Snmp Thresholds; Figure 2: Shared Local Address Pools - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - BROADBAND ACCESS CONFIGURATION GUIDE 2010-10-12 Configuration Manual

JunosE 11.3.x Broadband Access Configuration Guide
Example

SNMP Thresholds

54
A shared local address pool references one DHCP address pool. The shared local address
pool can then obtain addresses from the referenced DHCP address pool and from any
DHCP address pools that are linked to the referenced DHCP address pool.
Figure 2 on page 54 illustrates a shared local address pool environment that includes
four linked DHCP address pools. In the figure, both Shared_LAS_Pool_A and
Shared_LAS_Pool_B reference DHCP_Pool_1, and can therefore obtain addresses from
all four DHCP address pools. Shared_LAS_Pool_C references DHCP_Pool_3 and can get
addresses from DHCP_Pool_3 and DHCP_Pool_4.

Figure 2: Shared Local Address Pools

When the local address server requests an address from a shared address pool, the
address is returned from the referenced DHCP pool or a subsequent linked pool. If no
address is available, DHCP notifies the local address server and the search is ended.
Keep the following guidelines in mind when using shared local address pools:
The DHCP attributes do not apply to shared local address pools; for example, the lease
time for shared local address pools is infinite.
When you delete the referenced DHCP address pool, DHCP notifies the local address
server and logs out all subscribers that are using addresses from the deleted pool.
When you delete a shared local address pool, the local address server logs out the
subscribers that are using addresses from the deleted pool, then notifies DHCP and
releases the addresses.
If the chain of linked DHCP address pools is broken, no action is taken and the existing
subscribers retain their address. However, the DHCP local address pools that are no
longer part of the chain are now unable to provide any new addresses.
This following commands create the shared address pools in Figure 2 on page 54:
host1(config)#ip local shared-pool Shared_LAS_Pool_A DHCP_Pool_1
host1(config)#ip local shared-pool Shared_LAS_Pool_B DHCP_Pool_1
host1(config)#ip local shared-pool Shared_LAS_Pool_C DHCP_Pool_3
An address pool has SNMP thresholds associated with it that enable the local address
server to signal SNMP traps when certain conditions exist. These thresholds include high
utilization threshold and abated utilization threshold. If a pool's outstanding addresses
exceed the high utilization threshold and the SNMP trap signaling is enabled, SNMP is
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