DVMRP Router Commands

DVMRP Router Commands

Cisco does not support a full DVMRP implementation but does support a number of commands that affect DVRMP information that is being injected into the network. The DVMRP commands available are listed below with an explanation of their use. These commands are used when integrating PIM and DVMRP networks and are covered in more detail in Chapter 8, “PIM-DVMRP Networks.”

ip dvmrp unicast routing

Type: interface

This command allows Cisco routers to exchange DVMRP routing information. Routes received in a DVMRP report message are cached by the router in a DVMRP routing table. If PIM is running, then these routes will be preferred over routes in the unicast table.

ip dvmrp route-hog notification <route-count>

default--route-count = 10,000

Type: global

The route-hog notification command is used to send notification by way of a syslog message when the number of DVMRP routes has exceeded the route-count limit. There may be a misconfigured router on the MBONE, which is advertising a large number of routes.

ip dvmrp route-limit <route-count>

default--route-count = 7000

Type: global

The route-limit command limits the number of DVMRP routes advertised on a DVMRP-enabled interface. The interface could be a DVMRP tunnel, an interface with a DVMRP neighbor, or an interface configured with ip dvmrp unicast-routing. This command prevents injecting more routes than the route-count parameter into the MBONE.

ip dvmrp distance <administrative-distance>

Type: interface

This command sets the administrative distance for DVMRP routes to the value specified.

ip dvmrp metric <metric> [list <access-list>]

{[<protocol> <process-id>] | dvmrp]}

Type: interface

If PIM is configured on an interface and there are DVMRP neighbors, the router send DVMRP report messages. This command is used to set the metrics for unicast routes that are reported to the DVMRP neighbor. If an access-list is used, either standard or extended, then only those destinations permitted by the access-list will have the specified metric applied to the routes. The <protocol> <process-id> pair is used to limit the application of the metric to routes learned by the specified protocol. The DVMRP parameter is used to apply the metric only to routes from the DVMRP routing table. The command can be used multiple times on an interface.

ip dvmrp accept-filter <access-list> [neighbor-list <nbr-acl>] [<distance>]

Type: interface

This is used to filter incoming DVMRP reports. If the destination matches the <access-list> from neighbors in the <nbr-ac1>, then the routes are stored in the DVMRP routing table with <distance>.

ip dvmrp default-information originate | only

Type: interface

The default network 0.0.0.0 will be advertised to DVMRP neighbors on the interface with a default metric of 1. It only has effect if the neighbor is an mrouted 3.4 system. If the keyword only is used, then no other DVMRP routes will be reported. The keyword originate allows more specific routes to be advertised.

ip dvmrp metric-offset [in | out] <increment>

default: in

increment default: in 1 out 0

Type: interface

The value of increment is added to either incoming or outgoing DVMRP route reports.

ip dvmrp reject-non-pruners

Type: interface

If a DVMRP neighbor does not support pruning and grafting, then a neighbor relationship will not be established.

ip dvmrp summary-address <address> <mask> metric <value>

Type: interface

This configures a summary address to be advertised out of the interface.

ip dvmrp auto-summary

Type: interface

This enables DVMRP auto-summarization.

ip dvmrp output-report-delay <delay-time> [<burst>]

default: delay = 100 milliseconds burst = 2

Type: interface

This configures the interpacket delay between DVMRP reports in milliseconds. A set number of packets given by the burst parameter will be transmitted with a delay given by the delay-time parameter. cp6