Multiprotocol Routing Services
Protocol Configuration Reference
Version 3.3 Volume 1

Configuring and Monitoring DVMRP

This chapter describes configuring and monitoring for DVMRP (Distance Vector Multicast Routing Protocol) protocol activity. It includes the following sections:

• "Accessing the DVMRP Configuration Environment"

• "DVMRP Configuration Commands"

• "DVMRP Monitoring Commands"

Accessing the DVMRP Configuration Environment

To access the DVMRP configuration environment, enter the following command at the Config> prompt:

   Config> protocol dvmrp
   Distance Vector Multicast Routing Protocol config monitoring
   DVMRP Config>

DVMRP Configuration Commands

This section describes the DVMRP configuration commands. The commands are entered at the DVMRP Config> prompt.

Table 27. DVMRP Configuration Commands Summary

Command	Function
? (Help)	Displays all the commands available for this command level or lists the options for specific commands (if available). See "Getting Help".
Add	Adds to already existing DVMRP information. You can add a physical interface or an IP-IP tunnel interface.
Change	Changes DVMRP information in SRAM. You can change the cost or threshold of a physical interface, IP-IP tunnel, the MOSPF interface, or the endpoints of an IP-IP tunnel.
Delete	Deletes DVMRP information from the static configuration.
Disable	Disables the entire DVMRP protocol or the MOSPF interface.
Enable	Enables the entire DVMRP protocol or the MOSPF interface.
List	Displays the DVMRP configuration.
Exit	Returns you to the previous command level. See "Exiting a Lower Level Environment".

Add

Use the add command to add to existing DVMRP information. You can add a physical interface or an IP-IP tunnel.

Syntax:

add

interface ip-address cost threshold

 

tunnel tunnel-source tunnel-destination cost threshold

interface

Adds or updates a DVMRP interface

ip-address

Specifies the IP address of the DVMRP interface.

Valid Values: Any valid IP address

Default Value: None

cost

Specifies the cost (in terms of hop-count) incurred for using the interface.

Valid Values: Any integer greater than 0

Default Value: 1

threshold

Specifies the time-to-live needed to reach the nearest neighbor on the interface.

Valid Values: Any integer greater than 0

Default Value: 1

tunnel

Adds or updates an IP-IP tunnel across a non-multicast network. Tunnels need to be configured when multicast traffic needs to traverse a network which does not support multicast datagrams or are not running a multicast routing protocol.

source-address

Specifies the IP address of the tunnel source.

Valid Values: Any valid IP address

Default Value: None

destination-address

Specifies the IP address of the tunnel destination.

Valid Values: Any valid IP address

Default Value: None

cost

Specifies the cost (in terms of hop-count) incurred for using the tunnel.

Valid Values: Any integer greater than 0

Default Value: 1

threshold

Specifies the time-to-live needed to reach the nearest neighbor on the interface.

Valid Values: Any integer greater than 0

Default Value: 1

Change

Use the change command to modify existing DVMRP information. You can modify the cost or threshold values of physical interface, IP-IP tunnels, or the MOSPF interface.

Syntax:

change

interface ip-address cost threshold

 

tunnel tunnel-source tunnel-destination cost threshold

 

mospf cost threshold

interface

Changes a DVMRP interface

ip-address

Valid Values: Any valid IP address

Default Value: None

cost

Specifies the cost (in terms of hop-count) incurred for using the interface.

Valid Values: Any integer greater than 0

Default Value: 1

threshold

Specifies the time-to-live needed to reach the nearest neighbor on the interface.

Valid Values: Any integer greater than 0

Default Value: 1

tunnel

Changes an IP-IP tunnel.

source-address

Valid Values: Any valid IP address

Default Value: None

destination-address

Valid Values: Any valid IP address

Default Value: None

cost

Specifies the cost (in terms of hop-count) incurred for using the interface.

Valid Values: Any integer greater than 0

Default Value: 1

threshold

Specifies the time-to-live needed to reach the nearest neighbor on the interface.

Valid Values: Any integer greater than 0

Default Value: 1

mospf

Changes a MOSPF interface.

cost

Specifies the cost (in terms of hop-count) incurred for using the interface.

Valid Values: Any integer greater than 0

Default Value: 1

threshold

Specifies the time-to-live needed to reach the nearest neighbor on the interface.

Valid Values: Any integer greater than 0

Default Value: 1

Delete

Use the delete command to remove existing DVMRP information from static memory.

Syntax:

delete

interface ip-address

 

tunnel tunnel-source tunnel-destination

interface

Deletes a DVMRP interface.

ip-address

Valid Values: Any valid IP address

Default Value: None

tunnel

Deletes an IP-IP tunnel.

source-address

Valid Values: Any valid IP address

Default Value: None

destination-address

Valid Values: Any valid IP address

Default Value: None

Disable

Use the disable command to disable the entire DVMRP protocol or the MOSPF interface.

