Using the AppleTalk Protocol

This document describes the Nx Networks implementation of the AppleTalk" protocol. It includes the following sections:

AppleTalk Overview

At the basic level of the AppleTalk network, connected devices are known as nodes. Nodes can be personal computers, file servers, print servers, and routers. At the next level are networks. A network is a group of nodes connected to a single logical cable. Groups of networks connected by routers or bridges comprise an internet. User-defined groups of nodes from one or more networks within an internet are zones.

The Nx Networks implementation of AppleTalk supports Ethernet, Token Ring, and FDDI LAN connections and PPP, Frame Relay, and ISDN WAN connections. Figure 5 shows a sample of an AppleTalk internet.

Figure 5 Sample AppleTalk Internet

AppleTalk Addressing

AppleTalk nodes use a 24-bit internet address. A 16-bit network number and an 8-bit node number (node ID). The node ID is an 8-bit number that, when combined with the AppleTalk network number of a node, uniquely identifies each node on a network. Values 0, 254, and 255 are invalid.

Network Range

You can assign more than one network number to an AppleTalk network by assigning a network range. The network range is set of consecutive network numbers. Each network within the AppleTalk internet is assigned a unique, non-overlapping network range. This allows you to have more than 253 devices on one network. Each network can have (253 x network range) nodes.

Dynamic Addressing

AppleTalk uses dynamic addressing. With this process, AppleTalk hosts on the network negotiate a device's node number. A node first tries the node number that was its most recent address. If that value is not available, the node then searches for the next available address. If it reaches 254 without finding an available node number, it tries the next network number in the range.

Seed Routers

With dynamic addressing, you do not need to specify all fields of an AppleTalk address to configure a router. If a preconfigured AppleTalk router, known as seed router, is on the network, it supplies network numbers for new routers. The seed router sends out the address information to all other routers on its connected network. The seed router must come up first and verify the configuration of the other routers. If the configuration is valid, the other routers start functioning. Routers that are not seed routers must first communicate with a seed router before they can function.

As long as one seed router exists on each the network, you do not need to configure the other interfaces and routers connected to that cable because they obtain their routing information from the seed. There are usually several seed routers on a network in case one of them fails. Also, a router can be a seed router for some or all of its network interfaces.

Nonseed Routers

A nonseed router cannot begin routing until the router determines its network number. If you set the network number to zero, the interface does not send any packets until it receives a valid network number. Upon receiving a Routing Table Maintenance Protocol (RTMP) update, the router is informed of the network number for the interface receiving the packet with the update. Every table update contains the network number of the network on which the packet was sent. Through this exchange, the router determines the network number of the receiving interface.

The AppleTalk Protocol Stack

Figure 6 shows the AppleTalk protocols that this implementation supports along with the corresponding Open Systems Interconnection (OSI) protocol layers.

Figure 6 AppleTalk Protocol Stack and
Corresponding OSI Protocol Layer

These protocols are described in the next sections.

TLAP and ELAP

This implementation supports TLAP and ELAP at the data link layer to transmit AppleTalk packets on Token Ring and Ethernet networks. LocalTalk Link Access Protocol (LLAP) is not supported.

AARP

Each node on the network must have a unique hardware address, for example, a 48-bit Ethernet node address.

Ethernet node addresses are derived from the hardware address or from a user-defined initial address. When an Ethernet AppleTalk node dynamically assigns a node address, the AARP probe confirms that the address is unique. If the address is not unique, it selects a new address. AARP maintains a set of AppleTalk protocol-to-hardware address mappings for the AppleTalk protocol. AARP stores and updates these address mappings in an address mapping table.

DDP

This network layer protocol is responsible for forwarding AppleTalk packets from a source node to a destination node.

RTMP

RTMP specifies how AppleTalk maintains the routing table for the entire internet.

Every 10 seconds RTMP transmits packets with good and suspect entries to routing tables in connected routers. The routers receive these packets and update the corresponding entries to good or suspect. Every 20 seconds RTMP also updates the age of each entry in the routing table. Entries with a state of good become suspect and entries with a state of suspect become bad. After an entry has been bad for 20 seconds, RTMP deletes the entry.

RTMP updates and maintains routing table hop counts, and it deletes all entries with a hop count of 16 or greater.

