Table of Contents

DECnet Commands

Digital Equipment Corporation (Digital) developed the DECnet protocol to provide a way for its computers to communicate with one another. DECnet is currently in its fifth major product release called Phase V. DECnet Phase V is a superset of the OSI protocol suite, supports all OSI protocols, and is compatible with the previous release, Phase IV. DECnet Phase IV Prime supports inherent MAC addresses, which allow DECnet nodes to coexist with systems running other protocols that have MAC address restrictions. DECnet support on our routers includes local-area and wide-area DECnet Phase IV routing over Ethernet, Token Ring, FDDI, and serial lines (X.25, Frame Relay, SMDS).

Use the commands in this chapter to configure and monitor DECnet networks. For DECnet protocol configuration information and examples, refer to the "Configuring DECnet" chapter of the Router Products Configuration Guide.

access-list (standard)

To create a standard access list, use the access-list global configuration command. Use the no form of this command to delete the entire access list.

access-list access-list-number {permit | deny} source source-mask
no access-list

Syntax Description

Default

No access list is defined.

Command Mode

Global configuration

Usage Guidelines

In contrast with IP masks, a DECnet mask specification of "all ones" is entered as the decimal value 1023. In IP, the equivalent is 255.

Example

The following example sets up access list 300 to deny packets coming from node 4.51 and permit packets coming from 2.31:

Related Commands

access-list (extended)
access-list (filter connect initiate packets)
decnet access-group
decnet in-routing-filter
decnet out-routing-filter
show decnet interface

access-list (extended)

To create an extended access list, use the access-list global configuration command. Use the no form of this command to delete the entire access list.

access-list access-list-number {permit | deny} source source-mask [destination
destination-mask]
no access-list

Syntax Description

Default

No access list is defined.

Command Mode

Global configuration

Example

In the following example, access list 301 is configured to allow traffic from any host in networks 1 and 3. It implies no other traffic will be permitted. (The end of a list contains an implicit "deny all else" statement.)

Related Commands

access-list (standard)
access-list (filter connect initiate packets)
decnet access-group
decnet in-routing-filter
decnet out-routing-filter
show decnet interface

access-list (filter connect initiate packets)

To create an access list that filters connect initiate packets, use the access-list global configuration command. Use the no form of this command to disable the access list.

access-list access-list-number {permit | deny} source source-mask
[destination destination-mask {eq | neq} [[source-object] [destination-object]
[identification]] any]

no access-list

The optional argument source-object consists of the following string:

src [{eq | neq | gt | lt} object-number] [exp regular-expression] [uic [group, user]]

The optional argument destination-object consists of the following string:

dst [{eq | neq | gt | lt} object-number] [exp regular-expression] [uic [group, user]]

The optional argument identification consists of the following string:

[id regular-expression] [password regular-expression] [account regular-expression]

Syntax Description

See the "Regular Expressions" appendix for a description of regular expressions.

Default

No access list is defined.

Command Mode

Global configuration

Usage Guidelines

Depending upon the arguments you use, you can define access lists in three ways:

Use the source and source-mask arguments only.

Use the source, source-mask, destination, and destination-mask arguments.

Use the source, source-mask, destination, and destination-mask arguments, the eq | neq or any keywords and any or all of the following arguments: source-object, destination-object, and
identification.

Table 16-1 lists the DECnet object numbers.

Table 16-1   Common DECnet Object Numbers

Examples

The following example illustrates an access list for matching all connect packets for object
number 27:

The following example illustrates an access list for matching all connect packets except for the object number 17:

The following example illustrates an access list for matching all connect packets where the access identification was SYSTEM:

The following example illustrates an access list for matching all connect packets from area 1 to object number 27 (27 = VAX/VMS Personal Utility or MAIL) where SYSTEM is the originating user:

The following example illustrates an access list for matching any connect packet and can be used at the end of a list to permit any packets not already matched:

Related Commands

access-list (standard)
access-list (extended)
decnet access-group
decnet in-routing-filter
decnet out-routing-filter
show decnet interface

clear decnet counters

To clear DECnet counters that are shown in the output of the show decnet traffic EXEC command, use the clear decnet counters EXEC command.

clear decnet counters

Syntax Description

This command has no arguments or keywords.

Command Mode

EXEC

Example

The following example provides sample output of the clear decnet counters EXEC command:

Related Command

show decnet traffic

decnet access-group

To create a DECnet access group, use the decnet access-group interface configuration command.

decnet access-group access-list-number

Syntax Description

Default

No access group is defined.

