【正文】 000000 11111111 11111111 00000000 00000000 11111111 11111111 11111111 00000000 . . . . IP Address Sub Mask Network ID Host ID 來(lái)自 Possible Sub Masks for Class A, B amp。 a message sent to this address is broadcast to each machine on the sub. ? – send to “all nodes” on work ? Limited Broadcast ? Network ID and/or Host ID Cannot Be All Bits Set to 0 ? used by Cisco routers to designate the default route ? 0 means “this work or segment”, or “this node” ? Host ID Must Be Unique to the Network 來(lái)自 Assigning Network Addresses Router 1 2 3 Router 來(lái)自 Assigning Host Addresses Router Router 1 2 3 來(lái)自 Subting What is a Sub? Why Subting? Implementing Subting Sub Masks Default Sub Masks Possible Sub Masks for Class A, B amp。 C Class C Class B Class A 來(lái)自 Defining a Sub Mask Convert the Number of Segments to Binary Count the Number of Required Bits Convert the Required Number of Bits to Decimal (High Order) 1 2 3 Example of Class B Address Number of Subs Binary Value Convert to Decimal 6 0 0 0 0 0 1 1 0 = 6 (3 Bits) 4+2 255 . 255 . 224 . 0 11111111 11111111 11100000 00000000 Sub Mask 來(lái)自 Defining Sub IDs 255 255 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 00000000 = 0 00100000 = 32 01000000 = 64 01100000 = 96 10000000 = 128 10100000 = 160 11000000 = 192 11100000 = 224 1 2 3 224 Sub Mask 來(lái)自 Defining Host IDs Sub IDs Host ID Range Invalid – – – – – – Invalid 00000000 = 0 00100000 = 32 01000000 = 64 01100000 = 96 10000000 = 128 10100000 = 160 11000000 = 192 11100000 = 224 ? Each Sub ID Indicates the Beginning Value in a Range ? The Ending Value Is One Less Than the Beginning Value of the Next Sub ID 來(lái)自 Example Sub Ids Sub Mask Network ID Host Range 00000000 = 0 00100000 = 32 01000000 = 64 01100000 = 96 10000000 = 128 10100000 = 160 11000000 = 192 11100000 = 224 TOTAL 6 SUBNETS 8190 HOSTS PER SUBNET Netword ID FROM ISP No. of Network = 1 SUBNET MASK No. of Hosts = 65534 (2^162) We need 6 Subs 255 255 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 224 。來(lái)自 Inter Protocol 來(lái)自 Overview TCP/IP and the DoD Model IP Addressing Subting 來(lái)自 TCP/IP and the DoD Model Comparison of Dod and OSI Model The TCP/IP protocol suite The Process / Application layer Protocols The HosttoHost Layer Protocols The Inter