Hosts can send RTMP request packets to a router on an internet to learn the local network number. The router responds with an RTMP response packet.

NBP

AppleTalk uses entity names to specify the function, attributes, and location of an entity in a network. The Name Binding Protocol maps these human- readable names to machine-readable addresses.

An entity name is an 8-bit ASCII character string that has three fields: object, type, and zone. Each of these fields is a string of not more than 32 characters.

Object is the type of service offered by the entity, such as printing, file sharing, or mail service.
Type specifies the attributes of the entity, such as a laser printer.
Zone identifies the location of the entity.

EP

The Echo Protocol tests whether or not a destination is reachable by sending an Echo Request packet to a node on the internet. If the packet reaches the node, the node responds with an Echo Response packet.

ZIP

ZIP allows routers to learn zone names. It keeps a list of zone names and associated network numbers in the Zone Information Table (ZIT).

ZIP requires routers to transmit ZIP queries every ten seconds for each network in the routing table that does not have a zone name. If the receiving router knows the zone name and network number mapping, it responds with a ZIP Reply packet. Using this query-reply method, eventually all the routers will have identical information in their ZITs. Hosts obtain ZIT data by sending and receiving ATP packets to and from the router.

Features Supported

This section describes the following features supported in this implementation of AppleTalk:

Filtering zone names and network numbers
Split-horizon routing
Half routers

Filtering Zone Names and Network Numbers

Zone name filtering and network number filtering increases security and makes it easier to administrate the internet.

Zone name filtering restricts access to zones by filtering the zones that are visible to clients. This feature enhances security, and, since users are presented with a limited number of zones from which to choose, it increases usability.

While zone name filtering lets you partially filter a network, network number filtering lets you completely filter a network. This further increases security and makes administrating the internet easier.

See Setting Up Zone Filters and Setting Up Network Filters for information on how to configure zone and network number filters.

Split-horizon Routing

The RTMP broadcasts routing information every 10 seconds. In large internetworks where many routers are connected to a backbone, RTMP packets can take up a significant portion of available bandwidth. Split-horizon routing, which is enabled as a default on the router, reduces the size of RTMP packets. To do so, it does not send routing information out of the same port in which it was received. It removes these entries from the RTMP packet.

However, in a partially-meshed Frame Relay network, as shown in Figure 7, the routers at the branches cannot communicate with each other unless the router at headquarters broadcasts all routing information to all other routers. In this case, you need to disable split-horizon on the Frame Relay interface at headquarters. You should leave split-horizon enabled at each of the branches to keep them from generating unnecessary traffic.

Figure 7 Partially-Meshed Frame Relay Network

In partially-meshed Frame Relay networks, you should configure addresses for the AppleTalk interfaces. This prevents the AppleTalk protocol from attempting to dynamically learn addresses, which can fail on partially-meshed Frame Relay networks.

Half Routers

When you connect an interface to a serial line, you can set up the interface as a half router. In half-router mode, the serial line connection is invisible to other routers, but it still transmits AppleTalk routing information and data packets. If you have a half router at one end of a serial line, you must configure the router interface at the other end of the serial line as a half router. This feature makes the router interoperable with other vendor's half routers.

Figure 8 Sample Half Router Configuration

To set up a router interface as a half router, set the network number and node number to zero (0), which are the default settings. Do not assign a zone name to the interface.

Configuration Procedures

This section describes how to configure AP2. The tasks you need to perform are

Enabling AP2
Setting network parameters

Optional tasks are

Setting up zone filters
Setting up network filters
Disabling checksumming

For the configuration changes to take effect, you must restart the router.

To access the AP2 configuration prompt enter protocol ap2 at the Config> prompt.

Config>protocol ap2
AP2 protocol user configuration
AP2 config>

Enabling AP2

If you have multiple routers transferring AP2 packets, specify these parameters for each router.

1. Globally enable AP2 on the router.

AP2 config>enable ap2

2. Enable the specific interfaces over which AP2 is to send packets.

AP2 config>enable interface 1

Setting Network Parameters

To set up your router as a seed router, set the network range, a starting node number, and at least one zone name. You can configure some interfaces on a router as seed routers and leave other interfaces as nonseed routers. You must have at least one seed router for each AppleTalk network, and you should configure several seed routers on a network in case one of them fails.

