Configuration Tasks
This section describes the most common configurations for the ATM SPAs on Cisco ASR 1000 Series Router. For information about managing your system images and configuration files, refer to the following:
Required Configuration Tasks
Some of the required configuration commands implement default values that might or might not be appropriate for your network. If the default value is correct for your network, then you do not need to configure the command.
To perform the basic configuration on a primary ATM interface, complete the following steps beginning in global configuration mode:
![]() Note |
No data path is supported on the primary ATM interface for ATM SPAs on the Cisco ASR 1000 Series Aggregation Services Routers. |
SUMMARY STEPS
- Router(config)# interface atm slot/ subslot/ port
- Router(config-if)# atm clock internal
- Router(config-if)# no atm ilmi-keepalive
- Router(config-if)# description string
- Router(config-if)# no shutdown
- Repeat Step 1 through Step 5 for each port on the ATM SPA to be configured.
- Router(config-if)# end
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 |
Router(config)# interface atm slot/ subslot/ port |
Enters interface configuration mode for the indicated port on the specified ATM SPA. |
Step 2 |
Router(config-if)# atm clock internal |
(Required in back-to-back router configuration) Configures the interface for internal clocking. The default clocking on all ATM interfaces is line clocking, or retrieval of the clock signal from the receive data stream. Therefore, you must configure an internal clock when the ATM link is in back-to-back configuration between two routers. In this case, one end of the link must be configured to use the internal clock. You do not need to configure clocking when the router is connected to a switch, which also uses line clocking by default. |
Step 3 |
Router(config-if)# no atm ilmi-keepalive |
Integrated Local Management Interface (ILMI) is not supported on ATM SPAs on the Cisco ASR 1000 Series Aggregation Services Routers. This command is the default for all ATM SPAs on the Cisco ASR 1000 Series Aggregation Services Routers. |
Step 4 |
Router(config-if)# description string |
(Optional) Assigns an arbitrary string, up to 80 characters long, to the interface. This string can identify the purpose or owner of the interface, or any other information that might be useful for monitoring and troubleshooting. |
Step 5 |
Router(config-if)# no shutdown |
Enables the interface. |
Step 6 |
Repeat Step 1 through Step 5 for each port on the ATM SPA to be configured. |
|
Step 7 |
Router(config-if)# end Example:
|
Exits interface configuration mode and returns to privileged EXEC mode. |
Required Configuration Tasks
To perform the basic configuration on each subinterface, use the following procedure beginning in global configuration mode:
SUMMARY STEPS
- Router(config)# interface atm slot/ subslot/ port. sub-interface [point-to-point | multipoint ]
- Router(config-subif)# ip address address mask [secondary ]
- Router(config-if)# pvc [name ] vpi /vci
- Router(config-subif)# description string
- Router(config-subif)# no shutdown
- Repeat Step 1 through Step 5for each ATM SPA subinterface to be configured.
- Router(config-subif)# end
DETAILED STEPS
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
Router(config)# interface atm slot/ subslot/ port. sub-interface [point-to-point | multipoint ] |
Enters subinterface configuration mode pertaining to the specified subinterface, where:
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Step 2 |
Router(config-subif)# ip address address mask [secondary ] |
Assigns the specified IP address and subnet mask to the interface. Repeat the command with the optional secondary keyword to assign additional, secondary IP addresses to the port. |
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Step 3 |
Router(config-if)# pvc [name ] vpi /vci |
Configures a new ATM PVC by assigning its VPI/VCI numbers and enters ATM VC configuration mode. The valid values for vpi /vci are:
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Step 4 |
Router(config-subif)# description string |
(Optional) Assigns an arbitrary string, up to 80 characters long, to the interface. This string can identify the purpose or owner of the interface, or any other information that might be useful for monitoring and troubleshooting. |
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Step 5 |
Router(config-subif)# no shutdown |
Enables the interface. |
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Step 6 |
Repeat Step 1 through Step 5for each ATM SPA subinterface to be configured. |
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Step 7 |
Router(config-subif)# end Example:
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Exits interface configuration mode and returns to privileged EXEC mode. |
Specifying the Interface Address on a SPA
Up to four ATM SPAs can be installed in a SIP. SPA interface ports begin numbering with “0” from left to right. Single-port SPAs use only the port number 0. To configure or monitor SPA interfaces, you need to specify the physical location of the SIP, SPA, and interface in the CLI. The interface address format is slot/ subslot/ port , where:
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slot—Specifies the chassis slot number in the Cisco ASR 1000 Series Router where the SIP is installed.
