ATM Switch Router Software Configuration Guide, 12.1(7a)EY - Configuring IP over ATM [Cisco Catalyst 8500 Series Multiservice Switch Routers]

Table Of Contents

Configuring IP over ATM

Configuring Classical IP over ATM

Configuring Classical IP over ATM in an SVC Environment

Configuring Classical IP over ATM in a PVC Environment

Mapping a Protocol Address to a PVC Using Static Map Lists

Configuring a PVC-Based Map List

Configuring an SVC-Based Map List

Policy-Based Routing

Policy-Based Routing Restrictions

Configuring IP over ATM

This chapter describes how to configure IP over ATM on the ATM switch router. The primary use of IP over ATM is for inband management of the ATM switch router.

Note This chapter provides advanced configuration instructions for the Catalyst 8540 MSR, Catalyst 8510 MSR, and LightStream 1010 ATM switch routers. For further information about Layer 3 protocols over ATM, refer to the Guide to ATM Technology. For complete descriptions of the commands mentioned in this chapter, refer to the ATM Switch Router Command Reference publication.

This chapter includes the following sections:

• Configuring Classical IP over ATM

• Mapping a Protocol Address to a PVC Using Static Map Lists

• Policy-Based Routing

Configuring Classical IP over ATM

This section describes configuring a port on a ATM switch router to allow a classical IP-over-ATM connection to the ATM switch router's route processor and optional ATM router module.

The following sections describe configuring the ATM switch router for classical IP over ATM in either a switched virtual channel (SVC) or permanent virtual channel (PVC) environment.

Configuring Classical IP over ATM in an SVC Environment

This section describes classical IP over ATM in an SVC environment. It requires configuring only the device's own ATM address and that of a single ATM Address Resolution Protocol (ARP) server into each client device.

For a detailed description of the role and operation of the ATM ARP server, refer to the Guide to ATM Technology.

The ATM switch router can be configured as an ATM ARP client to work with any ATM ARP server conforming to RFC 1577. Alternatively, one of the ATM switch routers in a logical IP subnet (LIS) can be configured to act as the ATM ARP server itself. In that case, it automatically acts as a client as well. The following sections describe configuring the ATM switch router in an SVC environment as either an ATM ARP client or an ATM ARP server.

Configuring as an ATM ARP Client

In an SVC environment, configure the ATM ARP mechanism on the interface by performing the following steps, beginning in global configuration mode:

Command

Purpose

Step 1

Switch(config)# interface atm 0

Switch(config-if)#

or

Switch(config)# interface atm card/subcard/port

Switch(config-if)#

Selects the route processor interface.

or

If you are using the optional Catalyst 8540 MSR enhanced ATM router module, specifies the ATM interface number.

Step 2

Switch(config-if)# atm nsap-address nsap-address

or

Switch(config-if)# atm esi-address esi.selector

Specifies the network service access point (NSAP) ATM address of the interface.

or

Specifies the end-system-identifier (ESI) address of the interface.

Step 3

Switch(config-if)# ip address ip-address mask

Specifies the IP address of the interface.

Step 4

Switch(config-if)# atm arp-server nsap nsap-address

Specifies the ATM address of the ATM ARP server.

Step 5

Switch(config-if)# exit

Switch(config)#

Exits interface configuration mode.

Step 6

Switch(config)# atm route addr-prefix¹ {atm 0 | atm card/subcard/port} internal

Configures a static route through the ATM switch router to the route processor interface, or the optional Catalyst 8540 MSR enhanced ATM router module interface. See the following note.

¹Address prefix is first 19 bytes of the NSAP address.

Note The end system identifier (ESI) address form is preferred in that it automatically handles the advertising of the address. Use the network service access point (NSAP) form of the command when you need to define a full 20-byte unique address with a prefix unrelated to the network prefix on that interface. You only need to specify a static route when configuring an ARP client using an NSAP address.

