Differences between version 4 and previous revision of SubnetAddressing.
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| Newer page: | version 4 | Last edited on Tuesday, December 3, 2002 10:17:54 am | by CraigMckenna | Revert |
| Older page: | version 3 | Last edited on Tuesday, December 3, 2002 10:14:10 am | by CraigMckenna | Revert |
@@ -17,11 +17,11 @@
Address MSB
Class Pattern
-Class A
-Class B 10
-Class C 110
+Class A %%%
+Class B 10%%%
+Class C 110%%%
!Class A Address Example
@@ -119,46 +119,48 @@
!The subnet-host number tradeoff
Here's a table that let's you see at a glance the trade off between the number of subnets and hosts with different subnet masks for both Class B and Class C addresses. We've already subtracted two from the results in the last two columns to take the reserved network and host numbers into account:
-Class B Subnetting:
+!
Class B Subnetting:
# Mask Bits Subnet Mask # Subnets # Hosts
-2 255.255.192.0 2 16382
-3 255.255.224.0 6 8190
-4 255.255.240.0 14 4094
-5 255.255.248.0 30 2046
-6 255.255.252.0 62 1022
-7 255.255.254.0 126 510
-8 255.255.255.0 254 254
-9 255.255.255.128 510 126
-10 255.255.255.192 1022 62
-11 255.255.255.224 2046 30
-12 255.255.255.240 4094 14
-13 255.255.255.248 8190 6
-14 255.255.255.252 16382 2
+2 255.255.192.0 2 16382%%%
+3 255.255.224.0 6 8190%%%
+4 255.255.240.0 14 4094%%%
+5 255.255.248.0 30 2046%%%
+6 255.255.252.0 62 1022%%%
+7 255.255.254.0 126 510%%%
+8 255.255.255.0 254 254%%%
+9 255.255.255.128 510 126%%%
+10 255.255.255.192 1022 62%%%
+11 255.255.255.224 2046 30%%%
+12 255.255.255.240 4094 14%%%
+13 255.255.255.248 8190 6%%%
+14 255.255.255.252 16382 2%%%
-Class C Subnetting:
+!
Class C Subnetting:
# Mask Bits Subnet Mask # Subnets # Hosts
-2 255.255.255.192 2 62
-3 255.255.255.224 6 30
-4 255.255.255.240 14 14
-5 255.255.255.248 30 6
-6 255.255.255.252 62 2
+2 255.255.255.192 2 62%%%
+3 255.255.255.224 6 30%%%
+4 255.255.255.240 14 14%%%
+5 255.255.255.248 30 6%%%
+6 255.255.255.252 62 2%%%
-The Subnet Advantage
+!
The Subnet Advantage
Subnetting hides the internal network organization to external routers and thus simplies routing. For instance, a subnetted Class B address would require fewer routes than the equivalent number of Class C addresses. Shorter routing tables mean faster network transfers.
Subnetting allows address administration to be decentralized. Besides technical advantages, this approach may also provide political benefits for the organization. For instance, an administrator could assi gn a subnet to a department, which would then be responsible for their own network management.
Subnetting can help overcome distance limitations of physical networks by dividing up a physical network into individually addressed networks so they can be connected logically with routers.
-Example: Subnetting a Class C Network
+
+
+!
Example: Subnetting a Class C Network
One of the first things a network administrator needs to do is define the requirements for the network. The logical place to start is to consider how many hosts are on the network.
Using the maximum number of hosts on one Ethernet segment is generally not good practice because it could create performance problems due to network congestion. If you only have one Class C address assigned to your network then what can you do? Refer to our table above that depicts the Class C address subnetting network number-host trade off.
