Black Box LRU4240 manual Auto-cost, Dual Trunk E1 Router User’s Guide Technical 0118 96 56 165

Dual Trunk E1 Router

INTERVAL=dead-intervalhello-intervalretransmit-intervaltransmit-delay VALUE VALUE = <1-65535> The number of seconds in the delay or interval.

hello-interval= The interval the router waits before it sends a hello packet. The default is ten seconds. retransmit-interval= The interval the router waits before it retransmits a packet. The default is five seconds.

transmit-delay= The interval the router waits before it transmits a packet.The default value is one second.

dead-interval= The interval during which no packets are received and after which the router considers a neighboring router as off-line. The default is 40 seconds.

Command Mode

Router mode.

Usage

In OSPF, all non-backbone areas must be connected to a backbone area. If the connection to the backbone is lost, the virtual link repairs the connection.

You can configure virtual links between any two backbone routers that have an interface to a common non-backbone area. The protocol treats these two routers joined by a virtual link as if they were connected by an unnumbered point-to-point network.To configure virtual link, include both the transit area ID and the corresponding virtual link neighbor's router ID in the virtual link neighbor. To see the router ID use the show ip ospf command.

Configure the Hello-interval to be the same for all routers attached to a common network. If the hello-interval is short, the router detects topological changes faster, but more routing traffic follows. Retransmit-interval is the expected round-trip delay between any two routers in a network. Set the value to be greater than the expected round-trip delay to avoid needless retransmissions.

Transmit-delay is the time taken to transmit a link state update packet on the interface.Before transmission, the link state advertisements in the update packet, are incremented by this amount. Set the transmit-delay to be greater than zero. Also, take into account the transmission and propagation delays for the interface.

Include the transit area ID and the corresponding virtual link neighbor's router ID in each virtual link neighbor to properly configure a virtual link.

Examples (note some examples show abbreviated parameters) area 123.123.123.1 virtual-link 123.123.123.2

area 123.123.123.1 virtual-link 123.123.123.2 authentication area 1 virtual-link 123.123.123.2 authentication null

area 1 virtual-link 1.1.1.1 hel 1 ret 2 tran 3 dead 4

Related Commands

area authentication, service password-encryption, show ip ospf

auto-cost

Use the auto-cost command to control how OSPF calculates default metrics for the interface.

Use the no form of this command to assign cost, based only on the interface type.

Command Syntax

auto-cost reference-bandwidth <1-4294967> no auto-cost reference-bandwidth

<1-4294967> The reference bandwidth in terms of Mbits per second. The default reference bandwidth is 100 Mbps.

Command Mode

Router mode

Usage

By default OSPF calculates the OSPF metric for an interface by dividing the reference bandwidth by the interface bandwidth. The default value for the reference bandwidth is 100Mbps. The auto-cost command is used to differentiate high bandwidth links. For multiple links with high bandwidth, specify a larger reference bandwidth value to differentiate cost on those links.

Examples

ospfd# configure terminal ospfd(config)# router ospf 100

ospfd(config-router)# auto-cost reference-bandwidth 50

Related Commands

ip ospf cost

Dual Trunk E1 Router User’s Guide TECHNICAL: 0118 96 56 000 165