電腦筆記本: Primary Vs Preferred

2014年7月1日星期二

Primary Vs Preferred

在Juniper 網路設備中，都會有在interface上設定IP位址後，可設定一個參數(primary or perferred)

根據官方的解釋:

Configuring the Primary Address for an Interface

The primary address on an interface is the address that is used by default as the local address for broadcast and multicast packets sourced locally and sent out the interface. For example, the local address in the packets sent by a ping interface so-0/0/0.0 255.255.255.255 command is the primary address on interface so-0/0/0.0. The primary address flag also can be useful for selecting the local address used for packets sent out unnumbered interfaces when multiple non-127 addresses are configured on the loopback interface, lo0. By default, the primary address on an interface is selected as the numerically lowest local address configured on the interface.

To set a different primary address, include the primary statement:

primary;

You can include this statement at the following hierarchy levels:

[edit interfaces interface-name unit logical-unit-number family family address address]
[edit logical-systems logical-system-name interfaces interface-name unit logical-unit-number family family address address]

Configuring the Preferred Address for an Interface

The preferred address on an interface is the default local address used for packets sourced by the local routing platform to destinations on the subnet. By default, the numerically lowest local address is chosen. For example, if the addresses 172.16.1.1/12, 172.16.1.2/12, and 172.16.1.3/12 are configured on the same interface, the preferred address on the subnet (by default, 172.16.1.1) would be used as a local address when you issue a ping 172.16.1.5 command.
To set a different preferred address for the subnet, include the preferred statement:

preferred;

You can include this statement at the following hierarchy levels:

[edit interfaces interface-name unit logical-unit-number family family address address]
[edit logical-systems logical-system-name interfaces interface-name unit logical-unit-number family family address address]