H3C Technologies H3C S5560 Series Switches - Manual (Page 136)

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You can specify the preference for IP addresses advertised on a router interface.
An address with the minimum preference value (-2147483648) will not be used as a default gateway
address.
Lifetime of an IP address
An RA contains a lifetime field that specifies the lifetime of advertised IP addresses. If the host does not
receive a new RA for an IP address within the address lifetime, the host removes the route entry.
All the IP addresses advertised by an interface have the same lifetime.
Advertising interval
A router interface with IRDP enabled sends out RAs at a random interval between the minimum and the
maximum advertising intervals. This mechanism prevents the local link from being overloaded by a large
number of RAs sent simultaneously from routers.
H3C recommends that you shorten the advertising interval on a link that suffers high packet loss rates.
Destination address of RAs
An RA uses either of the following destination IP addresses:
• Broadcast address 255.255.255.255.
• Multicast address 224.0.0.1, which identifies all hosts on the local link.
By default, the destination IP address of an RA is the broadcast address. If all listening hosts support IP
multicast, specify 224.0.0.1 as the destination IP address.
Proxy-advertised IP addresses
By default, an interface advertises its primary and secondary IP addresses. You can specify IP addresses
of other gateways for an interface to proxy-advertise.
Protocols and standards
RFC 1256: ICMP Router Discovery Messages
Configuration procedure
To configure IRDP:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter interface view.
interface interface-type
interface-number The interface can be a Layer 3
Ethernet interface or VLAN interface.
3. Enable IRDP on the interface. ip irdp
By default, IRDP is disabled.
After IRDP is enabled on an interface,
the IRDP configuration takes effect,
and the device sends RA messages
out of the interface.