Enterasys Networks CSX6000 manual Configuration Elements, Triggered RIP/SAP Background Information

CONFIGURING IPX

IPX Triggered RIP/SAP

CONFIGURATION ELEMENTS

DATABASE TIMER

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.

HOLD-DOWN TIMER

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.

RETRANSMISSION TIMER

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.

MAXIMUM RETRANSMISSIONS

This provides a limit on the number of retransmission attempts for an update request (or response) packet. Maximum number supported: 10.

POLLING TIMER

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.

OVER-SUBSCRIPTION TIMER

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.

TRIGGERED RIP/SAP BACKGROUND INFORMATION

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.

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