VLSM Fundamentals - Revision history

Jonk0002 at 21:24, 11 May 2011

2011-05-11T21:24:35Z

@@ Line 48: / Line 48: @@
-::             CIDR  (Default subnet mask plus the number of host bits borrowed)
+{|
-::
-::                                                                                      Class A              Class B          Class C
-::		Binary (N/H)	       Decimal	Block size	(2nd octet)	   (3rd octet)     (4th octet)
-::		-----------------------------------------------------------------------------
+! CIDR/Default Subnet Mask Table
-::		00000000     =    0               256                  /8                      /16                 /24
+|-
-::		10000000     =    128          128                  /9                      /17                 /25
-::		11000000     =    192          64                    /10                    /18                 /26
-::		11100000     =    224          32                    /11                    /19                 /27
-::		11110000     =    240          16                    /12                    /20                 /28
-::		11111000     =    248          8                      /13                    /21                 /29
+! Class A
-::		11111100     =    252          4                      /14                    /22                 /30
+! Class B
-::		11111110     =    254          2                      /15                    /23
+! Class C
-::		11111111     =    255          1
-::
+|-
 === '''Subnetting in your head (5 questions)''' ===

Jonk0002 at 13:04, 9 May 2011

2011-05-09T13:04:22Z

Jonk0002 at 12:55, 9 May 2011

2011-05-09T12:55:44Z

← Older revision		Revision as of 12:55, 9 May 2011
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	:: 4. 198.168.10.48 /28 255.255.255.240 Wan1-2 IPs 12 addresses not used		:: 4. 198.168.10.48 /28 255.255.255.240 Wan1-2 IPs 12 addresses not used
	:: 5. 198.168.10.64 /28 255.255.255.240 LAN4-10 Hosts 6 addresses not used		:: 5. 198.168.10.64 /28 255.255.255.240 LAN4-10 Hosts 6 addresses not used
	::
	:: *Network 1 does not have enough IP address available to assign to the number of hosts existing. The other networks all have excess IP address.		:: *Network 1 does not have enough IP address available to assign to the number of hosts existing. The other networks all have excess IP address.

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	:: 4. 198.168.10.64 /29 255.255.255.248 6 Hosts All addresses used		:: 4. 198.168.10.64 /29 255.255.255.248 6 Hosts All addresses used
	:: 5. 198.168.10.72 /30 255.255.255.252 2 Hosts All addresses used		:: 5. 198.168.10.72 /30 255.255.255.252 2 Hosts All addresses used
	::
	:: *Network 1 now has enough IP address for the number of host. Network 2 & 3 have more efficiency. Networks 4 & 5 are full. The networks have the right amount of address space to assign, but there is still addresses available for future expansion of additional LANs and WANs.		:: *Network 1 now has enough IP address for the number of host. Network 2 & 3 have more efficiency. Networks 4 & 5 are full. The networks have the right amount of address space to assign, but there is still addresses available for future expansion of additional LANs and WANs.

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	== Steps to ~~follow when creating your~~ IP plan using VLSM ==		== Steps to create IP plan using VLSM ==

	:1. First know how to determine your Block sizes and how to create Subnet Masks from the charts.		:1. First know how to determine your Block sizes and how to create Subnet Masks from the charts.

