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Configuring ILMI

Configuring ILMI

This chapter describes the Integrated Local Management Interface (ILMI) protocol implementation for Cisco DSLAMs with NI-2 cards, and includes the sections:

ILMI Overview

The DSLAM uses ILMI to automatically identify which of its interfaces are User-Network Interface (UNI), attached to ATM end systems, and which are Network-to-Network Interface (NNI), attached to other systems. It can also differentiate between private and public network links. This information is used by the ATM routing protocols, Private Network-to-Network Interface (PNNI), and Interim-Interswitch Signaling Protocol (IISP) to automatically discover and gain access to a network of interconnected DSLAMs.

The ILMI protocol is also used for ATM address registration across an ATM UNI, and for

ILMI reduces the need for manual configuration of attached end systems and is important in the operation of DSLAM-based networks.

Configuring the Global ILMI System

This section describes configuring the ATM address and displaying the ILMI configuration for the entire DSLAM.

Configuring the ATM Address

The DSLAM is autoconfigured with an ATM address using a hierarchical addressing model similar to the Open System Interconnection (OSI) network service access point (NSAP) addresses. PNNI uses this hierarchy to construct ATM peer groups. ILMI uses the first 13 bytes of this address as the switch prefix that it registers with end systems.

During the initial startup, the DSLAM generates an ATM address using the defaults described in "Initially Configuring the Cisco DSLAM."

Note   The most important rule in the addressing scheme is to maintain the uniqueness of the address across very large networks.

To configure a new ATM address that replaces the previous ATM address and generates a new PNNI node ID and peer group ID, see "Configuring ATM Routing and PNNI."

You can configure multiple addresses for a single DSLAM, and use this configuration during ATM address migration. ILMI registers end systems with multiple prefixes during this period until an old address is removed. PNNI automatically summarizes all of the switch's (or DSLAM's) prefixes in its reachable address advertisement.

To configure a new ATM address that replaces the previous ATM address when you are running IISP only, perform these tasks in global configuration mode:

Step

Command

Task

    

    	1. 
    



 atm address atm_address


 At the configuration mode prompt, configure the new ATM address for the DSLAM.


    

    	2. 
    



 no atm address atm_address


 At the configuration mode prompt, remove the old ATM address from the DSLAM.

Example

This example shows how to add the ATM address prefix 47.0091.8100.5670.000.0ca7.ce01 using the ellipses (...) to add the default MAC address as the last six bytes, and displays the results.

DSLAM(config)# atm address 47.0091.8100.5670.0000.0ca7.ce01...
Building configuration...
Current configuration:
 
<information deleted>
 
!
atm abr-mode efci
atm lecs-address-default 47.0091.8100.0000.0040.0b0a.1281.0040.0b4e.d023.00 1
atm lecs-address-default 47.0091.8100.0000.0040.0b0a.1281.0040.0b07.4023.00 2
atm ilmi default-access permit matching-prefix
atm address 47.0091.8100.5670.000.0ca7.ce01.2b81.00.7901.00
atm address 47.0091.8100.0000.0060.3e5a.7901.0060.3e5a.7901.00
atm router pnni
 statistics call
 node 1 level 56 lowest

Configuring Global ILMI Access Filters

The ILMI access filter feature allows you to permit or deny certain ILMI registered addresses.

Note   If you want to allow certain addresses to be registered through ILMI, but restrict those addressees from being advertised through PNNI, use the PNNI suppressed summary address feature instead. For additional information, see "Configuring ATM Routing and PNNI."

If end systems are allowed to register arbitrary addresses via ILMI, including addresses that do not match the ILMI prefixes used on the interface, a security hole may be opened. The ILMI access filter feature closes the security hole by permitting or denying ILMI registration of different classes of addresses.

The ILMI access filter allows you to configure two levels of access filters:

In either level, you can choose among these options:

To configure global ILMI access filters, use this global configuration command:

Command

Task

 atm ilmi default-access permit {all | matching-prefix [all-groups | wellknown-groups]}


 Configure an ILMI default access filter.

Example

This example shows how to configure the global default access filter for ILMI address registration to allow well-known group addresses and addresses with matching prefixes and displays the result:

DSLAM(config)# atm ilmi default-access permit matching-prefix wellknown-groups
 
DSLAM# show running-config
Building configuration...
Current configuration:
    <information deleted>
atm abr-mode efci
atm lecs-address-default 47.0091.8100.0000.0040.0b0a.1281.0040.0b4e.d023.00 1
atm lecs-address-default 47.0091.8100.0000.0040.0b0a.1281.0040.0b07.4023.00 2
atm ilmi default-access permit matching-prefix
atm address 47.0091.8100.5670.000.0ca7.ce01.2b81.00.7901.00
atm address 47.0091.8100.0000.0060.3e5a.7901.0060.3e5a.7901.00
atm router pnni
 statistics call
 node 1 level 56 lowest

Displaying the ILMI Global Configuration

To display the DSLAM ILMI configuration, use these EXEC commands:

Command

Task

 show atm address


 Display the ATM addresses.


 show atm ilmi-configuration


 Display the ILMI configuration. 


 show atm ilmi-status


 Display the ILMI status.