Note: Do not set a network range or a node number for half routers. See Half Routers for more information.

1. Set the Network Range.

AP2 config>set net-range
Interface #  [0]? 1
First Network range number (1-65279, or 0 to delete) []? 1
Last Network range number (1-165279) []? 5

Enter the same first and last values for a single numbered network.

2. Set the starting node number for the interface. The router AARP probes for this node. If the number is already in use, the router chooses a new number.

AP2 config>set node-number
Interface #  [0]? 1
Node number (decimal) []? 23

3. Add one or more zone names for the network attached to the interface. If you define a network range for an interface, you should also define the zone names for the interface. If you did not define a network number, do not define zone names.

AP2 config>add zone
Interface # [0]? 1
Zone name []? Finance

To view your configuration, enter list at the AP2 config> prompt.

Setting Up Zone Filters

Zone filtering lets you filter zones in each direction on each interface. To filter incoming packets, set up an input filter. To filter outgoing packets, set up an output filter. The interface does not re-advertise filtered zone information in the direction that you define. To set up a zone filter:

1. Add zone filters to an interface.

To add an input zone filter, use the add zfilter in command.
To add an output zone filter, use the add zfilter out command.

The software prompts you for the interface number and the name of the zone that you want to filter.

AP2 config>add zfilter in
Interface # [0]? 1
Zone name []? Admin

2. Enable the zone filters that you added.

To enable an input zone filter, enter enable zfilter in.
To enable an output zone filter, enter enable zfilter out.

The software prompts you for the interface number and for whether or not the filter is inclusive or exclusive. Inclusive filters forward only the zone information in a filter. Exclusive filters block only the zone information in a filter.

AP2 config>enable zfilter in
Interface # [0]? 1
INCLUSIVE/EXCLUSIVE [INCLUSIVE]? exc

Following are some examples that explain how to set up zone filters in the internet shown in Figure 9.

Figure 9 Sample AppleTalk Internet

Example 1

This example explains how to filter the Manufacturing zone from all other networks. To do so, you would set up an input filter on Interface 1 of Router A to exclude the Manufacturing zone.

1. On Router A, add an input zone filter to Interface 1.

AP2 config>add zfilter in
Interface # [0]? 1
Zone name []? Manufacturing

2. Enable the input zone filter and make the filter exclusive.

AP2 config>enable zfilter in
Interface # [0]? 1
INCLUSIVE/EXCLUSIVE [INCLUSIVE]? exc

Manufacturing zone information is now excluded from entering Router A, thereby filtering the zone from the rest of the internet.

Example 2

This example shows how to filter the Manufacturing zone from Network 11-15, but still allow the Manufacturing zone to be visible on Network 1-5. To do so, you would set up an output filter on Interface 3 of Router A to exclude Manufacturing zone information from being forwarded out of Interface 3. The interface will continue to advertise Manufacturing zone information over interfaces 0 and 1 on Router A, making it visible on Network 1-5.

1. Add an output zone filter to Interface 3.

AP2 config>add zfilter out
Interface # [0]? 3
Zone name []? Manufacturing

2. Enable the output zone filter and make the filter exclusive.

AP2 config>enable zfilter out
Interface # [0]? 3
INCLUSIVE/EXCLUSIVE [INCLUSIVE]? exc

This filter excludes Manufacturing zone information from the output of Interface 3.

Example 3

This example shows how to set up a filter so that the Admin zone is visible on all networks, but the Finance zone is not visible to the rest of the internet.

1. Add an input zone filter to Interface 0 on Router A.

AP2 config>add zfilter in
Interface # [0]? 0
Zone name []? Admin

2. Enable the input zone filter and make it inclusive.

AP2 config>enable zfilter in
Interface # [0]? 0
INCLUSIVE/EXCLUSIVE [INCLUSIVE]? inc

By setting up this input filter as inclusive, interface 0 forwards only Admin zone information to the rest of the internet.

Setting Up Network Filters

Network filters are similar to zone filters, except they let you filter an entire network. To set up a network filter, follow these steps:

1. Add a network filter. Use add nfilter in to add an input network filter to an interface. Use add nfilter out to add an output network filter to an interface. For example:

AP2 config>add nfilter out
Interface # [0]? 0
First Network range number (decimal)[0]? 11
Last Network range number (decimal) [0]? 15

The network range you enter here must match the range that you assigned to that network.

