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Why wildmask when we have the Subnet Mask

Question asked by lovejeet in #Coffee Room on Aug 19, 2013
lovejeet
lovejeet · Aug 19, 2013
Member of CrazyEngineers
While configuring the routers, i came across some of the commands where we use wildcard masks instead of subnet mask, so what is the use of using wildcard mask when subnet masks can solve the same????? Posted in: #Coffee Room
Nayan Goenka
Nayan Goenka · Aug 19, 2013
Member of CrazyEngineers
Good question. Wildcard Mask denotes the standard configuration of any network segment you wish to assign. The Wi-fi and Ethernet routing is different and so is their subnet masking system. Wildcard mask makes it standardized. Plus it allows you to globally allot the settings over all the concerning networks. Irrespective of your V-LANs.
lovejeet
lovejeet · Aug 19, 2013
Member of CrazyEngineers
@Nayan Goenka - Can you please explain the above? I mean how the subnet masking system of wi-fi and ethernet are different, and why can't we use subnet masks as a standard?
Nayan Goenka
Nayan Goenka · Aug 19, 2013
Member of CrazyEngineers
lovejeet
@Nayan Goenka - Can you please explain the above? I mean how the subnet masking system of wi-fi and ethernet are different, and why can't we use subnet masks as a standard?

I think it is better I give you a detailed link to study this.
https://packetlife.net/blog/2008/sep/11/mask-comparison-subnet-versus-wildcard/

For the difference in Wi-Fi and Ethernet, in automatic mode, the access point may vary from the point of connection. In that case, the device may capture some mask which would not be intended and may vary from connection pattern.

Actually WCM and SNM are mirrors in some sense. WCM offers more flexibility than SNM
durga ch
durga ch · Aug 19, 2013
Member of CrazyEngineers
ok, this dates back in history and is related to electronics to some extent. Firstly, subnet masks are used to derive the SUBNET to which a host belong. for example- consider the IP address 192.168.1.1/24 => the subnet mask here is 255.255.255.0 and the network to which the host belong is 192.168.1.0 .
How did we derive the network IP? by 'OR' ing the subnet mask and the host IP.

Now , widlcard masks are used to deduce /indicate the HOSTS for a given network. When you configure OSPF , you write -network 10.0.0.0 0.0.0.255 area 0 , which implies - " consider all interfaces with IP 10.0.0.0 - 10.0.0.255' . Here you perform a logical 'XOR'.

wildcard masks existed all from the start of internetworks to indicate the HOSTs IPs what can be configured, subnetting (CIDR )was introduced only later somewhere in 90s when we had to break the network into subnetworks.

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