Jonk0002 at 12:52, 9 May 2011

2011-05-09T12:52:37Z

← Older revision		Revision as of 12:52, 9 May 2011
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	:: CIDR (Default subnet mask plus the number of host bits borrowed)		:: CIDR (Default subnet mask plus the number of host bits borrowed)
	::		::
	:: Networks Class A Class B Class C		:: Networks Class A Class B Class C
	:: Binary (N/H) Decimal Block size ~~Interesting Octet~~ (2nd octet) (3rd octet) (4th octet)		:: Binary (N/H) Decimal Block size (2nd octet) (3rd octet) (4th octet)
	:: -----------------------------------------------------------------------------		:: -----------------------------------------------------------------------------
	:: 00000000 = 0 ~~256~~ /8 /16 /24		:: 00000000 = 0 256 /8 /16 /24
	:: 10000000 = 128 ~~128~~ /9 /17 /25		:: 10000000 = 128 128 /9 /17 /25
	:: 11000000 = 192 64 /10 /18 /26		:: 11000000 = 192 64 /10 /18 /26
	:: 11100000 = 224 32 /11 /19 /27		:: 11100000 = 224 32 /11 /19 /27
	:: 11110000 = 240 16 /12 /20 /28		:: 11110000 = 240 16 /12 /20 /28
	:: 11111000 = 248 8 /13 /21 /29		:: 11111000 = 248 8 /13 /21 /29
	:: 11111100 = 252 4 /14 /22 /30		:: 11111100 = 252 4 /14 /22 /30
	:: 11111110 = 254 2 /15 /23		:: 11111110 = 254 2 /15 /23
	:: 11111111 = 255 1		:: 11111111 = 255 1
	::		::
	=== '''Subnetting in your head (5 questions)''' ===		=== '''Subnetting in your head (5 questions)''' ===
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	:: 4. What is the broadcast address for each subnet? It is alway all 1's, which is decimal 255. This is 1 less than each subnet address.		:: 4. What is the broadcast address for each subnet? It is alway all 1's, which is decimal 255. This is 1 less than each subnet address.
	:: 5. What are the valid hosts in each subnet? '''2^H - 2''', Always the addresses between the subnet address and the broadcast address.		:: 5. What are the valid hosts in each subnet? '''2^H - 2''', Always the addresses between the subnet address and the broadcast address.
	::
	::
	:: Ex.		:: Ex.
	:: IP address: 192.168.10.0 /25		:: IP address: 192.168.10.0 /25
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	=== '''IP Subnet-zero''' ===		=== '''IP Subnet-zero''' ===
	::This command allows you to use the first and the last subnet in your network design. Cisco has turned this command on by default starting with Cisco IOS version 12.x and later. If it is turned off for some reason, you can re-enable it manually in your configuration otherwise you have to use the formula of 2^N - 2 to identify the number of networks.		::This command allows you to use the first and the last subnet in your network design. Cisco has turned this command on by default starting with Cisco IOS version 12.x and later. If it is turned off for some reason, you can re-enable it manually in your configuration otherwise you have to use the formula of 2^N - 2 to identify the number of networks.


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	:: Networks 2^4 = 16		:: Networks 2^4 = 16
	:: Hosts/subnet 2^4 - 2 = 14		:: Hosts/subnet 2^4 - 2 = 14
	::
	:: Ex: Classful network		:: Ex: Classful network
	::		::
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	::		::
	:: *Network 1 does not have enough IP address available to assign to the number of hosts existing. The other networks all have excess IP address.		:: *Network 1 does not have enough IP address available to assign to the number of hosts existing. The other networks all have excess IP address.
	::
	::
	:: Ex: Classless network design		:: Ex: Classless network design
	::		::
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	= '''Implementing VLSM networks''' =		= '''Implementing VLSM networks''' =

	:The fundamental goal of VLSM subnetting is to preserve IP addresses on a local network by subdividing the network Host bits into smaller and more		:The fundamental goal of VLSM subnetting is to preserve IP addresses on a local network by subdividing the network Host bits into smaller and more efficient subnetworks.
	efficient subnetworks.

	:VLSM is the most efficient use of the number of Hosts in an address class.		:VLSM is the most efficient use of the number of Hosts in an address class.

	:There are multiple solutions possible when subnetting you network and they may all be correct. It would be your decision as to how you want to		:There are multiple solutions possible when subnetting you network and they may all be correct. It would be your decision as to how you want to subdivide your address space.
	subdivide your address space.

	:Your network addresses should make sense when planning for current networks and for future growth. Be careful that you do not crossover into the		:Your network addresses should make sense when planning for current networks and for future growth. Be careful that you do not crossover into the
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	:: VLSM subnet worksheet		:: VLSM subnet worksheet
	::
	:: Ex.		:: Ex.
	:: 192.168.10.0		:: 192.168.10.0
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	:: G 2 4 /30 252		:: G 2 4 /30 252
	:: H 2 4 /30 252		:: H 2 4 /30 252
	::
	::

	:: VLSM worksheet		:: VLSM worksheet
	:: -----------------------		:: -------------------------------------------
	:: 0 -		:: 0 -
	:: 4 -		:: 4 -