Examples

This example shows the ATM address and the LECS address:

ni2-3# show atm addresses
 
Switch Address(es):
  47.009181000000007BF4447801.007BF4447801.00 active
 
Soft VC Address(es):
  47.0091.8100.0000.007b.f444.7801.4000.0c80.0010.00 ATM0/1
  47.0091.8100.0000.007b.f444.7801.4000.0c80.0020.00 ATM0/2
 
ILMI Switch Prefix(es):
  47.0091.8100.0000.007b.f444.7801
 
ILMI Configured Interface Prefix(es):
 
LECS Address(es):

This example shows the ILMI configuration:

DSLAM# show atm ilmi-configuration
 
Switch ATM Address (s) : 
1122334455667788990112233445566778899000           
LECS Address (s):
1122334455667788990011223344556677889900
ARP Server Address (s):
1122334455667788990011223344556677889900

This example shows the ILMI status:

DSLAM# show atm ilmi-status
 
Interface : ATM0/0 Interface Type : Local
Configured Prefix(s) :
47.0091.8100.0000.0003.c386.b301
 
Interface : ATM0/1 Interface Type : Private NNI
ILMI VCC : (0, 16) ILMI Keepalive : Disabled
Configured Prefix(s) :
47.0091.8100.0000.0003.c386.b301
 
Interface : ATM0/2 Interface Type : Private NNI
ILMI VCC : (0, 16) ILMI Keepalive : Disabled
Configured Prefix(s) :
47.0091.8100.0000.0003.c386.b301

Configuring an ILMI Interface

To configure an ILMI interface on a per-interface basis, perform these tasks, beginning in global configuration mode:

Step

Command

Task

    

    	1. 
    



 interface atm slot/port[.vpt#]


 Select interface port.


    

    	2. 
    



 atm auto-configuration


 Enable ILMI auto configuration, including determination of interface protocol, version and side.


    

    	3. 
    



 atm address-registration


 Configure ILMI address registration for a specified interface.


    

    	4. 
    



 auto-link-determination


 Enable ILMI link determination feature.


    

    	5. 
    



 atm ilmi-keepalive [seconds [retry retry_number]]


 Configure ILMI keepalive.

Note   If the ILMI VC (by default VCI = 16) is disabled, then the ILMI is disabled.
Examples

This example shows how to enable ILMI autoconfiguration on ATM interface 0/2:

DSLAM(config)# interface atm 0/2
DSLAM(config-if)# atm-autoconfiguration

This example shows how to enable ATM address registration on ATM interface 0/2:

DSLAM(config)# interface atm 0/2
DSLAM(config-if)# atm address-registration
Note   If you use the no atm address-registration command to disable ILMI on this interface, the keepalives and responses to incoming ILMI queries continue to function. To disable ILMI at this interface, use the no atm ilmi-enable command.

This example shows how to configure the ILMI ATM interface 0/2 with a keepalive time of 20 seconds and retry count of 3 and displays the ILMI interface configuration:

DSLAM(config)# interface atm 0/2
DSLAM(config-if)# atm ilmi-keepalive 20 retry 3
 
DSLAM# show atm ilmi-status atm 0/2
 
Interface : ATM0/2 Interface Type : Private NNI
ILMI VCC : (0, 16) ILMI Keepalive : 20
Configured Prefix(s) :
47.0091.8100.0000.0003.c386.b301

Configuring per-Interface ILMI Address Prefixes

The DSLAM allows configuration of per-interface ILMI address prefixes to allow you to register different address prefixes with end systems attached to different interfaces. When you configure per-interface ILMI address prefixes, they override the prefixes derived from the first 13 bytes of the switch ATM addresses for that specific interface.

You can configure multiple ILMI address prefixes on each interface. For example, during ATM address migration.

To configure a per-interface ILMI address prefix, perform these tasks, beginning in global configuration mode:

Step

Command

Task

    

    	1. 
    



 interface atm slot/port[.vpt#]


 Specify an ATM interface and enter interface configuration mode.


    

    	2. 
    



 atm prefix 13-byte-prefix


 Configure the ILMI address prefix.

Examples

This example shows how to change the ATM address of the DSLAM from the autoconfigured address 47.0091.8100.0000.0041.0b0a.1081.0041.0b0a.1081.00 to the new address 47.0091.8100.5670.0000.0000.1122.0041.0b0a.1081.00:

DSLAM(config)# atm address 47.0091.8100.5670.0000.0000.1122...
DSLAM(config)# no atm address 47.0091.8100.0000.0041.0b0a.1081...

This example shows how to configure an additional ATM addresses manually. The address prefix 47.0091.8100.0000.0003.c386.b301 on ATM interface 0/1 is configured:

DSLAM(config)# interface atm 0/1
DSLAM(config-if)# atm prefix 47.0091.8100.0000.0003.c386.b301

This example uses the show atm address command to display the ILMI address prefix configuration for all interfaces:

ni2-3# show atm addresses
 
Switch Address(es):
  47.009181000000007BF4447801.007BF4447801.00 active
 
Soft VC Address(es):
  47.0091.8100.0000.007b.f444.7801.4000.0c80.0010.00 ATM0/1
  47.0091.8100.0000.007b.f444.7801.4000.0c80.0020.00 ATM0/2
 
ILMI Switch Prefix(es):
  47.0091.8100.0000.007b.f444.7801
 
ILMI Configured Interface Prefix(es):
 
LECS Address(es):

This example displays the ILMI status for ATM interface 0/1:

DSLAM# show atm ilmi-status atm 0/1
 
Interface : ATM0/1 Interface Type : Private NNI
ILMI VCC : (0, 16) ILMI Keepalive : Disabled
Configured Prefix(s) :
47.0091.8100.0000.0003.c386.b301


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Posted: Tue Sep 19 10:47:47 PDT 2000
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