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subslot—Specifies the secondary slot of the SIP where the SPA is installed.
-
port—Specifies the number of the individual interface port on a SPA.
The following example shows how to specify the first interface (0) on a SPA installed in the first subslot of a SIP (0) installed in chassis slot 3:
Router(config)# interface serial 3/0/0
This command shows a serial SPA as a representative example, however the same slot/ subslot/ port format is similarly used for other SPAs (such as ATM and POS) and other non-channelized SPAs.
For more information about identifying slots and subslots, see the “Identifying Slots and Subslots for the SIPs and SPAs” section in the Configuring the SIP chapter.
Modifying the Interface MTU Size
The maximum transmission unit (MTU) values might need to be reconfigured from their defaults on the ATM SPAs to match the values used in your network.
![]() Note |
In the Cisco ASR 1000 Series Route Processor 1 (RP1), 2RU and 2RU-Fixed chassis, the MTU size for the Management Ethernet interface (interface gigabitethernet 0) is limited to 2370 bytes. |
Interface MTU Configuration Guidelines
When configuring the interface MTU size on an ATM SPA, consider the following guidelines.
The Cisco IOS software supports several types of configurable MTU options at different levels of the protocol stack. You should ensure that all MTU values are consistent to avoid unnecessary fragmentation of packets. These MTU values are the following:
- Interface MTU—Configured on a per-interface basis and defines the maximum packet size (in bytes) that is allowed for traffic received on the network. The ATM SPA checks traffic coming in from the network and drops packets that are larger than this maximum value. Because different types of Layer 2 interfaces support different MTU values, choose a value that supports the maximum possible packet size that is possible in your particular network topology.
- IP MTU—Configured on a per-interface or per-subinterface basis and determines the largest maximum IP packet size (in bytes) that is allowed on the IP network without being fragmented. If an IP packet is larger than the IP MTU value, the ATM SPA fragments it into smaller IP packets before forwarding it on to the next hop.
- Multiprotocol Label Switching (MPLS) MTU—Configured on a per-interface or per-subinterface basis and defines the MTU value for packets that are tagged with MPLS labels or tag headers. When an IP packet that contains MPLS labels is larger than the MPLS MTU value, the ATM SPA fragments it into smaller IP packets. When a non-IP packet that contains MPLS labels is larger than the MPLS MTU value, the ATM SPA drops it.
All devices on a particular physical medium must have the same MPLS MTU value to allow proper MPLS operation. Because MPLS labels are added on to the existing packet and increase the packet’s size, choose appropriate MTU values so as to avoid unnecessarily fragmenting MPLS-labeled packets.
If the IP MTU or MPLS MTU values are currently the same size as the interface MTU, changing the interface MTU size also automatically sets the IP MTU or MPLS MTU values to the new value. Changing the interface MTU value does not affect the IP MTU or MPLS MTU values if they are not currently set to the same size as the interface MTU.
Different encapsulation methods and the number of MPLS MTU labels add additional overhead to a packet. For example, Subnetwork Access Protocol (SNAP) encapsulation adds an 8-byte header, and each MPLS label adds a 4-byte header. Consider the maximum possible encapsulations and labels that are to be used in your network when choosing the MTU values.
