User Manual

370
Users Manual of XGS-6350-24X4C
needed to connect the physical network. In this case, you can configure the subordinate IP address on the
switch or the server, enabling two logical subnets to use the same physical subnet. Most of early-stage
networks which are based on the layer-2 bridge are not divided into multiple subnets. You can divide the
early-stage network into multiple route-based subnets by correctly using the subordinate IP addresses.
Through the configured subordinate IP addresses, the routing switch in the network can know multiple
subnets that connect the same physical network.
 If two subnets in one network are physically separated by another network.
In this case, you can take the address of the network as the subordinate IP address. Therefore, two subnets
in a logical network that are physically separated, therefore, are logically connected together.
If you configure a subordinate address for a routing switch in a network segment,
you need to do this for other routing switches in the same network segment.
Run the following command in interface configuration mode to configure multiple IP addresses on the network
interface.
Run… To…
ip addressip-address mask
secondary
Configure multiple IP addresses on the
network interface.
When the IP routing protocol is used to send the route update information,
subordinate IP addresses may be treated in different ways.
43.1.3.3 Configuring Address Resolution
IP can realize functions such as IP address resolution control. The following sections show how to configure
address resolution:
1. Creating address resolution
An IP device may have two addresses: local address (local network segment or device uniquely identified
by LAN) and network address (representing the network where the device is located). The local address is the
address of the link layer because the local address is contained in the message header at the link layer, and is
read and used by devices at the link layer. The professionalists always call it as the MAC address. This is
because the MAC sub layer in the link layer is used to process addresses.
For example, if you want your host to communicate with a device on Ethernet, you must know the 48-bit MAC
address of the device or the local address of the link layer. The process on how to obtain the local address of
the link layer from the IP address is called as Address Resolution Protocol (ARP). The process on how to
obtain the IP address from the local address of the link layer is called as Reverse Address Resolution
(RARP).
Our system adopts address resolution in two types: ARP and proxy ARP. The ARP and proxy ARP are
defined in RFC 860 and 1027 respectively.