Network topology architectures and TCP&UDP Subnetting P-2
Network topology architectures
Bus Topology
Bus topology is also called as point–to–multi–point arrangement. In a bus topology, all nodes or devices are linked with one transmitter or server computer via a single cable (mostly coaxial cable) called Backbone. All nodes are connected to the bus cable by drop lines. A drop line is a connection running between the nodes and the main cable
Star Topology
Ring Topology
In a ring topology, each node has a dedicated point–to–point line configuration only with the two nodes on either side of it. A signal is passed along the ring in one direction, from node to node, until it reaches its receiver. Each node in the ring is integrated as a repeater. When a node receives a signal intended from another node, its repeater regenerates the bits and passes them along.
Mesh Topology.
In a mesh topology, each node has a dedicated point–to–point connection with rest of the nodes in the network. Dedicated connection means data can only be flown between two nodes, it connects.
Hybrid Topology
This topology is a common arrangement of two or more topologies described above. It means two or more above described topologies connected with each other to form a hybrid network arrangement.
Tree Topology
Tree topology is a combination of one or more star topology arrangements. All the sub-central hubs are connected to a main central hub to form a tree topology. A cable TV network is a good example of this type of topology.
Peer–to–Peer (point-to-point link)
Each point–to–point link contains one transmitter and one receiver. Each station receives data exactly from one transmitter and each transmitter transmits data to exactly one receiver. Receiving and transmission process can be done over a single wire or can use separate wires for better performance.
Physical interface
Physical interfaces consist of a software driver and a connector into which you connect network media, such as an Ethernet cable. Physical interfaces can be grouped for administrative or availability purposes.
Cabling types
Fiber cables
Power Over Ethernet (POE)
Cisco Catalyst switches perform role of Power Sourcing Equipment (PSE). Cisco IP Phones, Access Points and other end devices are Powered Devices (PDs). Standards and data sheets usually list 2 power values:
- Delivered on the switch port (PSE)
- Received at the end device (PD)
The value at PD is always smaller than at PSE due to the power dissipation in cabling.
Compare TCP to UDP
TCP is a connection-oriented protocol and UDP is a connection-less protocol. TCP establishes a connection between a sender and receiver before data can be sent. UDP does not establish a connection before sending data.
TCP UDP
| Transmission Control Protocol | User Datagram Protocol or Universal Datagram Protocol |
| Transmission Control Protocol is a connection-oriented protocol. | User Datagram Protocol is a connectionless protocol. |
| HTTP, HTTPs, FTP, SMTP, Telnet | DNS, DHCP, TFTP, SNMP, RIP, VOIP. |
| TCP rearranges data packets in the order specified. | UDP has no inherent order as all packets are independent of each other. If ordering is required, it has to be managed by the application layer. |
| The speed for TCP is slower than UDP. | UDP is faster because error recovery is not attempted. It is a "best effort" protocol. |
| There is absolute guarantee that the data transferred remains intact and arrives in the same order in which it was sent. | There is no guarantee that the messages or packets sent would reach at all. |
| TCP header size is 20 bytes | UDP Header size is 8 bytes. |
| Source port, Destination port, Check Sum | Source port, Destination port, Check Sum |
| Data is read as a byte stream, no distinguishing indications are transmitted to signal message (segment) boundaries. | Packets are sent individually and are checked for integrity only if they arrive. Packets have definite boundaries which are honored upon receipt, meaning a read operation at the receiver socket will yield an entire message as it was originally sent. |
| Acknowledgement segments | No Acknowledgment |
| SYN, SYN-ACK, ACK | No handshake (connectionless protocol) |
Configure and verify IPv4 addressing
Address types
Unicast
Broadcast
Multicast
VLSM
Unicast
Broadcast
Multicast
VLSM
In the IP version 4, every TCP/IP hosts are identified by the logical IP address. This IP address is the network layer address and also has no dependence on a Data link layer address. The unique IP address is necessary for the each network component and host which communicates with the help of TCP/IP and also can be allotted manually or with the help of DHCP. The types of the IPv4 addresses are unicast, multicast, broadcast and VLSM described below.
Unicast
Unicast is the very most common form of the IP address. The unicast address is the address which identifies the unique node on the network. The unicast addressing available in the IPv4 typically implies to a single receiver or a single sender, however, it can be used in the both receiving and sending.
In this Unicast mode, the data is sent only to the one destined host. A destination address field is comprised of 32 bits of the IP address of a destination host. Take the example of the above figure, the client sends the data to a targeted server only. The internet standard defines the Unicast IPv4 addresses as the "assigned to the single network interface which is located on the particular subnet on a network and also used for the one to one communication". Every IPv4 unicast address has a host ID and a network ID.