Note Since the 12.0(1a)W5(5b) release of the system software, addressing the interface on the processor card has changed. The ATM interface is now called atm0, and the Ethernet interface is now called ethernet0. The old formats (atm 2/0/0 and ethernet 2/0/0) are still supported.

NSAP Address Example

Figure 12-1 shows three ATM switch routers and a router connected using classical IP over ATM.

Figure 12-1 Classical IP over ATM Connection Setup

The following example shows how to configure the route processor interface ATM 0 of client A in Figure 12-1, using the NSAP address:
Client A(config)# interface atm 0
Client A(config-if)# atm nsap-address 47.0091.8100.0000.1111.1111.1111.1111.1111.1111.00
Client A(config-if)# ip address 123.233.45.1 255.255.255.0
Client A(config-if)# atm arp-server nsap 47.0091.8100.0000.1111.1111.1111.2222.2222.2222.00
Client A(config-if)# exit
Client A(config)# atm route 47.0091.8100.0000.1111.1111.1111.1111.1111.1111 atm 0 internal
ESI Example

The following example shows how to configure route processor interface ATM 0 of client A in Figure 12-1 using the ESI:
Client A(config)# interface atm 0
Client A(config-if)# atm esi-address 0041.0b0a.1081.40
Client A(config-if)# ip address 123.233.45.1 255.255.255.0
Client A(config-if)# atm arp-server nsap 47.0091.8100.0000.1111.1111.1111.2222.2222.2222.00
Client A(config-if)# exit
Client A(config)# atm route 47.0091.8100.0000.1111.1111.1111.1111.1111.1111 atm 0 internal
Configuring as an ATM ARP Server

Cisco's implementation of the ATM ARP server supports a single, nonredundant server per LIS and one ATM ARP server per subinterface. Thus, a single ATM switch router can support multiple ARP servers by using multiple interfaces.

To configure the ATM ARP server, perform the following steps, beginning in global configuration mode:

Command

Purpose

Step 1

Switch(config)# interface atm 0[.subinterface#]

Switch(config-if)#

or

Switch(config)# interface atm card/subcard/port[.subinterface#]

Switch(config-if)#

Selects the route processor interface.

or

If you are using the optional Catalyst 8540 MSR enhanced ATM router module, specifies the ATM interface number.

Step 2

Switch(config-if)# atm nsap-address nsap-address

or

Switch(config-if)# atm esi-address esi.selector

Specifies the NSAP ATM address of the interface.

or

Specifies the end-system-identifier address of the interface.

Step 3

Switch(config-if)# ip address ip-address mask

Specifies the IP address of the interface.

Step 4

Switch(config-if)# atm arp-server self [time-out minutes]¹

Configures this interface as the ATM ARP server for the logical IP network.

Step 5

Switch(config-if)# atm route addr-prefix² {atm 0 | atm card/subcard/port} internal

Configures a static route through the ATM switch router to the route processor interface, or the optional Catalyst 8540 MSR enhanced ATM router module interface. See the following note.

¹This form of the atm arp-server command indicates that this interface performs the ATM ARP server functions. When you configure the ATM ARP client (described earlier), the atm arp-server command is used—with a different keyword and argument—to identify a different ATM ARP server to the client.

²Address prefix is first 19 bytes of the NSAP address.

Note The ESI address form is preferred in that it automatically handles the advertising of the address. Use the NSAP form of the command when you need to define a full 20-byte unique address with a prefix unrelated to the network prefix on that interface. You only need to specify a static route when configuring an ARP server using an NSAP address.

The idle timer interval is the number of minutes a destination entry listed in the ATM ARP server ARP table can be idle before the server takes any action to timeout the entry.