Jonk0002 at 12:42, 9 May 2011

2011-05-09T12:42:58Z

Show changes

Jonk0002 at 04:22, 9 May 2011

2011-05-09T04:22:59Z

← Older revision		Revision as of 04:22, 9 May 2011
Line 45:		Line 45:

	:Add the number of binary bit borrowed to the default subnet mask for the class your address is in to create your CIDR notation.		:Add the number of binary bit borrowed to the default subnet mask for the class your address is in to create your CIDR notation.
	:Place your Decimal representation in the interesting octet of the subnet mask to create the mask for the subnet.~~''''''''''[]]]]]]]]]]]]]]]]]]~~		:Place your Decimal representation in the interesting octet of the subnet mask to create the mask for the subnet.

Jonk0002 at 04:15, 9 May 2011

2011-05-09T04:15:41Z

← Older revision		Revision as of 04:15, 9 May 2011
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	= '''Subnetting Basics''' =		= '''Subnetting Basics''' =

	::When designing your network using '''VLSM''' you must already have the basics of subnetting classful networks. No matter what class a networks is in it is using the same subnet mask. A subnet mask is a 32-bit value which will allow the receiver of IP packets to determine the network portions of the IP address from the host portion. It is important that you can determine the subnet masks quickly and accurately. The subnet mask is composed of 1's and 0's. The 1's will signify the network or the subnet address.		:When designing your network using '''VLSM''' you must already have the basics of subnetting classful networks. No matter what class a networks is in it is using the same subnet mask. A subnet mask is a 32-bit value which will allow the receiver of IP packets to determine the network portions of the IP address from the host portion. It is important that you can determine the subnet masks quickly and accurately. The subnet mask is composed of 1's and 0's. The 1's will signify the network or the subnet address.

	::There are many different ways to subnet a network, but regardless of the address class there are some similarities.		:There are many different ways to subnet a network, but regardless of the address class there are some similarities.
	::Remember that subnet bits start from the left to the right and do not skip over any bits. Observe and identify the most interesting octet of the subnet mask. In that octet you will be able to determine the subnet mask and the CICR values that represent that subnet mask.		:Remember that subnet bits start from the left to the right and do not skip over any bits. Observe and identify the most interesting octet of the subnet mask. In that octet you will be able to determine the subnet mask and the CICR values that represent that subnet mask.

	::Using this chart you may be able to determine your subnet mask and the CIDR notation for each class.		:Using this chart you may be able to determine your subnet mask and the CIDR notation for each class.

	:::Class A addresses have '''8''' bits on for network and 24 bits for hosts. Default subnet mask is 255.0.0.0 with CIDR of '''/8'''		::Class A addresses have '''8''' bits on for network and 24 bits for hosts. Default subnet mask is 255.0.0.0 with CIDR of '''/8'''
	:::Class B addresses have '''16''' bits on for network and 16 bits for hosts. Default subnet mask is 255.255.0.0 with CIDR of '''/16'''		::Class B addresses have '''16''' bits on for network and 16 bits for hosts. Default subnet mask is 255.255.0.0 with CIDR of '''/16'''
	:::Class C addresses have '''24''' bits on for network and 8 bits for hosts. Default subnet mask is 255.255.255.0 with CIDR of '''/24'''		::Class C addresses have '''24''' bits on for network and 8 bits for hosts. Default subnet mask is 255.255.255.0 with CIDR of '''/24'''

	::Add the number of binary bit borrowed to the default subnet mask for the class your address is in to create your CIDR notation.		:Add the number of binary bit borrowed to the default subnet mask for the class your address is in to create your CIDR notation.
	::Place your Decimal representation in the interesting octet of the subnet mask to create the mask for the subnet.		:Place your Decimal representation in the interesting octet of the subnet mask to create the mask for the subnet.''''''''''[]]]]]]]]]]]]]]]]]]
	;;

	;; CIDR (Default subnet mask plus the number of host bits borrowed)		;; CIDR (Default subnet mask plus the number of host bits borrowed)
	;;		;;

Jonk0002 at 04:12, 9 May 2011

2011-05-09T04:12:28Z

← Older revision		Revision as of 04:12, 9 May 2011
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	::Using this chart you may be able to determine your subnet mask and the CIDR notation for each class.		::Using this chart you may be able to determine your subnet mask and the CIDR notation for each class.

