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Bài giảng Mạng máy tính nâng cao (Advanced computer networks) - Chapter 07: Variable length subnet masking

Objectives: Define VLSM and briefly describe the reasons for its use; divide a major network into subnets of different sizes using VLSM; define route aggregation and summarization as they relate to VLSM; configure a router using VLSM. | VARIABLE LENGTH SUBNET MASKING MẠNG MÁY TÍNH NÂNG CAO Chapter 07 Objectives Define VLSM and briefly describe the reasons for its use Divide a major network into subnets of different sizes using VLSM Define route aggregation and summarization as they relate to VLSM Configure a router using VLSM Identify the key features of RIP v1 and RIP v2 Identify the important differences between RIP v1 and RIP v2 Configure RIP v2 Verify and troubleshoot RIP v2 operation Issues with IP Addressing Prior to 1981, IP addresses used only the first 8 bits to specify the network portion of the address In 1981, RFC 791 modified the IPv4 32-bit address to allow for three different classes As early as 1992, the IETF identified two specific concerns: IP address exhaustion Routing table growth IP Addressing Solutions Short term to extension to IPv4 Subneting masking: RFCs 950, 1812 Variable-Length Subnet Masks & Classless InterDomain Routing notation (1993, RFC 1519) Network Address Translation (1994, RFC . | VARIABLE LENGTH SUBNET MASKING MẠNG MÁY TÍNH NÂNG CAO Chapter 07 Objectives Define VLSM and briefly describe the reasons for its use Divide a major network into subnets of different sizes using VLSM Define route aggregation and summarization as they relate to VLSM Configure a router using VLSM Identify the key features of RIP v1 and RIP v2 Identify the important differences between RIP v1 and RIP v2 Configure RIP v2 Verify and troubleshoot RIP v2 operation Issues with IP Addressing Prior to 1981, IP addresses used only the first 8 bits to specify the network portion of the address In 1981, RFC 791 modified the IPv4 32-bit address to allow for three different classes As early as 1992, the IETF identified two specific concerns: IP address exhaustion Routing table growth IP Addressing Solutions Short term to extension to IPv4 Subneting masking: RFCs 950, 1812 Variable-Length Subnet Masks & Classless InterDomain Routing notation (1993, RFC 1519) Network Address Translation (1994, RFC 1631) Address allocation for private Internets (1996, RFC 1918) Route summarization: RFC 1518 Ultimate solution: IPv6 128-bit address space Classful IP Addressing Classful Routing Protocol classful routing protocols(i.e. RIPv1) do not send subnet masks in their routing updates The reason is that the Subnet mask is directly related to the network address Classless IP Addressing Classless Inter-domain Routing (CIDR –RFC 1517) Allows for: More efficient use of IPv4 address space Route summarization Requires subnet mask to be included in routing update because address class is meaningless Recall purpose of a subnet mask: To determine the network and host portion of an IP address CIDR and Route Summarization CIDR & Route Summarization Variable Length Subnet Masking (VLSM): Allows a subnet to be further sub-netted according to individual needs CIDR allows for routes to be summarized as a single route Classless Routing Protocol Characteristics of classless routing protocols: Routing updates .