![]() Tip |
The MTU values on the local ATM SPA interfaces must match the values being used in the ATM network and remote ATM interface. Changing the MTU values on an ATM SPA does not reset the local interface, but be aware that other platforms and ATM SPAs do reset the link when the MTU value changes. This could cause a momentary interruption in service, so we recommend changing the MTU value only when the interface is not being used. |
![]() Note |
The interface MTU value on the ATM SPA also determines which packets are recorded as “giants” in the show interfaces atm command. The interface considers a packet to be a giant packet when it is more than 24 bytes larger than the interface MTU size. For example, if using an MTU size of 1500 bytes, the interface increments the giants counter when it receives a packet larger than 1524 bytes. |
Interface MTU Configuration Task
To change the MTU values on the ATM SPA interfaces, use the following procedure beginning in global configuration mode:
SUMMARY STEPS
- Do one of the following:
- Router(config)# interface atm slot/ subslot/ port
- Router(config)# interface atm slot/ subslot/ port. subinterface
- Router(config-if)# mtu bytes
- Router(config-if)# ip mtu bytes
- Router(config-if)# mpls mtu bytes
- Router(config-if)# end
DETAILED STEPS
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
Do one of the following:
|
Enters interface configuration mode for the indicated port on the specified ATM SPA, where:
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Step 2 |
Router(config-if)# mtu bytes |
(Optional) Configures the maximum transmission unit (MTU) size for the interface. The valid range for bytes is from 64 to 9216 bytes, with a default of 4470 bytes. As a general rule, do not change the MTU value unless you have a specific application need to do so.
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Step 3 |
Router(config-if)# ip mtu bytes Example:
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(Optional) Configures the MTU value, in bytes, for IP packets on this interface. The valid range for an ATM SPA is 64 to 9288, with a default value equal to the MTU value configured in Step 2. |
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Step 4 |
Router(config-if)# mpls mtu bytes Example:
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(Optional) Configures the MTU value, in bytes, for MPLS-labeled packets on this interface. The valid range for an ATM SPA is 64 to 9216 bytes, with a default value equal to the MTU value configured in Step 2. |
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Step 5 |
Router(config-if)# end Example:
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Exits interface configuration mode and returns to privileged EXEC mode. |
Verifying the MTU Size
To verify the MTU sizes for an interface, use the show interfaces , show ip interface , and show mpls interface commands, as in the following examples:
![]() Note |
The output of the show interfaces atm command can display configuration of AAL5 encapsulation, but only AAL0 is supported on the Cisco ASR 1000 Series Aggregation Services Routers. |
Router# show interfaces atm 0/2/2
ATM0/2/2 is up, line protocol is up
Hardware is SPA-3XOC3-ATM-V2, address is 001a.3044.7522 (bia 001a.3044.7522)
MTU 4470 bytes, sub MTU 4470, BW 149760 Kbit, DLY 80 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ATM, loopback not set
Keepalive not supported
Encapsulation(s): AAL5 AAL0
4095 maximum active VCs, 1 current VCCs
VC Auto Creation Disabled.
VC idle disconnect time: 300 seconds
4 carrier transitions
Last input never, output 00:04:11, output hang never
Last clearing of "show interface" counters never
Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
5 packets input, 540 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
5 packets output, 540 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 output buffer failures, 0 output buffers swapped out
Router# show ip interface atm 0/2/2.1
ATM0/2/2.1 is up, line protocol is up
Internet address is 10.4.0.2/24