2. Enable the network filter that you added and make it either inclusive or exclusive. Inclusive filters forward only network information in a filter. Exclusive filters block only network information in a filter, and they allow all other network information to be forwarded.

AP2 config>enable nfilter in
Interface # [0]? 0
INCLUSIVE/EXCLUSIVE [INCLUSIVE]? exc

Example

This example shows how to filter Network 6-10 so that it is not visible to Network 16-20 in the internet shown in Figure 10.

Figure 10 Sample AppleTalk Internet

1. Add an output network filter for Network 6-10 to Interface 2 on Router B.

AP2 config>add nfilter out
Interface # [0]? 2
First Network range number (decimal) [0]? 6
Last Network range number (decimal) [0]? 10

2. Enable the output network filter as exclusive.

AP2 config>enable nfilter out
Interface # [0]? 0
INCLUSIVE/EXCLUSIVE [INCLUSIVE]? exc

This filter excludes all information on Network 6-10 from being forwarded through Interface 2 to Network 16-20.

Enabling Checksumming

As the default, the router does not compute DDP checksums of packets it originates. To enable checksumming, use the enable checksum command.

AppleTalk Commands

Table 10 summarizes and the next sections explain the AppleTalk commands.

Press Space twice after you type a command to display the available options for each command.

[C] means the command is available at the AP2 config> prompt.

[M] means the command is available at the AP2> prompt. To display the AP2> prompt, enter protocol ap2 at the Monitor> prompt.

Table 10 AppleTalk Commands

Command Function

Add [C] Adds zone names, network filters, and zone filters to an interface.

Cache [M] Displays the cache table entries.

Clear-Counters [M] Clears all cache usage counters and packet overflow counters.

Counters [M] Displays the overflow count of AppleTalk packets for each interface.

Delete [C] Deletes the zone names, interfaces, network filters, and zone filters.

Disable [C] Disables interfaces, checksumming, split-horizon routing, network filters, zone filters, or globally disables AP2.

Dump [M] Displays the current state of the routing table for all networks in the internet and their associated zone names.

Enable [C] Enables interfaces, checksumming, split-horizon routing, network filters, zone filters, or globally enables AppleTalk.

Exit [C] [M] Returns to the previous prompt.

Interface [M] Displays the current addresses of the interfaces.

List [C] Displays the current AppleTalk configuration.

Set [C] Sets the cache size, network range, and node number.

Table 10 AppleTalk Commands
Command	Function
Add [C]	Adds zone names, network filters, and zone filters to an interface.
Cache [M]	Displays the cache table entries.
Clear-Counters [M]	Clears all cache usage counters and packet overflow counters.
Counters [M]	Displays the overflow count of AppleTalk packets for each interface.
Delete [C]	Deletes the zone names, interfaces, network filters, and zone filters.
Disable [C]	Disables interfaces, checksumming, split-horizon routing, network filters, zone filters, or globally disables AP2.
Dump [M]	Displays the current state of the routing table for all networks in the internet and their associated zone names.
Enable [C]	Enables interfaces, checksumming, split-horizon routing, network filters, zone filters, or globally enables AppleTalk.
Exit [C] [M]	Returns to the previous prompt.
Interface [M]	Displays the current addresses of the interfaces.
List [C]	Displays the current AppleTalk configuration.
Set [C]	Sets the cache size, network range, and node number.

Add [C]

Adds a zone name to an interface, adds a zone name as the default for the interface, or adds network and zone filters.

Syntax: add

zone
defaultzone
nfilter in
nfilter out
zfilter in
zfilter out

zone

You can add one or more zone names for each interface. If you define a network number for an interface, you should also define the zone names for the interface. If you did not define a network number, do not define zone names.

Example: add zone

Interface # [0]? 0
Zone name []? Finance

defaultzone

Adds a default zone name for the interface. If a node on the network requests a zone name that is invalid, the router assigns the default zone name to the node until another zone name is chosen.

If you add more than one default to an interface, the last one added overrides the previous default. If you do not add a default, the first zone name added using the zone command is the default.