Syntax:

disable

dvmrp

 

mospf

dvmrp

Disables the DVMRP protocol. When disabled, the device will not participate as a DVMRP multicast router.

mospf

Disables the interface to the MOSPF routing protocol. When disabled, the DVMRP protocol will not forward/receive multicast datagrams to/from the MOSPF routing protocol.

Enable

Use the enable command to enable the entire DVMRP protocol or the MOSPF interface.

Syntax:

enable

dvmrp

 

mospf cost threshold

dvmrp

Enables the DVMRP protocol. All interfaces configured for IP and do not have MOSPF enabled on them, and the MOSPF interface are enabled.

mospf

Enables the interface to the MOSPF routing protocol for DVMRP. This interface allows DVMRP to forward multicast datagrams to the MOSPF routing protocol. This interface is treated as a physical interface.

cost

Specifies the cost (in terms of hop-count) incurred for using the interface.

Valid Values: Any integer greater than 0

Default Value: 1

threshold

Specifies the time-to-live needed to reach the nearest neighbor on the interface.

Valid Values: Any integer greater than 0

Default Value: 1

List

Use the list command to display the current DVMRP configuration. The output displays the current DVMRP state (disabled or enabled), physical interface configuration information, tunnel configuration information, and MOSPF configuration information.

Syntax:

list

Example:

DVMRP config> list
           
           DVMRP on
           phyint 128.185.138.19 1 1
           phyint 128.185.177.19 2 4
           tunnel 128.185.138.19 128.185.138.21 4 4
 

The following information are displayed for each listed interface:

DVMRP protocol

Displays whether DVMRP is enabled or disabled

DVMRP physical interfaces

For each physical interface, its IP address and values for cost and threshold are displayed.

DVMRP tunnel interfaces

For each tunnel interface, the configured tunnel endpoints, cost and threshold are displayed.

DVMRP MOSPF interface

For the MOSPF interface, cost and threshold are displayed.

DVMRP Monitoring Commands

The DVMRP monitoring commands allow you to view the parameters and statistics of networks that have enabled DVMRP.

Enter the DVMRP monitoring commands at the DVMRP> prompt.

Table 28. DVMRP Monitoring Command Summary

Command	Function
? (Help)	Displays all the commands available for this command level or lists the options for specific commands (if available). See "Getting Help".
Dump routing tables	Displays the DVMRP routes contained in the routing table.
Interface summary	Displays DVMRP interface statistics and parameters.
Join	Configures the router to belong to one or more multicast groups.
Leave	Removes the router from membership in multicast groups.
Mcache	Displays a list of currently active multicast forwarding cache entries.
Mgroups	Displays the group membership of the router's attached interfaces.
Mstats	Displays various multicast routing statistics.
Exit	Returns you to the previous command level. See "Exiting a Lower Level Environment".

Dump Routing Tables

Use the dump routing tables command to display the set of known DVMRP multicast sources. Each source is listed together with the DVMRP router it was learned from, an associated cost, and the number of seconds since the routing table entry was refreshed.

Syntax:

dump

Example: dump

            Multicast Routing Table
            Type   Origin-Subnet   From-Gateway    Metric  Age  In  Out-Vifs
            Direct 18.26.0.0       192.35.82.97      10     30   1    0  2*
            Direct 18.58.0.0       192.35.82.97       4     30   1    0  2*
            DVMRP  18.85.0.0       192.35.82.97       4     30   1    0  2*
            DVMRP  18.180.0.0      192.35.82.97       3     30   1    0  2*
            DVMRP  36.8.0.0        192.35.82.97       9     30   1    0  2*
            DVMRP  36.56.0.0       192.35.82.97       7     30   1    0  2*
            DVMRP  36.103.0.0      192.35.82.97       9     30   1    0  2*
            DVMRP  128.61.0.0      192.35.82.97       8     30   1    0  2*
            DVMRP  128.89.0.0      192.35.82.97      10     30   1    0  2*
            DVMRP  128.109.0.0     192.35.82.97       4     30   1    0  2*
            DVMRP  128.119.0.0     192.35.82.97       4     30   1    0  2*
            DVMRP  128.150.0.0     192.35.82.97       6     30   1    0  2*

Type

Displays the type of multicast sources (i.e., DVMRP)

Origin-Subnet

Displays the IP address of the originating subnet.

From-Gateway

Displays the IP address of the gateway from which the entry came.

Metric

Displays the associated cost of that route.

Age

Displays the age of routing table entry as the number of seconds since the routing table entry was refreshed.

In

Displays the DVMRP VIF that multicast datagram from the source must be received on.