Command Mode

Interface configuration

Example

The following example applies access list 389 to interface Ethernet 1:

Related Commands

access-list (standard)
show decnet interface

decnet advertise

To configure border routers to propagate Phase IV areas through an OSI backbone, use the decnet advertise global configuration command. To disable this feature, use the no form of this command.

decnet advertise decnet-area hops cost
no decnet advertise [decnet-area]

Syntax Description

Default

Disabled

Command Mode

Global configuration

Usage Guidelines

The output from the show decnet route EXEC command shows the cost and hop count for routes.

The decnet advertise command is used by border routers for propagating Phase IV areas through an OSI backbone.

The decnet advertise command and the clns route nsap-prefix discard command work together. When a router has DECnet Phase IV/V conversion enabled, any packet with the specified CLNS NSAP prefix causes CLNS to behave as if no route was found. That router then looks up the route to the border router that is advertising the Phase IV route. In turn, the router that is advertising the DECnet Phase IV route converts the packet to Phase V and sends it through the OSI cloud to the border router that is advertising the CLNS discard static route. Once it gets there, the packet is converted back to Phase IV.

The CLNS discard routes are created dynamically when the advertised adjacencies are propagated through the CLNS cloud. When a DECnet interface is disabled, the adjacencies are lost and the CLNS discard route is deleted. The DECnet area routing states are displayed in the output from the show decnet route EXEC command.

Example

The following example shows a partial use of the decnet advertise command:

Related Commands

A dagger () indicates that the command is documented in another chapter.

clns route discard
show decnet route

decnet area-max-cost

To set the maximum cost specification value for interarea routing, use the decnet area-max-cost global configuration command.

decnet [network-number] area-max-cost value

Syntax Description

Defaults

network-number: 0
value: 1022

Command Mode

Global configuration

Usage Guidelines

Make sure you have used the decnet node-type area global configuration command before using this command.

Example

In the following example, the node type is specified as area and the maximum cost is set to 500. Any route with a cost exceeding 500 will be considered unreachable by this router.

Related Commands

decnet area-max-hops
decnet node-type
show decnet interface

decnet area-max-hops

To set the maximum hop count value for interarea routing, use the decnet area-max-hops global configuration command.

decnet [network-number] area-max-hops value

Syntax

Description

Default

30 hops

Command Mode

Global configuration

Usage Guidelines

This command is only valid for area routers. Make sure you have issued the decnet node-type area global configuration command before using this command.

Example

The following example sets the router to be a Level 2 router, then sets a maximum hop count of 21:

Related Commands

decnet area-max-cost
decnet node-type
show decnet interface

decnet congestion-threshold

Use the decnet congestion-threshold interface configuration command to set the congestion- experienced bit if the output queue has more than the specified number of packets in it. A number value of zero or the no form of the command prevents this bit from being set. Use the no decnet congestion-threshold command to remove the parameter setting and set it to 0.

decnet congestion-threshold number
no decnet congestion-threshold

Syntax Description

Default

1 packet

Command Mode

Interface configuration

Usage Guidelines

If a router configured for DECnet experiences congestion, it sets the congestion-experienced bit.

Example

The following example sets the congestion threshold to 10:

decnet conversion

To allow Phase IV routers (running Software Release 9.1 or higher) to run in a Phase V network and vice versa, enable conversion with the decnet conversion global configuration command. To disable conversion, use the no form of this command.

decnet conversion nsap-prefix
no decnet conversion nsap-prefix

Syntax Description

Default

Disabled

Command Mode

Global configuration

Usage Guidelines

To enable DECnet conversion, you must configure both DECnet and ISO CLNS on your router.

DECnet Phase V is OSI-compatible and conforms to the ISO 8473 (CLNP/CLNS) and
ISO 9542 (ES-IS) standards. Digital has defined algorithms for mapping a subset of the Phase V address space onto the Phase IV address space and for converting Phase IV and Phase V packets back and forth. This allows a network administrator to support both Phase IV hosts in Phase V networks and Phase V hosts in Phase IV networks.

Our implementation differs from Digital's in how reachability information is advertised. Our implementation allows you to add Phase V support without modifying your existing Phase IV support. It also delays converting packets from Phase IV to Phase V, while Digital's implementation converts as soon as possible.

It is essential that the area you specify in the decnet routing global configuration command is the same as the local area you specified with the net router configuration command for the CLNS network.