Example

The following example configures the route processor interface ATM 0 as an ARP server (shown in Figure 12-1):
ARP_Server(config)# interface atm 0
ARP_Server(config-if)# atm esi-address 0041.0b0a.1081.00
ARP_Server(config-if)# atm arp-server self
ARP_Server(config-if)# ip address 123.233.45.2 255.255.255.0
Client A(config)# atm route 47.0091.8100.0000.1111.1111.1111.1111.1111.1111 atm 0 internal
Displaying the IP-over-ATM Interface Configuration

To show the IP-over-ATM interface configuration, use the following EXEC commands:

Command

Purpose

show atm arp-server

Shows the ATM interface ARP configuration.

show atm map

Shows the ATM map list configuration.

Examples

In the following example, the show atm arp-server command displays the configuration of the interface ATM 0:
Switch# show atm arp-server
Note that a '*' next to an IP address indicates an active call
      IP Address        TTL     ATM Address
ATM2/0/0:
    * 10.0.0.5          19:21   4700918100567000000000112200410b0a108140
The following example displays the map-list configuration of the static map and IP-over-ATM interfaces:
Switch# show atm map
Map list ATM2/0/0_ATM_ARP : DYNAMIC
arp maps to NSAP 36.0091810000000003D5607900.0003D5607900.00
        , connection up, VPI=0 VCI=73, ATM2/0/0
ip 5.1.1.98 maps to s 36.0091810000000003D5607900.0003D5607900.00
        , broadcast, connection up, VPI=0 VCI=77, ATM2/0/0
Map list ip : PERMANENT
ip 5.1.1.99 maps to VPI=0 VCI=200
Configuring Classical IP over ATM in a PVC Environment

This section describes how you configure classical IP over ATM in a permanent virtual channel (PVC) environment. The ATM Inverse ARP (InARP) mechanism is applicable to networks that use PVCs, where connections are established but the network addresses of the remote ends are not known. A server function is not used in this mode of operation.

In a PVC environment, configure the ATM InARP mechanism by performing the following steps, beginning in global configuration mode:

Command

Purpose

Step 1

Switch(config)# interface atm 0

Switch(config-if)#

or

Switch(config)# interface atm card/subcard/port

Switch(config-if)#

Selects the route processor interface.

If you are using the optional ATM router module, specifies the ATM interface number.

Step 2

Switch(config-if)# ip address ip-address mask

Specifies the IP address of the interface.

Step 3

Switch(config-if)# atm pvc [0 | 2] vci interface atm card/subcard/port vpi vci encap [aal5mux | aal5snap] [inarp minutes]

Creates a PVC and enables Inverse ARP. The VPI value on interface ATM 0 is 0. The VPI value on an ATM router module interface is 2.

Repeat these tasks for each PVC you want to create.

The inarp minutes interval specifies how often Inverse ARP datagrams are sent on this virtual circuit. The default value is 15 minutes.

Note The ATM ARP and ATM InARP mechanisms work with IP only. All other protocols require map-list command entries to operate.

Example

The following example shows how to configure an IP-over-ATM interface on interface ATM 0, using a PVC with AAL5SNAP encapsulation, inverse ARP set to ten minutes, VPI = 0, and VCI = 100:
Switch(config)# interface atm 0
Switch(config-if)# ip address 11.11.11.11 255.255.255.0
Switch(config-if)# atm pvc 0 100 interface atm 0/0/0 50 100 encap aal5snap inarp 10
Displaying the IP-over-ATM Interface Configuration

To show the IP-over-ATM interface configuration, use the following EXEC command:

Command

Purpose

show atm map

Shows the ATM interface ARP configuration.

Example

The following example displays the map-list configuration of the static map and IP-over-ATM interfaces:
Switch# show atm map
Map list yyy : PERMANENT
ip 1.1.1.2 maps to VPI=0 VCI=200
Map list zzz : PERMANENT
Map list a : PERMANENT
Map list 1 : PERMANENT
Map list ATM2/0/0_ATM_ARP : DYNAMIC
arp maps to NSAP 47.009181005670000000001122.00410B0A1081.40
        , connection up, VPI=0 VCI=85, ATM2/0/0
ip 10.0.0.5 maps to NSAP 47.009181005670000000001122.00410B0A1081.40
        , broadcast, ATM2/0/0
Mapping a Protocol Address to a PVC Using Static Map Lists

The ATM interface supports a static mapping scheme that identifies the ATM address of remote hosts or ATM switch routers. This IP address is specified as a permanent virtual channel (PVC) or as a network service access point (NSAP) address for switch virtual channel (SVC) operation.