	:::Class A addresses have 8 bits on for network and 24 bits for hosts. Default subnet mask is 255.0.0.0 with CIDR of /8		:::Class A addresses have '''8''' bits on for network and 24 bits for hosts. Default subnet mask is 255.0.0.0 with CIDR of '''/8'''
	:::Class B addresses have 16 bits on for network and 16 bits for hosts. Default subnet mask is 255.255.0.0 with CIDR of /16		:::Class B addresses have '''16''' bits on for network and 16 bits for hosts. Default subnet mask is 255.255.0.0 with CIDR of '''/16'''
	:::Class C addresses have 24 bits on for network and 8 bits for hosts. Default subnet mask is 255.255.255.0 with CIDR of /24		:::Class C addresses have '''24''' bits on for network and 8 bits for hosts. Default subnet mask is 255.255.255.0 with CIDR of '''/24'''

	::Add the number of binary bit borrowed to the default subnet mask for the class your address is in to create your CIDR notation.		::Add the number of binary bit borrowed to the default subnet mask for the class your address is in to create your CIDR notation.

Jonk0002 at 04:10, 9 May 2011

2011-05-09T04:10:33Z

← Older revision		Revision as of 04:10, 9 May 2011
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	== '''Definitions''' ==		== '''Definitions''' ==
	::'''VLSM''': Variable-length Subnet Masks, is simply a method used to divide a network into subnets and conserve the use of IP address.		:'''VLSM''': Variable-length Subnet Masks, is simply a method used to divide a network into subnets and conserve the use of IP address.

	::'''CIDR''': Classless Inter-Domain Routing, uses Variable-length Subnet Masks to define routes.		:'''CIDR''': Classless Inter-Domain Routing, uses Variable-length Subnet Masks to define routes.

	::'''N''': Network bits taken from the Host portion of the IP address and are reserved to define the subnets. These Bits are turned on or equal to 1 from the left to the right.		:'''N''': Network bits taken from the Host portion of the IP address and are reserved to define the subnets. These Bits are turned on or equal to 1 from the left to the right.

	::'''H''': Host bits are the remaining portion of the IP address which is not defined to the network. The more Network bits you use the less available Hosts there are for the subnet.		:'''H''': Host bits are the remaining portion of the IP address which is not defined to the network. The more Network bits you use the less available Hosts there are for the subnet.

	::'''Network of subnet address''': The beginning address of each subnet. Can be determined by using the ANDing process.		:'''Network of subnet address''': The beginning address of each subnet. Can be determined by using the ANDing process.

	::'''Broadcast address''': The highest IP address in a subnet before entering the next network.		:'''Broadcast address''': The highest IP address in a subnet before entering the next network.

	::'''Network increment''': Size of the increase between the starting network boundary .		:'''Network increment''': Size of the increase between the starting network boundary .

	::'''Block size''': Another term for Network increment.		:'''Block size''': Another term for Network increment.

	::'''Interesting Octet''': IP address octet which is being subnetted. This will be the octet of the subnet mask that is not 0's or 255.		:'''Interesting Octet''': IP address octet which is being subnetted. This will be the octet of the subnet mask that is not 0's or 255.

