Introduction to Classless Routing
From Mycomputer Notes
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A routing protocol that allows VLSM gives the network administrator freedom to use different subnet masks for networks within a single autonomous system. Figure shows an example of how a network administrator can use a 30-bit mask for network connections, a 24-bit mask for user networks, and even a 22-bit mask for networks with up to 1000 users. | A routing protocol that allows VLSM gives the network administrator freedom to use different subnet masks for networks within a single autonomous system. Figure shows an example of how a network administrator can use a 30-bit mask for network connections, a 24-bit mask for user networks, and even a 22-bit mask for networks with up to 1000 users. | ||
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Revision as of 22:55, 14 September 2006
Network administrators must anticipate and manage the physical growth of networks. This may require them to buy or lease another floor of a building for new network equipment such as racks, patch panels, switches, and routers. Network designers must choose address schemes that allow for growth.
IPv4 offered an address strategy that was scalable for a time before it resulted in an inefficient allocation of addresses. IPv4 may soon be replaced with IP version (6) IPv6 as the dominant protocol of the Internet. IPv6 has virtually unlimited address space and implementation has begun in some networks.
As the enterprise network grows an Network Administrator need to work with its IP address more efficiently; in this section VLSM will be introduced.
In order to used VSLM an administrator must configured a router with a routing protocol that supports it. Cisco routers support VLSM with:
- OSPF
- Integrate IS-IS
- EIGRP
- Static Routing
VLSM allows an organization to use more than one subnet mask within the same network address space. VLSM implementation maximizes address efficiency, and is often referred to as subnetting a subnet.
Classful routing protocols require that a single network use the same subnet mask. As an example, a network with an address of 192.168.187.0 can use just one subnet mask, such as 255.255.255.0.
A routing protocol that allows VLSM gives the network administrator freedom to use different subnet masks for networks within a single autonomous system. Figure shows an example of how a network administrator can use a 30-bit mask for network connections, a 24-bit mask for user networks, and even a 22-bit mask for networks with up to 1000 users.
[IP Mask]