Out-Vifs

Displays those VIFs that will send the multicast datagrams. VIFs marked with an asterisk indicate that a datagram will only be forwarded if there are group members on the attached network.

Interface Summary

Use the interface summary command to display current list of DVMRP interfaces (or VIFs).

Syntax:

interface interface-ip-address

Example: interface

            Virtual Interface Table
            Vif  Local-Address                            Metric  Thresh  Flags
            0   10.1.153.22      subnet: 10.1.153.0         1       1    querier
            1   10.1.154.22      subnet: 10.1.154.0         1       1    down

Vif

Displays the number assigned to DVMRP interfaces (or VIFs). Each VIF is assigned a number, which is used to identify the VIF in other commands.

Local Address

Displays the local IP address of the DVMRP interface.

Metric

The associated cost of the route.

Threshold

Reflects the ability of a network to control external flow of multicast packets outside of the network.

Flags

Displays whether the VIF is down or that the router is the sender of IGMP Host Membership Queries on the interface.

Join

Use the join command to establish the router as a member of a multicast group.

This command is similar to the join command in the OSPF configuration monitoring with two differences:

• The effect on group membership is immediate when the commands are given from the monitor (i.e., a restart/reload is not required).

• The command keeps track of the number of times a particular group is "joined."

When the router is the member of a multicast group, it responds to pings and SNMP queries sent to the group address.

Syntax:

join multicast-group-address

Example: join 224.185.00.00

Leave

Use the leave command to remove a router's membership in a multicast group. This will keep the router from responding to pings and SNMP queries sent to the group address.

This command is similar to the leave command in the OSPF configuration monitoring with two differences:

• The effect on group membership is immediate when the commands are given from the monitor (i.e., a restart/reload is not required).

• The command will not delete group membership until the "leaves" executed equals the number of "joins" previously executed.

Syntax:

leave multicast-group-address

Example: leave 224.185.00.00

Mcache

Use the mcache command to display a list of currently active multicast cache entries. Multicast cache entries are built on demand, whenever the first matching multicast datagram is received. There is a separate cache entry (and therefore a separate route) for each datagram source network and destination group combination.

Cache entries are cleared on topology changes (e.g., a point-to-point line in the DVMRP system going up or down), and on group membership changes.

Note:

The numbers displayed in the legend at the top of the output do NOT refer directly to VIFs, but instead refer to physical interfaces (which may be running either DVMRP or MOSPF) and tunnels.

Note:

Syntax: mcache   Example: mcache 0: Eth/0 1: TKR/0 2: Internal 3: 128.185.246.17 4: 192.35.82.97 Source Destination Count Upst Downstream 128.185.146.0 239.0.0.1 1 0 2,4 128.119.0.0 224.2.199.198 9 4 3 128.9.160.0 224.2.127.255 1 4 3 13.2.116.0 224.2.0.1 27 4 3 140.173.8.0 224.2.0.1 31 4 3 128.165.114.0 224.2.0.1 25 4 3 132.160.3.0 224.2.158.99 11 4 3 132.160.3.0 224.2.170.143 56 4 3 128.167.254.0 224.2.199.198 27 4 3 129.240.200.0 224.2.0.1 21 4 3 131.188.34.0 224.2.0.1 28 4 3 131.188.34.0 224.2.199.198 28 4 3 Source Source network/subnet of matching datagrams. Destination Destination group of matching datagrams. Count Displays the number of entries processed for that multicast group. Upstream Displays the neighboring network/router from which the datagram must be received in order to be forwarded. When this reads as "none", the datagram will never be forwarded. Downstream Displays the total number of downstream interfaces/neighbors to which the datagram will be forwarded. When this is none, the datagram will not be forwarded. There is more information in a multicast forwarding cache entry. A cache entry can be displayed in detail by providing the source and destination of a matching datagram on the command line. If a matching cache entry is not found, one is built. A sample of this command is shown below: Example: mcache 128.185.182.9 224.0.1.2 source Net: 128.185.182.0 Destination: 224.0.1.2 Use Count: 472 Upstream Type: Transit Net Upstream ID: 128.185.184.114 Downstream: 128.185.177.11 (TTL = 2) In addition to the information shown in the short form of the mcache command, the following fields are displayed: Upstream Type Indicates the type of node from which the datagram must be received to be forwarded. Possible values for this field are "none" (indicating that the datagram will not be forwarded), "router" (indicating that the datagram must be received over a point-to-point connection), "transit network", "stub network", and "external" (indicating that the datagram is expected to be received from another Autonomous System). Downstream Prints a separate line for each interface or neighbor to which the datagram will be sent. A TTL value is also given, indicating that datagrams forwarded out of or to this interface must have at least the specified TTL value in their IP header. When the router is itself a member of the multicast group, a line specifying internal application appears as one of the downstream interfaces/neighbors.