Broadcast address is 255.255.255.255
Address determined by setup command
MTU is 4470 bytes
Helper address is not set
Directed broadcast forwarding is disabled
Outgoing access list is not set
Inbound access list is not set
Proxy ARP is enabled
Local Proxy ARP is disabled
Security level is default
Split horizon is disabled
ICMP redirects are always sent
ICMP unreachables are always sent
ICMP mask replies are never sent
IP fast switching is enabled
IP Flow switching is disabled
IP CEF switching is enabled
IP Distributed switching is disabled
IP CEF switching turbo vector
IP Null turbo vector
Associated unicast routing topologies:
Topology "base", operation state is UP
IP multicast fast switching is enabled
IP multicast distributed fast switching is disabled
IP route-cache flags are Fast, CEF
Router Discovery is disabled
IP output packet accounting is disabled
IP access violation accounting is disabled
TCP/IP header compression is disabled
RTP/IP header compression is disabled
Probe proxy name replies are disabled
Policy routing is disabled
Network address translation is disabled
BGP Policy Mapping is disabled
Input features: MCI Check
WCCP Redirect outbound is disabled
WCCP Redirect inbound is disabled
WCCP Redirect exclude is disabled
Router# show mpls interface atm 0/3/2.1
Interface IP Tunnel BGP Static Operational
ATM0/3/2.1 Yes (ldp) No No No Yes
CE1#sh mpls int atm0/3/2.1 det
Interface ATM0/3/2.1:
IP labeling enabled (ldp):
Interface config
LSP Tunnel labeling not enabled
BGP labeling not enabled
MPLS operational
MTU = 4470
To view the maximum possible size for datagrams passing out the interface using the configured MTU value, use the show atm interface atm command:
Router# show atm interface atm 0/2/2
Interface ATM0/2/2:
AAL enabled: AAL0, Maximum VCs: 4095, Current VCCs: 1
Max. Datagram Size: 4528
PLIM Type: SONET - 155000Kbps, TX clocking: LINE
Cell-payload scrambling: ON
sts-stream scrambling: ON
5 input, 5 output, 0 IN fast, 0 OUT fast, 0 out drop
Avail bw = 149760
Config. is ACTIVE
Creating a Permanent Virtual Circuit
To use a permanent virtual circuit (PVC), configure the PVC in both the router and the ATM switch. PVCs remain active until the circuit is removed from either configuration. To create a PVC on the ATM interface and enter interface ATM VC configuration mode, perform the following procedure beginning in global configuration mode:
SUMMARY STEPS
- Router(config)# interface atm slot/ subslot/ port. subinterface
- Router(config-if)# ip address address mask
- Router(config-if)# atm tx-latency milliseconds
- Router(config-if)# pvc [name ] vpi /vci
- Router(config-if-atm-vc)# protocol protocol {protocol-address | inarp } [[no ] broadcast ]
- Router(config-if-atm-vc)# inarp minutes
- Router(config-if-atm-vc)# encapsulation {aal5mux protocol | aal5nlpid | aal5snap }
- Router(config-if-atm-vc)# tx-limit buffers
- Router(config-if-atm-vc)# end
DETAILED STEPS
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
Router(config)# interface atm slot/ subslot/ port. subinterface |
Enters subinterface configuration mode pertaining to the specified port on the ATM SPA, where:
|
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Step 2 |
Router(config-if)# ip address address mask |
Assigns the specified IP address and subnet mask to the interface or subinterface. |
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Step 3 |
Router(config-if)# atm tx-latency milliseconds |
(Optional) Configures the default transmit latency for VCs on this ATM SPA interface. The valid range for milliseconds is from 1 to 200, with a default of 100 milliseconds. |
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Step 4 |
Router(config-if)# pvc [name ] vpi /vci |
Configures a new ATM PVC by assigning its VPI/VCI numbers and enters ATM VC configuration mode. The valid values for vpi /vci are:
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Step 5 |
Router(config-if-atm-vc)# protocol protocol {protocol-address | inarp } [[no ] broadcast ] |
Configures the PVC for a particular protocol and maps it to a specific protocol-address .