The following sections describe configuring both PVC-based and SVC-based map lists on the ATM switch router. For a more detailed discussion of static map lists, refer to the Guide to ATM Technology.

Configurations for both PVC and SVC map lists are described in the following sections:

• Configuring a PVC-Based Map List

• Configuring an SVC-Based Map List

Configuring a PVC-Based Map List

This section describes how to map a PVC to an address, which is a required task if you are configuring a PVC.

You enter mapping commands as groups. You first create a map list and then associate it with an interface. Perform the following steps, beginning in global configuration mode:

Command

Purpose

Step 1

Switch(config-if)# interface atm card/subcard/port[.subinterface#]

Specifies an ATM interface and enters interface configuration mode.

Step 2

Switch(config-if)# ip address ip-address mask

Enters the IP address and subnet mask associated with this interface.

Step 3

Switch(config-if)# map-group name

Enters the map group name associated with this PVC.

Step 4

Switch(config-if)# atm pvc vpi-a vci-a [upc upc] [pd pd] [rx-cttr index] [tx-cttr index] interface atm card/subcard/port[.vpt#] vpi-b vci-b [upc upc] [encap aal-encap]

Configures the PVC.

Step 5

Switch(config-if)# exit

Switch(config)#

Exits interface configuration mode.

Step 6

Switch(config)# ip route ip-address mask forward-ip address

Configures an IP route to the router.

Step 7

Switch(config)# map-list name

Switch(config-map-list)#

Creates a map list by naming it, and enters map-list configuration mode.

Step 8

Switch(config-map-list)# ip ip-address {atm-nsap address | atm-vc vci} [aal5mux encapsulation] [broadcast pseudo-broadcast] [class class-name]

Associates a protocol and address to a specific virtual circuit.

You can create multiple map lists, but only one map list can be associated with an interface. Different map lists can be associated with different interfaces.

Example

Figure 12-2 illustrates a connection configured with a PVC map list.

Figure 12-2 PVC Map List Configuration Example

The following example shows the commands used to configure the connection in Figure 12-2.
Switch(config)# interface atm 0
Switch(config-if)# ip address 1.1.1.1 255.0.0.0
Switch(config-if)# map-group yyy
Switch(config-if)# atm pvc 0 200 interface atm 3/0/0 100 300 encap aal5snap
Switch(config-if)# exit
Switch(config)# ip route 1.1.1.1 255.0.0.0 1.1.1.2
Switch(config)# map-list yyy
Switch(config-map-list)# ip 1.1.1.2 atm-vc 200
Displaying the Map-List Interface Configuration

To show the map-list interface configuration, use the following EXEC command:

Command

Purpose

show atm map

Shows the ATM interface map-list configuration.

Example

The following example displays the map-list configuration at interface ATM 0:
Switch# show atm map
Map list yyy : PERMANENT
ip 1.1.1.2 maps to VPI=0 VCI=200
Configuring an SVC-Based Map List

This section describes how to map an SVC to an NSAP address. This is a required task if you are configuring an SVC.

You enter mapping commands as groups. You first create a map list and then associate it with an interface. Perform the following steps, beginning in global configuration mode:

Command

Purpose

Step 1

Switch(config)# interface atm card/subcard/port[.subinterface#]

Switch(config-if)#

Specifies an ATM interface and enters interface configuration mode.

Step 2

Switch(config-if)# ip address ip-address mask

Enters the IP address and subnet mask associated with this interface.

Step 3

Switch(config-if)# atm nsap-address nsap-address

Configures the interface NSAP address.