Mgroups

Use the mgroups command to display the group membership of the router's attached interfaces. Only the group membership for those interfaces on which the router is either designated router or backup designated router are displayed.

Syntax:

mgroups

 

Example:

mgroups
Local Group Database
Group             Interface                 Lifetime (secs)
 
224.0.1.1         128.185.184.11 (Eth/1)       176
224.0.1.2         128.185.184.11 (Eth/1)       170
224.1.1.1         Internal                     1

Group

Displays the group address as it has been reported (via IGMP) on a particular interface.

Interface

Displays the interface address to which the group address has been reported (via IGMP).

The router's internal group membership is indicated by an value of "internal". For these entries, the lifetime field (see below) indicates the number of applications that have requested membership in the particular group.

Lifetime

Displays the number of seconds that the entry will persist if Membership Reports cease to be heard on the interface for the given group.

Mstat

Use the mstat command to display various multicast routing statistics. The command indicates whether multicast routing is enabled and whether the router is an inter-area and/or inter-AS multicast forwarder.

Syntax:

mstats

 

Example:

mstats
              MOSPF forwarding:       Enabled
              Inter-area forwarding:  Enabled
              DVMRP forwarding:       Enabled
 
Datagrams received:           45476  Datagrams (ext source):    0
Datagrams fwd (multicast):        0  Datagrams fwd (unicast):   0
Locally delivered:                0  No matching rcv interface: 0
Unreachable source:               4  Unallocated cache entries: 0
Off multicast tree:               0  Unexpected DL multicast:   0
Buffer alloc failure:             0  TTL scoping:               0
 
# DVMRP routing entries:          0  # DVMRP entries freed:     0
# fwd cache alloc:                5  # fwd cache freed:         0
# fwd cache GC:                   0  # local group DB alloc:    6
# local group DB free:            0
 

MOSPF forwarding

Displays whether the router will forward IP multicast datagrams.

Inter-area forwarding

Displays whether the router will forward IP multicast datagrams between areas.

DVMRP forwarding

Displays whether the router will forward IP multicast datagrams.

Datagrams received

Displays the number of multicast datagrams received by the router (datagrams whose destination group lies in the range 224.0.0.1 - 224.0.0.255 are not included in this total).

Datagrams (ext source)

Displays the number of datagrams that have been received whose source is outside the AS.

Datagrams fwd (multicast)

Displays the number of datagrams that have been forwarded as datalink multicasts (this includes packet replications, when necessary, so this count could very well be greater than the number received).

Datagrams fwd (unicast)

Displays the number of datagrams that have been forwarded as datalink unicasts.

Locally delivered

Displays the number of datagrams that have been forwarded to internal applications.

No matching rcv interface

Displays the count of those datagrams that were received by a non-inter-AS multicast forwarder on a non-MOSPF interface.

Unreachable source

Displays a count of those datagrams whose source address was unreachable.

Unallocated cache entries

Displays a count of those datagrams whose cache entries could not be created due to resource shortages.

Off multicast tree

Displays a count of those datagrams that were not forwarded either because there was no upstream neighbor or no downstream interfaces/neighbors in the matching cache entry.

Unexpected DL multicast

Displays a count of those datagrams that were received as datalink multicasts on those interfaces that have been configured for datalink unicast.

Buffer alloc failure

Displays a count of those datagrams that could not be replicated because of buffer shortages.

TTL scoping

Indicates those datagrams that were not forwarded because their TTL indicated that they could never reach a group member.

DVMRP routing entries:

Displays the number of DVMRP routing entries.

DVMRP entries freed:

Indicates the number of DVMRP entries that have been freed. The size will be the number of routing entries minus the number of entries freed.

# fwd cache alloc

Indicates the number of cache entries allocated. The current forwarding cache size is the number of entries allocated ("# fwd cache alloc") minus the number of cache entries freed ("# fwd cache freed").

# fwd cache freed

Indicates the number of cache entries freed. The current forwarding cache size is the number of entries allocated ("# fwd cache alloc") minus the number of cache entries freed ("# fwd cache freed").

# fwd cache GC

Indicates the number of cache entries were cleared because they were not recently used and the cache overflowed.

# local group DB alloc

Indicates the number of local group database entries allocated. The number allocated ("# local group DB alloc") minus the number freed ("# local group DB free") equals the current size of the local group database.

# local group DB free

Indicates the number of local group database entries freed. The number allocated ("# local group DB alloc") minus the number freed ("# local group DB free") equals the current size of the local group database.

The number of cache hits can be calculated as the number of datagrams received ("Datagrams received") minus the total of datagrams discarded due to "No matching rcv interface," "Unreachable source" and "Unallocated cache entries", and minus "# local group DB alloc." The number of cache misses is simply "# local group DB alloc"+.