Make sure that the area you specify in the decnet conversion command is the same as the area you specified for the CLNS network. Also note that the DECnet area is specified in decimal, and the CLNS area is specified in hexadecimal.

The decnet routing command is specified with a decimal address, while the net command address is specified in hexadecimal. In addition, the nsap-prefix specified on the decnet conversion command must match one of the NETs for this router.

The following guidelines apply:

Example

The following example enables DECnet conversion on a router with the area tag xy and Phase IV address 20.401 using an ISO IGRP router:

Related Commands

A dagger () indicates that the command is documented in another chapter.

net
show decnet interface
show decnet route

decnet cost

To set a cost value for an interface, use the decnet cost interface configuration command. Use the no form of this command to disable DECnet routing for an interface.

decnet cost cost-value
no decnet cost

Syntax Description

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

After DECnet routing has been enabled, you must assign a cost to each interface over which you want DECnet to run. Assigning a cost in effect enables DECnet routing for an interface. Most DECnet installations have an individualized routing strategy for using costs. Therefore, check the routing strategy used at your installation to ensure that costs you specify are consistent with those set for other hosts on the network.

Example

The following example establishes a DECnet routing process for the router and sets the router's DECnet address to 21.456, then sets a cost of 4 for the Ethernet 0 interface:

Related Commands

decnet encapsulation
decnet node-type
decnet routing
show decnet interface
show decnet route

decnet encapsulation

To provide DECnet encapsulation over Token Ring, use the decnet encapsulation interface configuration command.

decnet encapsulation {pre-dec | dec}

Syntax Description

Default

Encapsulation is compatible with other Digital equipment.

Command Mode

Interface configuration

Usage Guidelines

If you have both Software Release 9.0 and 9.1 routers in the same network, you must use the pre-dec encapsulation type on the 9.1 routers.

Example

The following example sets Cisco-style encapsulation for DECnet routing, which means that Cisco and Digital equipment will not interoperate over Token Ring:

Related Commands

decnet cost
show decnet interface

decnet hello-timer

To change the interval for sending broadcast hello messages, use the decnet hello-timer interface configuration command. To restore the default value, use the no form of this command.

decnet hello-timer seconds
no decnet hello-timer

Syntax Description

Default

15 seconds

Command Mode

Interface configuration

Usage Guidelines

The router broadcasts hello messages on all interfaces with DECnet enabled. Other hosts on the network use the hello messages to identify the hosts with which they can communicate directly. On extremely slow serial lines, you may want to increase the default value to reduce overhead on the line.

Example

The following example increases the hello interval to 2 minutes (120 seconds) on interface serial 1:

Related Command

show decnet interface

decnet host

Use the decnet host global configuration command to associate a name-to-DECnet address mapping, which will show up in the output of various commands. To disable name mapping, use the no form of this command.

decnet host name decnet-address
no decnet host name

Syntax Description

Default

No name is defined.

Command Mode

Global configuration

Usage Guidelines

The assigned name is displayed, where applicable, in show decnet route and show hosts EXEC command output.

The name can also be used with the ping decnet command.

Example

The following example defines name-to-DECnet address mapping:

decnet in-routing-filter

To provide access control to hello messages or routing information received on an interface, use the decnet in-routing-filter interface configuration command. Use the no form of this command to remove access control.

decnet in-routing-filter access-list-number
no decnet in-routing-filter

Syntax Description

Default

No access control is defined.

Command Mode

Interface configuration

Example

In the following example, interface Ethernet 0 is set up with a DECnet in-routing filter of 321, which means that any hello messages sent from addresses that are denied in list 321 will be ignored. Additionally, all node addresses listed in received routing messages on this interface will be checked against the access list, and only routes passing the filter will be considered usable.

Related Commands

access-list (standard)
decnet out-routing-filter
show decnet interface

decnet map

To establish an address translation for selected nodes, use the decnet map global configuration command.

decnet first-network map virtual-address second-network real-address

Syntax Description

Default

No address translation is defined.

Command Mode

Global configuration

Usage Guidelines

Keep the following limitations in mind when configuring the Address Translation Gateway (ATG):

As an additional feature and security caution, DECnet "Poor Man's Routing" can be used between nodes outside of the translation map as long as those nodes have access to nodes that are in the map, so that a user on node B could issue the following VMS command:

When a Poor Man's Routing connection is made between two networks, only the two adjacent nodes between the networks will have any direct knowledge about the other network. Application-level network access may then be specified to route through the connection.

