Win2000 IP Routing Application Analysis
Source: www.ccidnet.com
Windows 2000 Server routing provides multi-protocol LAN to LAN, LAN to WAN, virtual private network (
VPN) and Network Address Translation (NAT) Routing Services. Windows 2000 Server Routing has been familiar with routing protocols and services and system administrators using routing protocols (such as TCP / IPX, and AppleTalk).
Explain IP routing
In the usual term, the route is the process of forwarding the packet between the network. For TCP / IP-based networks, routing is a partial Internet Protocol (IP) combined with other network protocol services, providing the ability to forward each other between the hosts on a separate network segment based on the TCP / IP.
IP is the "post office" of the TCP / IP protocol, which is responsible for separating and delivering IP data. Each incoming or outgoing packet is called an IP datagram. The IP datagon contains two IP addresses: sending the source address of the host and the target address of the receiving host. Unlike the hardware address, the IP address inside the datagnet remains unchanged during the TCP / IP network. Routing is the main function of IP. By using the IP of the Internet layer, IP datagram is exchanged and processed on each host.
On the top of the IP layer, the transmission service on the source host uses the TCP segment or UDP message to the IP layer to the IP layer. The IP layer is assembled using the address information of the source and the target of the data on the network. The IP layer then transmits the datagram to the network interface layer. At this layer, the data link service converts IP datagrans to frames transmitted on a physical network. This process is performed in the opposite order on the target host. Each IP datagram contains the IP address of the source and target. The IP layer service on each host checks the target address of each datagram, comparing this address with the locally maintained routing table, and then determine the next forwarding operation. The IP router is connected to two or more IP network segments that can forward the packets.
IP router
The TCP / IP network segment is connected to each other by IP router. The IP router is a device that transmits IP datagrams from a network segment, which is called IP routing. The IP router connects two or more physically separated IP network segments. All IP routers have two basic characteristics:
1) IP router is a multi-hosted host. The multi-hosted host is a network host of each physical separated network segment with two or more network connection interfaces.
2) The IP router can forward the packet for other TCP / IP hosts.
There is an important difference between the IP router and other multi-hosted host: IP router must be able to forward IP-based network communication to other IP network hosts. Various possible hardware and software products can be used to implement IP routers. Based on hard-box routers, the hardware device that specifies the run special software is quite common. In addition, you can use the routing scheme based on software based on routing and remote access services (running on a computer running Windows 2000 Server).
Regardless of which type of IP router is used, all IP routes rely on the routing table communication between the network segments.
Routing table
TCP / IP host uses routing tables to maintain information about other IP networks and IP hosts. Network and host identify with IP addresses and subnet masks. In addition, since the routing table provides information about how to communicate with the remote network and host, the routing table is important.
For each computer on an IP network, you can use a project that communicates with the local computer to maintain the routing table. Usually this is not practical, so it can be used by default.
Gateway (IP router). When the computer is ready to send an IP datagram, it inserts its IP address and the recipient's target IP address to the IP header. Then the computer checks the target IP address, comparing it with the local maintained IP routing table, performs the corresponding operation according to the comparison result. The computer performs one of the following three operations:
• Report the Data to the protocol layer above the local host IP. · Make a network interface forwarding the datagram. · Discard the Data Newspaper. IP searches for routing with the target IP address in the routing table. From the most accurate route to the least accurate route, arrange them in the following order:
• Routing with the target IP address (host route). · Routing match with the network ID of the target IP address (network route). · The default route.
If the matching route is not found, IP discards the datagram.
Win 2000 IP routing table
Each computer running TCP / IP must decide the route. These decisions are controlled by IP routing tables. To display the IP routing table on a computer running Windows 2000, type Route Print on the command prompt line.
The following table is a typical example of the IP routing table. The computer in this example runs Windows 2000 with a network card and the following configuration:
IP address: 10.0.0.169 Subnet mask: 255.0.0.0 default gateway: 10.0.0.1
Note: The description in the first column above is actually not displayed in the output of the route print command.
The routing table is automatically created according to the current TCP / IP configuration of the computer. Each routing occupies a row in the table shown. The computer searches for items that are most matching with the target IP address in the routing table.
Description Network Target Network Mask Gateway Interface Jump Number The Number of Default Routing 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0127.0.0.0.0.0.0.0.0.0.0.0.0255.0.0.0.0.0.0.0.0255.0.0.0.0 .0.16910.0.0.1691 local ip address 10.0.0.169255.255.255.255127.0.0.1127.0.0.11 multicast address 224.0.0.0240.0.0.010.0.0.16910.0.0.1691 limited broadcast address 255.255.255.255255.255.255.25510.0 .0.16910.0.0.1691
If there is no other host or network routing, your computer will use the default route. The default route typically forwards the IP datagram (no match or clear local route) to the router of the local subnet.
On the gateway address. In the previous example, the default route forwards the datagram to
The gateway address is 10.0.0.1 router.
Due to the default
The router corresponding to the gateway contains information about the network ID of the large TCP / IP network internal other IP subnets, so it forwards the datagram to other routers until the datagram finally passes the IP router that is connected to the specified target host or subnet.
