Alcatel-Lucent 7750 SR OS Service Manual page 1010

VPRN Service Configuration Commands
entry. Static hosts must be defined on the interface using the host command. Dynamic hosts are
enabled on the system through enabling lease-populate in the IP interface DHCP context. In the event
that both a static host and a dynamic host share the same IP and MAC address, the system's ARP
cache retains the host information until both the static and dynamic information are removed. Both
static and dynamic hosts override static ARP entries. Static ARP entries are marked as inactive when
they conflict with static or dynamic hosts and will be repopulated once all static and dynamic host
information for the IP address are removed. Since static ARP entries are not possible when static
subscriber hosts are defined or when DHCP lease state table population is enabled, conflict between
static ARP entries and the arp-populate function is not an issue.
The arp-populate command will fail if an existing static subscriber host on the SAP does not have
both MAC and IP addresses specified.
Once arp-populate is enabled, creating a static subscriber host on the SAP without both an IP
address and MAC address will fail.
arp-populate can only be enabled on VPRN interfaces supporting Ethernet encapsulation.
Use the no form of the command to disable ARP cache population functions for static and dynamic
hosts on the interface. All static and dynamic host information in the systems ARP cache will be
removed. Any existing static ARP entries previously inactive due to static or dynamic hosts will be
populated in the system ARP cache.
When arp-populate is enabled, the system will not send out ARP Requests for hosts that are not in
the ARP cache. Only statically configured and DHCP learned hosts are reachable through an IP
interface with arp-populate enabled.
Default
not enabled
arp-timeout
Syntax arp-timeout seconds
no arp-timeout
Context config>service>vprn>interface
config>service>vprn>sub-if>grp-if
Description
This command configures the minimum time in seconds an ARP entry learned on the IP interface will
be stored in the ARP table. ARP entries are automatically refreshed when an ARP request or
gratuitous ARP is seen from an IP host, otherwise, the ARP entry is aged from the ARP table. If arp-
timeout is set to a value of zero seconds, ARP aging is disabled.
The default value for arp-timeout is 14400 seconds (4 hours).
The no form of this command restores arp-timeout to the default value.
Default
14400 seconds
Parameters
seconds — The minimum number of seconds a learned ARP entry will be stored in the ARP table,
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expressed as a decimal integer. A value of zero specifies that the timer is inoperative and learned
ARP entries will not be aged.
Values
0 — 65535
7750 SR OS Services Guide