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Step 6 |
Router(config-if-atm-vc)# inarp minutes |
(Optional) If using Inverse ARP, configures how often the PVC transmits Inverse ARP requests to confirm its address mapping. The valid range is 1 to 60 minutes, with a default of 15 minutes. |
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Step 7 |
Router(config-if-atm-vc)# encapsulation {aal5mux protocol | aal5nlpid | aal5snap } |
(Optional) Configures the ATM adaptation layer (AAL) and encapsulation type, where:
Possible values for the protocol argument are as follows:
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Step 8 |
Router(config-if-atm-vc)# tx-limit buffers |
(Optional) Specifies the number of transmit buffers for this VC. The valid range is from 1 to 57343, with a default value that is based on the current VC line rate and on the latency value that is configured with the atm tx-latency command. |
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Step 9 |
Router(config-if-atm-vc)# end |
Exits ATM VC configuration mode and returns to privileged EXEC mode. |
Verifying a PVC Configuration
To verify the configuration of a particular PVC, use the show atm pvc command:
Router# show atm pvc
VCD / Peak Av/Min Burst
Interface Name VPI VCI Type Encaps SC Kbps Kbps Cells St
0/2/2.1 1 2 32 PVC SNAP UBR 149760 UP
![]() Tip |
To verify the configuration and current status of all PVCs on a particular interface, you can also use the show atm vc interface atm command. |
Creating a PVC on a Point-to-Point Subinterface
Use point-to-point subinterfaces to provide each pair of routers with its own subnet. When you create a PVC on a point-to-point subinterface, the router assumes it is the only point-to-point PVC that is configured on the subinterface, and it forwards all IP packets with a destination IP address in the same subnet to this VC. To configure a point-to-point PVC, perform the following procedure beginning in global configuration mode:
SUMMARY STEPS
- Router(config)# interface atm slot/ subslot/ port. subinterface point-to-point
- Router(config-subif)# ip address address mask
- Router(config-subif)# pvc [name ] vpi /vci
- Router(config-if-atm-vc)# protocol protocol protocol-address [[no ] broadcast ]
- Router(config-if-atm-vc)# encapsulation {aal5mux protocol | aal5nlpid | aal5snap }
- Router(config-if)# end
DETAILED STEPS
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
Router(config)# interface atm slot/ subslot/ port. subinterface point-to-point |
Creates the specified point-to-point subinterface on the given port on the specified ATM SPA, and enters subinterface configuration mode, where:
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Step 2 |
Router(config-subif)# ip address address mask |
Assigns the specified IP address and subnet mask to this subinterface. |
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Step 3 |
Router(config-subif)# pvc [name ] vpi /vci |
Configures a new ATM PVC by assigning its VPI/VCI numbers and enters ATM VC configuration mode. The valid values for vpi /vci are:
|
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Step 4 |
Router(config-if-atm-vc)# protocol protocol protocol-address [[no ] broadcast ] |
Configures the PVC for a particular protocol and maps it to a specific protocol-address .
The protocol command also has an inarp option, but this option is not meaningful on point-to-point PVCs that use a manually configured address. |
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Step 5 |
Router(config-if-atm-vc)# encapsulation {aal5mux protocol | aal5nlpid | aal5snap } |
(Optional) Configures the ATM adaptation layer (AAL) and encapsulation type, where:
|
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Step 6 |
Router(config-if)# end |
Exits interface configuration mode and returns to privileged EXEC mode. |
What to do next
![]() Tip |
To verify the configuration and current status of all PVCs on a particular interface, you can also use the show atm vc interface atm command. |
Configuring a PVC on a Multipoint Subinterface
Creating a multipoint subinterface allows you to create a point-to-multipoint PVC that can be used as a broadcast PVC for all multicast requests. To create a PVC on a multipoint subinterface, use the following procedure beginning in global configuration mode:
SUMMARY STEPS
- Router(config)# interface atm slot/ subslot/ port. subinterface multipoint
- Router(config-subif)# ip address address mask
- Router(config-subif)# no ip directed-broadcast
- Router(config-subif)# pvc [name ] vpi /vci
- Router(config-if-atm-vc)# protocol protocol {protocol-address | inarp } broadcast
- Router(config-if-atm-vc)# inarp minutes
- Router(config-if-atm-vc)# encapsulation {aal5mux protocol | aal5nlpid | aal5snap }
- Router(config-if-atm-vc)# end
DETAILED STEPS
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
Router(config)# interface atm slot/ subslot/ port. subinterface multipoint |
Creates the specified point-to-multipoint subinterface on the given port on the specified ATM SPA, and enters subinterface configuration mode, where:
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Step 2 |
Router(config-subif)# ip address address mask |
Assigns the specified IP address and subnet mask to this subinterface. |
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Step 3 |
Router(config-subif)# no ip directed-broadcast |
(Optional) Disables the forwarding of IP directed broadcasts, which are sometimes used in denial of service (DOS) attacks. |
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Step 4 |
Router(config-subif)# pvc [name ] vpi /vci |
Configures a new ATM PVC by assigning its VPI/VCI numbers and enters ATM VC configuration mode. The valid values for vpi /vci are:
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Step 5 |
Router(config-if-atm-vc)# protocol protocol {protocol-address | inarp } broadcast |
Configures the PVC for a particular protocol and maps it to a specific protocol-address .
