Enterasys Networks CSX6000 - Manual (Page 343)

Central Site Remote Access Switch 343
C ONFIGURING IPX
IPX Triggered RIP/SAP
C ONFIGURATION E LEMENTS
D ATA B ASE T IMER
This timer starts when an update response is received. While this timer is running, the routes
learned from this router are still considered reachable, and advertised as such on other interfaces.
When this timer expires, the routes are considered unreachable and advertised as such until the
hold-down timer expires. Valid range for timer: 1 to 10,000 seconds; default: 180 seconds.
H OLD -D OWN T IMER
While this timer is running, unreachable routes are advertised on other interfaces. This timer starts
when:
•
the database timer for the route expires
• a formerly reachable route changes to unreachable in an incoming response
• a WAN circuit goes down
When this timer expires, and the unreachability information is communicated to all the reachable
WAN routers, this route is deleted. Valid range for timer: 1 to 10,000 seconds; default: 120 seconds.
R ETRANSMISSION T IMER
This timer starts when an update request (or response) packet is sent out. If acknowledgment is not
received by the time this timer expires, the packet is retransmitted. Valid range for timer: 1 to 10,000
seconds; default: 5 seconds.
M AXIMUM R ETRANSMISSIONS
This provides a limit on the number of retransmission attempts for an update request (or response)
packet. Maximum number supported: 10.
P OLLING T IMER
This is the frequency (in minutes) in which the next-hop WAN router is polled with update
requests, once the maximum retransmission count threshold is exceeded. Polling takes place only
when there is a physical connection; polling does not initiate its own connection. Valid range for
timer: 1 to 10,000 seconds (165 minutes); default: 5 minutes.
O VER - SUBSCRIPTION T IMER
Over subscription is the situation in which there are more next-hop routers on the WAN that need
updates than there are channels available. When a WAN circuit goes down, a delay (per the over-
subscription timer) is incorporated in marking the routes unreachable. This allows the calls to time-
multiplex over the limited channels. Valid range for timer: 1 to 10,000 seconds; default: 180 seconds.
T RIGGERED RIP/SAP B ACKGROUND I NFORMATION
When there are a large number of remote destinations, the manual configuration of static routes
and services over WAN circuits can pose a burden on system management. Yet running RIP/SAP
could also be problematic; since these are broadcast protocols, periodic broadcasts may not be
feasible due to cost and bandwidth considerations. Enabling the Triggered RIP/SAP feature allows
the CyberSWITCH to send information on the WAN only when there has been an update to the
database or a change in the reachability of a next-hop router.