Step 4

Switch(config-if)# map-group name

Enters the map-group name associated with this PVC.

Step 5

Switch(config-if)# exit

Switch(config)#

Exits interface configuration mode.

Step 6

Switch(config)# map-list name

Switch(config-map-list)#

Creates a map list by naming it, and enters map-list configuration mode.

Step 7

Switch(config-map-list)# ip ip-address {atm-nsap address | atm-vc vci} [aal5mux encapsulation] [broadcast pseudo-broadcast] [class class-name]

Associates a protocol and address to a specific virtual circuit.

You can create multiple map lists, but only one map list can be associated with an interface. Different map lists can be associated with different interfaces.

Examples

Figure 12-3 illustrates an SVC connection configured with a map list.

Figure 12-3 SVC Map-List Configuration Example

The following example shows the commands used to configure the connection in Figure 12-3:
Switch(config)# interface atm 0
Switch(config-if)# ip address 1.1.1.1 255.0.0.0
Switch(config-if)# atm nsap-address 47.0091.1111.1111.1111.1111.1111.1111.1111.1111.00
Switch(config-if)# map-group zzz
Switch(config-if)# exit
Switch(config)# map-list zzz
Switch(config-map-list)# ip 1.1.1.2 atm-nsap 39.1533.2222.2222.2222.2222.2222.2222.2222.2222.00
Displaying the Map-List Interface Configuration

To show the map-list interface configuration, use the following EXEC command:

Command

Purpose

show atm map

Shows the ATM interface map-list configuration.

Example

The following example displays the map-list configuration at interface ATM 0:
Switch# show atm map
Map list zzz : PERMANENT
ip 1.1.1.2 maps to NSAP AC.153322222222222222222222.222222222222.00
Policy-Based Routing

Policy-based routing (PBR) allows you to do the following:

•Classify traffic based on extended access list criteria.

•Set IP Precedence bits.

•Route specific traffic to engineered paths, which may be required to allow a specific QoS service through the network.

Classification of traffic through PBR is based on standard or named Access Control Lists (ACLs) and IP packet length. Some possible applications for policy routing are to provide equal access, protocol-sensitive routing, source-sensitive routing, routing based on interactive versus batch traffic, or routing based on dedicated links.

For more information on policy-based routing, including configuration examples, refer to the Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.1.

Policy-Based Routing Restrictions

The following restrictions apply to policy-based routing (PBR) on the Catalyst 8540 MSR and the Catalyst 8540 CSR:

•PBR is supported only on the Enhanced Gigabit interface.

•The IP interface for egress must be supported by the Catalyst 8540 MSR and the Catalyst 8540 CSR.

•Fast-switched PBR cannot be enabled because the Catalyst 8540 is a line rate switch.

•When configuring IP QoS to rewrite precedence and PBR to rely on precedence set by an ACL, the classification for PBR uses the original packet precedence, not the rewritten IP QoS value.

•Changes in the TCAM space for a PBR region must be specified with the sdm policy size command. The changes take effect upon reboot. The default PBR TCAM size is 0.

•The following commands are supported:

–match ip address {access-list-number | name} [...access-list-number | name]

–match length min max

Note The IP packet length range supported in a route map is 0-1535. A maximum of three non-overlapping length ranges are allowed per interface, including sub-interfaces.

•The following set command options are supported for PBR:

–ip precedence

–ip next-hop

–interface

–interface null0.

Note Due to platform limitations, the set interface null0 command does not generate an "unreachable" message.

•The following commands are not supported:

–set ip default next-hop

–set ip default interface

•When you configure a policy to rewrite precedence with a next hop interface, the precedence is rewritten only when the packet flows via the supported PBR path. If the next-hop is not accessible, the original precedence is retained since the packet flows via DBR (destination based routing). Figure 12-4 illustrates the supported PBR path for IP packet flow on the Catalyst 8540 MSR and the Catalyst 8540 CSR.

Figure 12-4 IP Packet Flow for PBR