Jonk0002 at 04:09, 9 May 2011

2011-05-09T04:09:52Z

← Older revision		Revision as of 04:09, 9 May 2011
Line 46:		Line 46:
	::Add the number of binary bit borrowed to the default subnet mask for the class your address is in to create your CIDR notation.		::Add the number of binary bit borrowed to the default subnet mask for the class your address is in to create your CIDR notation.
	::Place your Decimal representation in the interesting octet of the subnet mask to create the mask for the subnet.		::Place your Decimal representation in the interesting octet of the subnet mask to create the mask for the subnet.
			;;
	;; CIDR (Default subnet mask plus the number of host bits borrowed)		;; CIDR (Default subnet mask plus the number of host bits borrowed)
	;; Networks Class A Class B Class C		;;
	;; Binary (N/H) Decimal Block size Interesting Octet (2nd octet) (3rd octet) (4th octet)		;; Networks Class A Class B Class C
			;; Binary (N/H) Decimal Block size Interesting Octet (2nd octet) (3rd octet) (4th octet)
	;; -----------------------------------------------------------------------------		;; -----------------------------------------------------------------------------
	;; 00000000 = 0 256 /8 /16 /24		;; 00000000 = 0 256 /8 /16 /24
	;; 10000000 = 128 128 /9 /17 /25		;; 10000000 = 128 128 /9 /17 /25
	;; 11000000 = 192 64 /10 /18 /26		;; 11000000 = 192 64 /10 /18 /26
	;; 11100000 = 224 32 /11 /19 /27		;; 11100000 = 224 32 /11 /19 /27
	;; 11110000 = 240 16 /12 /20 /28		;; 11110000 = 240 16 /12 /20 /28
	;; 11111000 = 248 8 /13 /21 /29		;; 11111000 = 248 8 /13 /21 /29
	;; 11111100 = 252 4 /14 /22 /30		;; 11111100 = 252 4 /14 /22 /30
	;; 11111110 = 254 2 /15 /23		;; 11111110 = 254 2 /15 /23
	;; 11111111 = 255 1		;; 11111111 = 255 1
	;;		;;
	=== '''Subnetting in your head''' ===		=== '''Subnetting in your head''' ===
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	;; The following charts show the difference in how wasteful Classful networks are verses the more efficient Classless VLSM network.		;; The following charts show the difference in how wasteful Classful networks are verses the more efficient Classless VLSM network.
			;;
	;; Network 198.168.10.0		;; Network 198.168.10.0
	;; Mask 255.255.255.240 (/28)		;; Mask 255.255.255.240 (/28)
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	= Implementing VLSM networks =		= '''Implementing VLSM networks''' =

	;The fundamental goal of VLSM subnetting is to preserve IP addresses on a local network by subdividing the network Host bits into smaller and more		;The fundamental goal of VLSM subnetting is to preserve IP addresses on a local network by subdividing the network Host bits into smaller and more
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	;; VLSM subnet worksheet		;; VLSM subnet worksheet
			;;
	;; Ex.		;; Ex.
	;; 192.168.10.0		;; 192.168.10.0
			;;
	;; Network Host Block Subnet Mask		;; Network Host Block Subnet Mask
	;; ---------- ---------- ---------- ---------- ----------		;; ---------- ---------- ---------- ---------- ----------
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	;; G 2 4 /30 252		;; G 2 4 /30 252
	;; H 2 4 /30 252		;; H 2 4 /30 252
			;;
			;;
	;; VLSM worksheet		;; VLSM worksheet
	;; -----------------------		;; -----------------------

← Older revision		Revision as of 13:04, 9 May 2011
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	:: CIDR (Default subnet mask plus the number of host bits borrowed)		:: CIDR (Default subnet mask plus the number of host bits borrowed)
	::		::
	:: ~~Networks~~ Class A Class B Class C		:: Class A Class B Class C
	:: Binary (N/H) Decimal Block size (2nd octet) (3rd octet) (4th octet)		:: Binary (N/H) Decimal Block size (2nd octet) (3rd octet) (4th octet)
	:: -----------------------------------------------------------------------------		:: -----------------------------------------------------------------------------
	:: 00000000 = 0 256 /8 /16 /24		:: 00000000 = 0 256 /8 /16 /24
	:: 10000000 = 128 128 /9 /17 /25		:: 10000000 = 128 128 /9 /17 /25
	:: 11000000 = 192 64 /10 /18 /26		:: 11000000 = 192 64 /10 /18 /26
	:: 11100000 = 224 32 /11 /19 /27		:: 11100000 = 224 32 /11 /19 /27
	:: 11110000 = 240 16 /12 /20 /28		:: 11110000 = 240 16 /12 /20 /28
	:: 11111000 = 248 8 /13 /21 /29		:: 11111000 = 248 8 /13 /21 /29
	:: 11111100 = 252 4 /14 /22 /30		:: 11111100 = 252 4 /14 /22 /30
	:: 11111110 = 254 2 /15 /23		:: 11111110 = 254 2 /15 /23
	:: 11111111 = 255 1		:: 11111111 = 255 1
	::		::

	=== '''Subnetting in your head (5 questions)''' ===		=== '''Subnetting in your head (5 questions)''' ===
	:: 1. How many subnets? '''2^N'''		:: 1. How many subnets? '''2^N'''