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VLSM (Variable Length Subnet Masks) allows you to use different masks for each subnet
CIDR (classless inter domain routing) use for allocate ip address and ip routing (network portion)
VLSM= Variable length subnet mask eg 172.16.32.0/24
CIDR :- Classless inter domain routing , it is supported by dynamic routing such as OSPF, EIGRP , BGP
VLSM (Variable Length Subnet Masks) is an extension of
CIDR that makes it possible to subnet a globally assignedblock of address space using different masks, so as to beable to have different size subnets within the same block.In the old classful days, it was necessary to use one andonly one subnet mask per address block, so all subnets hadto be the same size.
CIDR further two types VLSM and FLSM.
FLSM is fixed length subnet mask
/8 for class A 255.0.0.0
/16 for class B 255.255.0.0
/24 for class C 255.255.255.0
This was old technology and there was a lot of wastage of ip's.
so someone(i don't know who) come with conclusion that we can use
CIDR/VLSM-- Classless inter domain routing/variable length subnet mask
so now we can further use
/9 = X.128.0.0
/18= X.X.192.0
/27= X.X.X.224
/30= X.X.X.252 in case of /30 there will be one network id one broadcast ip and two valid host ip
benefit- no wastage of ip even if we have to assign ip to two hosts
VLSM (Variable Length Subnet Masks) means Subnetting subnets, that is a process of dividing an IP network into the subnets of different sizes without wasting IP addresses.
CIDR (Classless Inter-Domain Routing) is a method for allocating IP addresses and IP routing. Sometimes called supernetting
Classless Inter-Domain Routing: is a method for allocating IP addresses and IP routing. Sometimes called super netting.
Variable Length Subnet Masks: means Subnetting subnets, that is a process of dividing an IP network into the subnets of different sizes without wasting IP addresses.