Example: add defaultzone

Interface # [0]? 0
Zone name []? Headquarters

nfilter in

Adds a network filter to the input of the interface. The network range that you enter must match the network range you set for that interface. You cannot filter only a portion of a network range. For example, if you set a network range of 1-10, and you set up a filter for 5-8, the router filters the full network range of 1-10.

Example: add nfilter in

Interface # [0]? 0
First Network range number (decimal) [0]? 1
Last Network range number (decimal) [0]? 10

nfilter out

Adds a network filter to the output of the interface. The network range that you enter must match the network range you set for that interface. You cannot filter only a portion of a network range. For example, if you set a network range of 1-10, and you set up a filter for 5-8, the router filters the full network range of 1-10.

Example: add nfilter out

Interface # [0]? 0
First Network range number (decimal) [0]? 11
Last Network range number (decimal) [0]? 20

zfilter in

Adds a zone name filter to the input of the interface.

Example: add zfilter in

Interface # [0]? 1
Zone name []? Marketing

zfilter out

Adds a zone name filter to the output of the interface.

Example: add zfilter out

Interface # [0]? 0
Zone name []? Corporate

Cache [M]

Displays information about the cache-size entries.

Syntax: cache

Example: cache

Destination  Net Number Usage  Next Hop
122/2        2    1         127/5
138/5        1    0         127/5
 23/7        1    1         Direct


Destination	AppleTalk node address (network number/node number).
Net	Number of the interface used to forward to the destination node.
Usage	Number of times this cache entry has been used.
Next Hop	The AppleTalk address of the next hop router used to forward a packet to the destination node, or Direct if the destination node is directly connected to the interface.

Clear-Counters [M]

Clears all cache usage counters and packet overflow counters that you display using the cache command and counters command.

Syntax: clear-counters

Example: clear-counters

Counters [M]

Displays the number of packet overflows on each network interface that sends and receives AppleTalk packets. Counters also displays the number of times the AppleTalk forwarder input queue was full when the interface received packets.

Syntax: counters

Example: counters

APL2 Input Packet Overflows

     Net        Count
    FR/0        0
    Eth/1        4
    PPP/2        22
    TKR/3        0

Delete [C]

Deletes zone names, network or zone name filters, or deletes all AppleTalk information from an interface.

Syntax: delete

zone
nfilter in
nfilter out
zfilter in
zfilter out
interface

zone

Deletes a zone name from the interface zone list.

Example: delete zone

Interface # [0]? 2
Zone name []? corporate

nfilter in

Deletes a network filter from the input of the interface. Enter the same network range you set using the add nfilter in command.

Example: delete nfilter in

Interface # [0]? 0
First Network range number (decimal) [0]? 1
Last Network range number (decimal) [0]? 12

nfilter out

Deletes a network filter from the output of the interface. Enter the same network range you set using the add nfilter out command.

Example: delete nfilter out

Interface # [0]? 0
First Network range number (decimal) [0]? 11
Last Network range number (decimal) [0]? 20

zfilter in

Deletes a zone name filter from the input of the interface.

Example: delete zfilter in

Interface # [0]? 1
Zone name []? Marketing

zfilter out

Deletes a zone name filter from the output of the interface.

Example: delete zfilter out

Interface # [0]? 1
Zone name []? Marketing

interface

Deletes all AP2 information for the specified interface. Sometimes this is the only way to delete zone names that have non-printing characters.

Disable [C]

Disables AP2 on all interfaces or on a specified interface, disables checksumming, filtering, or split horizon routing.

Syntax: disable

ap2
checksum
interface
nfilter in
nfilter out
zfilter in
zfilter out
split-horizon-routing

ap2

Disables AP2 on all interfaces.

Example: disable ap2

checksum

Specifies that the router does not compute the checksum in packets it generates.

Example: disable checksum

interface

Disables AppleTalk on the specified interface.

Example: disable interface

Interface #  [0]? 2

nfilter in

Disables, but does not delete, the input network filters on this interface.

Example: disable nfilter in

Interface # [0]? 2

nfilter out

Disables, but does not delete, the output network filters on this interface.

Example: disable nfilter out

Interface # [0]? 2

zfilter in

Disables, but does not delete, the input zone filters on this interface.