Example

In the following example, packets in Network 0 sent to address 19.5 will be routed to Network 1, and the destination address will be translated to 50.1. Packets sent to address 47.1 in Network 1 will be routed to Network 0 as 19.1.

Related Command

show decnet map

decnet max-address

To configure the router with a maximum number of node addresses, use the decnet max-address global configuration command.

decnet [network-number] max-address value

Syntax Description

Default

1023 node addresses

Command Mode

Global configuration

Usage Guidelines

DECnet routers do not have the concept of aging out a route. Therefore, all possible areas or nodes must be advertised as unreachable if they cannot be reached. Since it is best to keep routing updates small, you need to indicate the default maximum possible node and area numbers that can exist in the network.

Example

The following example configures a small network to a maximum address value of 300:

Related Command

decnet max-area

decnet max-area

To set the largest number of areas that the router can handle in its routing table, use the decnet max-area global configuration command.

decnet [network-number] max-area area-number

Syntax Description

Default

63 areas

Command Mode

Global configuration

Example

In the following example, the largest area to be stored in the routing table is 45:

Related Commands

decnet max-address
show decnet interface

decnet max-cost

To set the maximum cost specification for intra-area routing, use the decnet max-cost global configuration command.

decnet [network-number] max-cost cost

Syntax

Description

Default

1022

Command Mode

Global configuration

Usage Guidelines

The router ignores routes within its local area that have a cost greater than the value you specify.

Example

In the following example, the node type is specified as a Level 1 router and the maximum cost is set to 335. Any route whose cost exceeds 335 will be considered unreachable by this router.

Related Commands

decnet max-hops
decnet max-paths
decnet node-type routing-iv
decnet path-split-mode
show decnet interface

decnet max-hops

To set the maximum hop count specification value for intra-area routing, use the decnet max-hops global configuration command.

decnet [network-number] max-hops hop-count

Syntax

Description

Default

30 hops

Command Mode

Global configuration

Example

The following example sets the router to be a Level 1 router, then sets a maximum hop count of 2:

Related Commands

decnet max-cost
decnet max-paths
decnet multicast-map
decnet node-type routing-iv

decnet max-paths

To define the maximum number of equal-cost paths to a destination that the router will keep in its routing table, use the decnet max-paths global configuration command.

decnet [network-number] max-paths value

Syntax Description

Default

1 equal-cost path

Command Mode

Global configuration

Usage Guidelines

Limiting the number of equal-cost paths can save memory on routers with limited memory or very large configurations. Additionally, in networks with a large number of multiple paths and end-systems with limited ability to cache out-of-sequence packets, performance may suffer when traffic is split between many paths.

Limiting the size of the routing table will not affect your router's ability to recover from network failures transparently, provided that you do not make the maximum number of paths too small. If more than the specified number of equal-cost paths exist, and one of those paths suddenly becomes unusable, the router will discover an additional path from the paths it has been ignoring.

Example

In the following example, the router will save no more than three equal-cost paths:

Related Commands

decnet max-cost
decnet max-hops
decnet path-split-mode
show decnet interface
show decnet route

decnet max-visits

To set the limit on the number of times a packet can pass through a router, use the decnet max-visits global configuration command.

decnet [network-number] max-visits value

Syntax Description

Default

63 times

Command Mode

Global configuration

Example

The following example of intra-area routing configuration specifies Level 1 routing, a maximum hop count of 28, and maximum number of visits of 62 (which is more than twice 28).

Related Commands

decnet max-hops
show decnet interface
show decnet traffic

decnet multicast-map

Use the decnet multicast-map interface configuration command to specify a mapping between DECnet multicast addresses and Token Ring functional addresses, other than the default mapping. The no form of this command deletes the specified information.

decnet multicast-map multicast-address-type functional-address
no decnet multicast-map multicast-address-type functional-address

Syntax Description

Default

Enabled, with the default mapping listed in Table 16-2.

Command Mode

Interface configuration

Usage Guidelines

This command is valid for Token Ring interfaces only. The command will reject a functional address that does not start with "C000" or "c000."

Routing multicasts and end node multicasts must be on different functional addresses.

Table 16-2   Default Mapping of DECnet Multicast Address Types and Token Ring Functional Addresses

Example

In the following example, interface Token Ring 1 is configured for multicasts of all Phase IV end nodes and the multicast ID is configured to map to MAC address c000.2222.3333.

decnet node-type

To specify the node type, use the decnet node-type global configuration command.

decnet [network-number] node-type {area | routing-iv}

Syntax Description