Network illustrated tcpip phần 2 pptx

a datagram. With this option set, the points to which the datagram is routed are echoed back to the sender. This allows you to follow a datagram along a path. It is very often used in troubleshooting IP networks. If you have Windows 95, you have this utility. Type in (DOS prompt) “tracert <IP address>” and watch the echo points on your screen. IPv6 eliminated this field and those functions that were not used or were better implemented by other protocols. Previous Table of Contents Next [...]... the network With the first 2 bits reserved in a Class B (10xxxxxx) or 3 bits in a Class C (110xxxxx) address, the network numbers for Class B range from 128 .1.0.0 to 191 .25 5.0.0, and for Class C they range from 1 92. 1.1.0 to 22 3 .25 5 .25 5.0 Examples: 1 92. 1.1.1 20 0.6.5.4 150.150.5.6 9.6.7.8 128 .1.0.1 Node assigned with a host ID of 1, located on a Class C network of network 1 92. 1.1.0 Node assigned with... of the alphabet and therefore the network numdber is assigned the first byte • B is the second letter and therefore has the network number assigned to the first two byrtes • Class C is the third letter and therefore has thew network number assigned to the first three bytes The classes are Class A: 0– 127 Class B: 128 –191 Class C: 1 92 22 3 Class D: 22 3 23 9 Reserved: 24 0 25 4 Previous Table of Contents Next... mask for that IP address will be 25 5 .25 5 .24 8.0 in decimal This is the mask that we have assigned to the network address of 130.40.1 32. 3 We will always use 25 5 in the network potion of the subnet mask The 24 8 is used to tell the network station to use the first 5 bits (5 bits binary is 24 8 decimal) of the network address, not for a host ID, but for a subnet It tells a network station which bits to use... 3 bits of the third octet and 8 bits of the fourth octet) should be used for the host ID This allows for 32 subnets with 20 46 hosts on each subnet Therefore, the IP address of 130.40.1 32. 3, with a subnet mask of 25 5 .25 5 .24 8.0, yields the network number 130.40, subnet number 128 , and host ID 1 027 .64 Previous Table of Contents Next subnet numbering scheme, however, not actually part of the subnet number... we have 32 subnets on our network The Internet routing tables do not care about subnets We used one Class B network number and have 32 subnets available to us from the one Class B network Without subnetting, we would have one network number and up to 65,534 hosts assigned to it How did we get 32 possibilities? Using 5 bits for the subnet mask gives us 32 possible combinations (0 to 31), or 2n5 Remember,... Class C network of 20 0.6.5.0 Node assigned with a host ID of 5.6, located on a Class B network of 150.150.0.0 Node assigned with a host ID of 6.7.8, located on a Class A network of 9.0.0.0 Node assigned with a host ID of 0.1, located on a Class B network of 128 .1.0.0 Notice that to represent a network number only, only the network number is written The host field will be set to 0 This type of network. .. B Class C 1– 126 in the first field 128 –191 in the first field 1 92 22 3 in the first field Subnetting is the ability to move a mask over the bits normally associated with a host address and reclaim these bits as a subnet number The mask can use 22 bits for a Class A address, 14 bits for a Class B address, and 6 bits for a Class C address Previous Table of Contents Next “this” network (the network from... to the network, allowing a more efficient use of the address A few more things you need to consider: If the network station moves to a new network, does the IP address for that station change? Like the current telephone system, IP addresses must change when the network station is moved to a new network that employs a different network number If the network station is moved on the same logical network, ... network number display will become apparent when looking at routing tables Classful IP Address Review • In the first field: • Class A has the range of 1– 126 • Class B has the range of 128 –191 • Class C has the range of 1 92 22 3 • Class D has the range of 22 4 23 9 • Subnetting is the ability to place a mask over the host portion of the address to yield subnets • Allows for another level of hierarchy; efficient... throughout a single Class B assignment For example, if the network assignment is 130.1.0.0 and the subnet mask assigned is 25 5 .25 5 .25 5.0, the subnet mask must remain the same throughout the 130.1.0.0 network If the network address changes (for example, to 131.1.0.0), the subnet mask may also change for this new network number Subnet Restrictions RIP version 2 and OSPF do not have this restriction because they . therefore has thew network number assigned to the first three bytes. The classes are Class A: 0– 127 Class B: 128 –191 Class C: 1 92 22 3 Class D: 22 3 23 9 Reserved: 24 0 25 4 Previous Table. will be 25 5 .25 5 .24 8.0 in decimal. This is the mask that we have assigned to the network address of 130.40.1 32. 3. We will always use 25 5 in the network potion of the subnet mask. The 24 8 is used. allows for 32 subnets with 20 46 hosts on each subnet. Therefore, the IP address of 130.40.1 32. 3, with a subnet mask of 25 5 .25 5 .24 8.0, yields the network number 130.40, subnet number 128 , and host