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Step 6 |
Router(config-if-atm-vc)# inarp minutes |
(Optional) If using Inverse ARP, configures how often the PVC transmits Inverse ARP requests to confirm its address mapping. The valid range is 1 to 60 minutes, with a default of 15 minutes. |
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Step 7 |
Router(config-if-atm-vc)# encapsulation {aal5mux protocol | aal5nlpid | aal5snap } |
(Optional) Configures the ATM adaptation layer (AAL) and encapsulation type, where:
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Step 8 |
Router(config-if-atm-vc)# end |
Exits interface configuration mode and returns to privileged EXEC mode. |
Verifying a Multipoint PVC Configuration
To verify the configuration of a particular PVC, use the show atm pvc command:
Router# show atm pvc 1/120
ATM3/1/0.120: VCD: 1, VPI: 1, VCI: 120
UBR, PeakRate: 149760
AAL5-LLC/SNAP, etype:0x0, Flags: 0xC20, VCmode: 0x0
OAM frequency: 0 second(s), OAM retry frequency: 1 second(s)
OAM up retry count: 3, OAM down retry count: 5
OAM Loopback status: OAM Disabled
OAM VC status: Not Managed
ILMI VC status: Not Managed
InARP frequency: 15 minutes(s)
Transmit priority 3
InPkts: 1394964, OutPkts: 1395069, InBytes: 1833119, OutBytes: 1838799
InPRoc: 1, OutPRoc: 1, Broadcasts: 0
InFast: 0, OutFast: 0, InAS: 94964, OutAS: 95062
InPktDrops: 0, OutPktDrops: 0
CrcErrors: 0, SarTimeOuts: 0, OverSizedSDUs: 0, LengthViolation: 0, CPIErrors: 0
Out CLP=1 Pkts: 0
OAM cells received: 0
F5 InEndloop: 0, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI: 0
F4 InEndloop: 0, F4 InSegloop: 0, F4 InAIS: 0, F4 InRDI: 0
OAM cells sent: 0
F5 OutEndloop: 0, F5 OutSegloop: 0, F5 OutRDI: 0
F4 OutEndloop: 0, F4 OutSegloop: 0, F4 OutRDI: 0
OAM cell drops: 0
Status: UP
![]() Note |
To verify the configuration and current status of all PVCs on a particular interface, you can also use the show atm vc interface atm command. |
Configuring a Range of PVCs on a Multipoint Subinterface
Beginning in Cisco IOS XE Release 2.5, you can configure a range of PVCs on an ATM multipoint subinterface.
To create a range of PVCs on a multipoint subinterface, use the following procedure beginning in global configuration mode:
SUMMARY STEPS
- Router(config)# interface atm slot/ subslot/ port. subinterface multipoint
- Router(config-subif)# range [range-name ] pvc [start-vpi/ ]start-vci [end-vpi/ ]end-vci
- Once you configure the PVC range, you can configure other commands, such as the protocol command, for all PVCs in the specified range, and you also can go on to define options for individual PVCs using the pvc-in-range
- Router(config-if- atm-range-pvc)# pvc-in-range [ name ] [ vpi/ vci ]
- Once you specify a specific PVC in the range, you can continue to configure options that are specific to that PVC, such as the class-vc command.
- Router(config-if-atm-vc-range-pvc)# end
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 |
Router(config)# interface atm slot/ subslot/ port. subinterface multipoint |
Creates the specified point-to-multipoint subinterface on the given port on the specified ATM SPA, and enters subinterface configuration mode, where:
|
Step 2 |
Router(config-subif)# range [range-name ] pvc [start-vpi/ ]start-vci [end-vpi/ ]end-vci |
Configures multiple PVCs in the specified range and enters ATM PVC range configuration mode, where:
|
Step 3 |
Once you configure the PVC range, you can configure other commands, such as the protocol command, for all PVCs in the specified range, and you also can go on to define options for individual PVCs using the pvc-in-range |
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Step 4 |
Router(config-if- atm-range-pvc)# pvc-in-range [ name ] [ vpi/ vci ] |
(Optional) Defines an individual PVC within a PVC range, where:
|
Step 5 |
Once you specify a specific PVC in the range, you can continue to configure options that are specific to that PVC, such as the class-vc command. |
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Step 6 |
Router(config-if-atm-vc-range-pvc)# end |
Exits ATM PVC range configuration mode and returns to privileged EXEC mode. |
Configuring Traffic Parameters for PVCs
After creating a PVC, you can also configure it for the type of traffic quality of service (QoS) class to be used over the circuit:
- Constant Bit Rate (CBR)—Configures the CBR service class and specifies the average cell rate for the PVC.