Example: disable zfilter in

Interface # [0]? 1

zfilter out

Disables, but does not delete, the output zone filters on this interface.

Example: disable zfilter out

Interface # [0]? 1

split-horizon-routing

Disables split-horizon routing on this interface. You need to disable split-horizon routing only on Frame Relay interfaces that are on a hub in a partially-meshed Frame Relay network. Disabling split-horizon routing causes all of the routing tables to be propagated on this interface. See Split-horizon Routing for more information.

Example: disable split-horizon-routing

Interface #  [0]? 1

Dump [M]

Displays routing table information about the interfaces on the router that forward AppleTalk packets.

Syntax: dump

Example: dump

Dest Net  Cost  Stat   Next hop  Source  Zone
  10-19   0     Dir    0/0               "Ethertalk", "Sales"
  40-49   1     Good   10/13             "Marketing",
                                        "CustomrSer","TokenTalk"
  20-29   2     Sspct  10/13            "Fuchsia", "Backbone",
                                "Engineering","MKTING"

You can also use the dump command with a specific interface to display the routes that are visible on that interface. You can use this feature to make sure filters are configured correctly because it shows whether or not filtered zones or networks are visible to an interface.

Example: dump 0

View for interface 0

Dest net   Cost  State   Next hop   Zone
  214-214   1     Good     152/152  "fddi-214"
  153-153   0      Dir              "eth153"
  152-152   0      Dir              "ser152"

3 entries


Dest Net	Destination network number, in decimal.
Cost	Number of router hops to this destination network.
State	State of the entry in the routing table. It includes the following:
	Dir— The routing table is directly connected to the destination network, the interface is enabled, and the network number is known. Good— An RTMP packet containing a good tuple for this network was heard in the last 20 seconds.
	Suspct— No RTMP tuple was received for this network in the last 20 seconds. Bad— No RTMP tuple was received for this network in the last 40 seconds. RTMP packets with tuples listing this network as unreachable will be sent for 20 seconds, then the network will be deleted from the RTMP routing table.
Next hop	The next hop for packets going to networks that are not directly connected. For directly-connected networks, this is node number 0.
Source	This column appears only if you have enabled Phase 1/Phase 2 translation. It lists the originating network type for the table entry. If this is the case, the occurrence of multiple zones per entry are not displayed because only one zone per network can be configured for communication between Phase 1 and 2 networks.
Zone(s)	Specifies the name for the network. The zone name(s) is enclosed in double quotes in case there are embedded spaces or non-printing characters. If the zone name contains characters beyond the 7-bit ASCII character set (they are 8-bit), the zone name that displays depends on the characteristics of your terminal.

Enable [C]

Globally enables AP2 on the router or on a specified interface, enables checksumming, network or zone filters, and split-horizon routing.

Syntax: enable

ap2
checksum
interface
nfilter in
nfilter out
zfilter in
zfilter out
split-horizon-routing

ap2

Enables the AppleTalk Phase 2 packet forwarder over all of the interfaces on this router.

Example: enable ap2

checksum

Causes the router to checksum all AP2 packets it forwards.

Example: enable checksum

interface

Enables the router to send AppleTalk Phase 2 packets over specific interfaces.

Example: enable interface

Interface #  [0]? 1

nfilter in

Enables network input filters and controls how the filter is applied to the interface. Inclusive forwards matches. Exclusive drops matches.

Example: enable nfilter in

Interface # [0]? 1
INCLUSIVE/EXCLUSIVE [INCLUSIVE]? inc

nfilter out

Enables network input filters and controls how the filter is applied to the interface. Inclusive forwards matches. Exclusive drops matches.

Example: enable nfilter in

Interface # [0]? 1
INCLUSIVE/EXCLUSIVE [INCLUSIVE]? exc

zfilter in

Enables and controls how the zone input filter is applied to the interface. Inclusive forwards matches. Exclusive drops matches.

Example: enable zfilter in

Interface # [0]? 0
INCLUSIVE/EXCLUSIVE [INCLUSIVE]? inc

zfilter out

Enables and controls how the zone output filter is applied to the interface. Inclusive forwards matches. Exclusive drops matches.

