Difference between Classful Routing and Classless Routing

Classful Routing:
Classful Routing does not import subnet mask. And in this also subnet mask is provided after the route update. In classful routing, subnet mask is same throughout, does not vary for all devices, we can see it in the given picture. In classful routing, VLMS (Variable Length Subnet Mask) is not supported and also CIDR (Classless Inter-Domain Routing).

Classless Routing:
Classless Routing imports subnet mask and in this, triggered updates are used. In classess routing, VLMS (Variable Length Subnet Mask) is supported and also CIDR (Classless Inter-Domain Routing). In classless routing, hello messages are used for checking status. In classless routing, subnet mask is not same throughout, it may vary for all devices, we can see it in the given picture.







Let’s see that the difference between classful routing and classless routing:

S.NO Classful Routing Classless Routing
1. In classful routing, VLMS(Variable Length Subnet Mask) is not supported. While in classess routing, VLMS(Variable Length Subnet Mask) is supported.
2. Classful routing requires more bandwidth. While it requires less bandwidth.
3. In classful routing, hello messages are not used. While in classless routing, hello messages are used.
4. Classful routing does not import subnet mask. Whereas it imports subnet mask.
5. In classful routing, address is divided into three parts which are: Network, Subnet and Host. While in classless routing, address is divided into two parts which are: Subnet and Host.
6. In classful routing, regular or periodic updates are used. Whereas in this, triggered updates are used.
7. In classful routing, CIDR(Classless Inter-Domain Routing) is not supported. While in classess routing, CIDR(Classless Inter-Domain Routing) is supported.



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