- Unspecified Bit Rate (UBR)—Configures the UBR service class and specifies the output peak rate (PCR) for the PVC. This is the default configuration.
- Variable Bit Rate–Non-real Time (VBR-nrt)—Configures the VBR-nrt service class and specifies the output PCR, output sustainable cell rate (SCR), and output maximum burst size (MBS) for the PVC.
- Variable Bit Rate–Real Time (VBR-rt)—Configures the VBR-rt service class and the peak rate and average rate burst for the PVC.
Each service class is assigned a different transmit priority, which the Cisco ASR 1000 Series Router uses to determine which queued cell is chosen to be transmitted out of an interface during any particular cell time slot. This ensures that real-time QoS classes have a higher likelihood of being transmitted during periods of congestion. THe following table lists the ATM QoS classes and their default transmit priorities.
Service Category |
Transmit Priority |
---|---|
CBR |
0 (highest) |
VBR-rt |
1 |
VBR-nrt |
2 |
UBR |
3 |
You can configure a PVC for only one QoS service class. If you enter more than one type, only the most recently configured QoS class takes effect on the circuit.
To configure the traffic parameters for a PVC, perform the following procedure beginning in global configuration mode:
SUMMARY STEPS
- Router(config)# interface atm slot/ subslot/ port or Router(config)# interface atm slot/ subslot/ port. subinterface [multipoint | point-to-point ]
- Router(config-if)# pvc [name ] vpi /vci
- Router(config-if-atm-vc)# cbr rate
- Router(config-if-atm-vc)# ubr output-pcr
- Router(config-if-atm-vc)# vbr-nrt output-pcr output-scr output-mbs
- Router(config-if-atm-vc)# vbr-rt pcr scr burst
- Repeat Step 2 through Step 3 for each PVC to be configured.
- Router(config-if-atm-vc)# end
DETAILED STEPS
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
Router(config)# interface atm slot/ subslot/ port or Router(config)# interface atm slot/ subslot/ port. subinterface [multipoint | point-to-point ] |
Enters interface or subinterface configuration mode for the indicated port on the specified ATM SPA, where:
|
||
Step 2 |
Router(config-if)# pvc [name ] vpi /vci |
Specifies the PVC to be configured, and enters PVC configuration mode, where:
|
||
Step 3 |
Router(config-if-atm-vc)# cbr rate |
Configures constant bit rate (CBR) quality of service (QoS) and average cell rate for the PVC:
|
||
Step 4 |
|
|
||
Step 5 |
Router(config-if-atm-vc)# ubr output-pcr |
Configures unspecified bit rate (UBR) quality of service (QoS) and peak cell rate (PCR) for the PVC:
|
||
Step 6 |
Router(config-if-atm-vc)# vbr-nrt output-pcr output-scr output-mbs |
Configures the variable bit rate–nonreal time (VBR-nrt) QoS, the peak cell rate (PCR), sustainable cell rate (SCR), and maximum burst cell size (MBS) for the PVC:
|
||
Step 7 |
|
|
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Step 8 |
Router(config-if-atm-vc)# vbr-rt pcr scr burst |
Configures the variable bit rate–real time (VBR-rt) QoS, and the PCR, average cell rate (ACR), and burst cell size (BCS) for the PVC:
|
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Step 9 |
Repeat Step 2 through Step 3 for each PVC to be configured. |
|||
Step 10 |
Router(config-if-atm-vc)# end |
Exits PVC configuration mode and returns to privileged EXEC mode. |
Verifying the Traffic Parameter Configuration
Use the show atm vc command to verify the configuration of the traffic parameters for a PVC:
Router# show
atm vc
Codes: DN - DOWN, IN - INACTIVE
VCD / Peak Av/Min Burst
Interface Name VPI VCI Type Encaps SC Kbps Kbps Cells St
0/2/2.1 1 2 32 PVC SNAP UBR 149760 UP
To verify the configuration of all PVCs on an interface, use the show atm vc interface atm command:
Router# show atm vc interface atm 0/2/2.1
VCD / Peak Av/Min Burst
Interface Name VPI VCI Type Encaps SC Kbps Kbps Cells St
0/2/2.1 1 2 32 PVC SNAP UBR 149760 UP
Configuring Virtual Circuit Classes
When multiple PVCs use the same or similar configurations, you can simplify the Cisco ASR 1000 Series Router’s configuration file by creating virtual circuit (VC) classes. Each VC class acts as a template, which you can apply to an ATM subinterface, or to individual PVCs.