Example: enable zfilter out

Interface # [0]? 0
INCLUSIVE/EXCLUSIVE [INCLUSIVE]? inc

split-horizon-routing

Enables split-horizon routing on the interface. The default is enabled.

Example: enable split-horizon-routing

Interface #  [0]? 1

Exit [C] [M]

Returns to the previous prompt.

Syntax: exit

Example: exit

Interface [M]

Displays the addresses of all interfaces in the router on which AP2 is enabled. If the interface is disabled, this command shows that status.

Syntax: interface

Example: interface

Interface    Addresses
  PPP/0      0/1 on net 1000-1000  default zone "SerialLine"
  Eth/0      10/52 on net 10-19    default zone "Sales"
  SL/1       0/0 in startup range
  TKR/0      0/0 on net 20-29 default zone "Backbone"

You can also enter interface followed by a specific interface number to view the AP2 configuration of that interface.

Example: interface 1

Eth/0   1/30 on net 1-5   default zone "marketing" 

Input Net filters inclusive   1-5
Output Zone filters inclusive "finance"
Output Net filters exclusive  1-5

List [C]

Displays the current AppleTalk configuration. In the example, the router is a seed router on interfaces 0 and 1, and an unseeded router on interface 2. Interface 2 learns the network number and zone name from a seed router.

Syntax: list

Example: list

APL2 globally      enabled
Checksumming       disabled
Cache size         500

List of configured interfaces:

Interface       netrange/  node           Zone

0               1000-1000/  1            "SerialLine" (Def)
 Input ZFilters disabled       
 Input NFilters (inclusive)    
 Output ZFilters disabled      
 Output NFilters disabled    
 Split-horizon-routing enabled
1               10-19/  52               "EtherTalk","Sales"(Def)
 Input ZFilters disabled       
 Input NFilters (inclusive)    
 Output ZFilters disabled      
 Output NFilters disabled    
 Split-horizon-routing enabled
2               unseeded net/  0
 Input ZFilters disabled       
 Input NFilters (inclusive)    
 Output ZFilters disabled      
 Output NFilters disabled     
 Split-horizon-routing disabled


APL2 globally	Indicates whether AP2 is globally enabled or disabled.
Checksumming	Indicates whether checksumming is enabled or disabled.
Cache size	Number of fastpath cache entries.
List of configured interfaces	Lists each interface number and its network range, node number, and zone name(s) as well as the default zone. For each interface also lists whether or not input and output zone filters and network filters and enabled or disabled. If they are enabled, indicates whether or not they are inclusive or exclusive.
Split-horizon-routing	Shows whether or not split-horizon is enabled or disabled on each interface.

Set [C]

Defines the cache-size of fastpath, the network range of seed routers, and the node number.

Syntax: set

cache-size
net-range
node-number

cache-size

Cache-size corresponds to the number of AppleTalk nodes that can simultaneously communicate through this router using the fastpath feature. (Fastpath is a method of pre-calculating MAC headers to forward packets more quickly.) The default is 500, which allows up to 500 nodes to simultaneously communicate through the router and still use fastpath. If the number of nodes becomes greater than the cache size, the router still forwards the packets, but it does not use fastpath.

You can set cache size from 100 to 10,000. You need to change this default only for very large networks. Although not recommended, setting the cache-size to zero disables the fastpath feature and no memory is used for the cache. Each cache-size entry uses 36 bytes of memory.

Example: set cache-size

number of cache entries (100-10000), or 0 to disable [500]? 700

net-range

Assigns a network range to the interface. The first number is the lowest number of the network range, and the last number is the highest number of the network range. Legal values are 1 to 65279.

Enter the same first and last values for a single numbered network. To delete the network range for the interface and turn the seeded router into an unseeded router, enter zero for the first and last numbers.

Example: set net-range

Interface #  [0]? 1
First Network range number(1-65279, or 0 to delete)[0]? 1
Last Network range number (1-65279) [0]? 15

Note: If you define a network number for an interface, use the add zone command to define the zone names for the interface.

node-number

Assigns the starting node number for the router. Legal values are 1 to 253. Zero deletes the node number for the interface and forces the router to choose a number at random. The router AARP probes for this node, and if it is already in use, chooses a new node.

Example: set node-number

Interface #  [0]? 2
Node number (1-253, or 0 to delete) []? 45

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