The network ID is also called as the network address. It is fixed portion of the IPv4 unicast address which identifies a set of interface which is located on the same logical or physical network segment like bounded by the IPv4 routers. The network segment on the TCP/IP networks are also called as the subnet. The entire system on the same logical or physical subnet has to use the same network ID only and the network ID has to be unique to the all TCP/IP network. Then the host ID is also called as the host address. It is the variable portion of the unicast address of the IPv4, which is used to verify the network interface of the node on the subnet. Then the host address has to be very unique to all the network of TCP/IP.
Broadcast
The IPv4 uses the set of the broadcast addresses to give the one to everyone on a subnet delivery service. The packets are sent to the IPv4 broadcast addresses which are processed by the entire interfaces on a subnet. As shown in the below figure, the packet is addressed to the entire hosts in the network segment. Then the destination address field comprises of typical broadcast address of 255.255.255.255. When the host identifies the packet on a network, then it is bound to process that. See the diagram, the client sends the packet that is used by all servers.
The internet standard defines the broadcast as " assigned to entire network interfaces which is located on the subnet on a network and also used for the one to everyone on the subnet communications". The IPv4 broadcast addresses are again classified into subnet broadcast, network broadcast, limited broadcast and all subnets-directed broadcast.
Multicast
The IPv4 multicast addresses are mostly used for the single packet of one-to-many delivery. On the multicast enabled IPv4 intranet, the IPv4 packet addressed to the IPv4 multicast addresses are forwarded by the routers to a subnet on which there is a host listening to a traffic sent to an IPv4 multicast address. The IPv4 multicast offers an effective one-to-many service of delivery of various types of communication. The IPv4 multicast addresses are the one which defined by a class D internet address.
In this type of addressing, it is a mix of the previous 3 modes. The packet sent is either destined to the single host, nor the entire host on a segment. In the packet, destination address comprises of the special address which begins with the 224.x.x.x and also can be used by more than 1 host to as shown in the above figure.
VLSM
The internet service provider will face the situation where they require to allocate the IP subnets of the different sizes as per the need of the customer. One user can ask for a class C subnet of the 3 IP addresses and some users can ask for the 10 IPs. For the ISP, it is tough to divide an IP addresses into the fixed size subnets, instead they may like the subnets which results in the minimum wastage of the IP addresses. For that, the VLSM offers greater space and opportunity for at all.
The VLSM stands for the variable length subnet masking. This Subnetting is very similar to the traditional subnetting in which bits are borrowed to make the subnets. The subnetting is not the single pass activity. The VLSM is the technique which allows the network administrator to divide the IP address space into the subnets of various sizes, that is according to an individual requirements of the every network, unlike the simple same size of subnetting. On the other hand, the VLSM is simply the subnetting a subnet.
Review the above diagram, the starting address space in the subnetting scenario - 3 is not the whole classful address. It is the subnet 5 from the subnetting scenario two. Take the above diagram as an example for the VLSM topology with an address space as 172.10.5.0/22 as well as the network needs as same as in the diagram. Apply the addressing scheme which conserves the huge amount of the addresses for the future growth. Actually, it is important to have 5 subnets: 1 WAN subnet and 4 LAN subnets. Beginning with the huge host requirement on the LAN 3, start subnetting an address space. To satisfy 250 hosts need, then leave 8 hosts bits. Because 10 hosts bits are there in total and borrow 2 bits to make the first round of the subnets. The beginning subnet mask is the 255.255.252.0 or /22. Here the multiplier is one. The 4 subnets are
Assigning the subnet 0 to LAN 3, they are left with the three /24 subnets. By continuing onto the next huge host need on the LAN 4. Then take the subnet 1, 172.10.6.0/21 and also subnet it further more by using the same technique.
SubNetting
A subnetwork or subnet is a logical subdivision of an IP network. The practice of dividing a network into two or more networks is called subnetting. Computers that belong to a subnet are addressed with an identical most-significant bit-group in their IP addresses.
Need for private IPv4 addressing
Private IPs were originally meant as a more secure means of providing IPv4 addresses to devices because private IPs are not routable over the internet. ... You do have to turn them into some sort of public address if you want to route over the internet. That could be via a public IPv4 or IPv6 address.
“172” and the “192” address ranges are designated for private use. The remaining addresses are considered “public,” and thus are routable on the global Internet.
we are using 192.168. X.X IP addresses because this is best practice. The IETF has created three IP ranges for private networks, with Class C being the smallest and easiest to control and maintain. This is why most routers use exactly this IP range.
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