting.
1. 4th Octet bit representation 128 64 32 | 16 8 4 2 1 “IP’s”
2. Subtract First & Last 126 62 30 | 14 6 2 0 “Hosts”
3. Reverse of Line 2 0 2 6 | 14 30 62 126 “Subnets”
Again, if you wanted to create a subnet with 30 hosts on each of six
subnetworks as indicated above, you would borrow the first three bits, always
from the left.
We started with a Class C default mask of 255.255.255.0 To get a
new subnet mask we add the values of the three bits that are used: 128 + 64 +
32 = 224.
That would give us a subnet mask of 255.255.255.224 where the 255
represents the value for the other octets.
Next to get the allocated IP addresses for each subnet, notice
the number 32 in the column you took the bits to. This identifies how many IP
are in each subnet. Each of the subnets are in groups of 32 IP addresses as indicated
by the table below.
This is created by starting with 0, go vertically “down” in
groups of 32 as indicated here:
0
32
64
96
Etc.
to 255 as shown in Table 1 below
This is the first bit value in each of the new subnet ranges. Now
fill in the last value for each subnet range by realizing that it will be one
less than the start of the next range as indicated here:
0------------31
32----------63
64----------95
96---------127
Etc.
to 255 as shown in Table 1 below
Table 1:
Subnet
|
Network Number
|
Host IP Range
|
Usable IP Range
|
Subnet 1
|
192.168.1
|
0-------------31
|
1-30 “First Usable Subnet Range”
|
Subnet 2
|
192.168.1
|
32------------63
|
33-62
|
Subnet 3
|
192.168.1
|
64------------95
|
65-94
|
Subnet 4
|
192.168.1
|
96-----------127
|
97-126
|
Subnet 5
|
192.168.1
|
128---------159
|
129-158
|
Subnet 6
|
192.168.1
|
160---------191
|
161-190
|
Subnet 7
|
192.168.1
|
192---------223
|
193-222
|
Subnet 8
|
192.168.1
|
224---------255
|
225-254 “Last Usable Subnet Range”
|
Remember that we can’t use either the first value in a network
range (it’s reserved as the network number value) or the last value in a
network range (it’s reserved as the network broadcast value).
So, from Table 1 above, we can see that:
·
The IP address, 192.168.1.1 in subnet range 1 is
the first usable address in that subnet range.
·
The IP address, 192.168.1.30 in subnet range 1,
is the last usable address in that subnet range.
·
The IP address, 192.168.1.225 in subnet range 8,
is the first usable address in that subnet range.
·
The IP address, 192.168.1.254 in subnet range 8,
is the last usable address in that subnet range.
The same is true for all of the other ranges between them.
Note that the values in the host IP range are the values
available for the host addresses in the 4th octet. Also, those
values identify both the network value and the broadcast value for each of the
subnets.
The values indicated in the usable IP range are the specific IP
addresses usable only on that subnet.
You may work in small groups for this assignment
Thursday, June 26, 2014
Homework Due 7/1/2014
Please see my email on this subject, including the attached documents.
Homework for the coming week is as follows:
1. Complete the IP Subnetting exercise we began in class. If you missed class, or if you need an additional copy, I sent the document via email.
2. Complete the additional page on subnetting sent via email. Don't worry about the end section where it says to show your work.
3. Complete Labs 3.1 and send me the output from the Grade File. (You should complete the questions for your own use.)
4. Our next class will cover Chapter 12-14, so you should be catching up with the reading there.
Also, if you missed class this past Tuesday, please complete the online quiz in the previous post.
Tuesday, June 24, 2014
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