When you apply a VC class to an ATM subinterface, all PVCs created on that subinterface inherit the VC class configuration. When you apply a VC class to an individual PVC, that particular PVC inherits the class configuration.
You can then customize individual PVCs with further configuration commands. Any commands that you apply to individual PVCs take precedence over those of the VC class that were applied to the interface or to the PVC.
To create and configure a VC class, and then apply it to a subinterface or individual PVC, use the following procedure beginning in global configuration mode:
SUMMARY STEPS
- Router(config)# vc-class atm vc-class-name
- Router(config-vc-class)# configuration-commands
- Do one of the following:
- Router(config-vc-class)# interface atm slot/ subslot/ port
- Router(config-vc-class)# interface atm slot/ subslot/ port. subinterface [multipoint | point-to-point ]
- Do one of the following:
- Router(config-if)# class-int vc-class-name
- Router(config-subif)# class-int vc-class-name
- Do one of the following:
- Router(config-if)# pvc [name ] vpi /vci
- Router(config-subif)# pvc [name ] vpi /vci
- Router(config-if-atm-vc)# class-vc vc-class-name
- Router(config-if-atm-vc)# configuration-commands
- Router(config-if)# end
DETAILED STEPS
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
Router(config)# vc-class atm vc-class-name |
Creates an ATM virtual circuit (VC) class and enters VC-class configuration mode.
|
||
Step 2 |
Router(config-vc-class)# configuration-commands |
Enter any PVC configuration commands for this VC class. |
||
Step 3 |
Do one of the following:
|
Enters subinterface configuration mode pertaining to the specified ATM subinterface. |
||
Step 4 |
Do one of the following:
|
(Optional) Applies a VC class on the ATM subinterface. This class then applies to all PVCs that are created on that interface.
|
||
Step 5 |
Do one of the following:
|
Specifies the PVC to be configured, and enters PVC configuration mode, where:
|
||
Step 6 |
Router(config-if-atm-vc)# class-vc vc-class-name |
Assigns the specified VC class to this PVC.
|
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Step 7 |
Router(config-if-atm-vc)# configuration-commands |
Any other VC configuration commands to be applied to this particular PVC. Commands that are applied to the individual PVC supersede any conflicting commands that were specified in the VC class. |
||
Step 8 |
Router(config-if)# end |
Exits interface configuration mode and returns to privileged EXEC mode. |
Verifying the Virtual Circuit Class Configuration
To verify the virtual circuit class configuration, use the show atm vc command:
Router# show atm vc
Codes: DN - DOWN, IN - INACTIVE
VCD / Peak Av/Min Burst
Interface Name VPI VCI Type Encaps SC Kbps Kbps Cells St
0/2/2.1 1 2 32 PVC SNAP UBR 149760 UP
Configuring SONET and SDH Framing
The default framing on the ATM OC-3 SPAs is SONET, but the interfaces also support SDH framing.
![]() Note |
In ATM environments, the key difference between SONET and SDH framing modes is the type of cell transmitted when no user or data cells are available. The ATM forum specifies the use of idle cells when unassigned cells are not being generated. More specifically, in Synchronous Transport Module-X (STM-X) mode, an ATM interface sends idle cells for cell-rate decoupling. In Synchronous Transport Signal-Xc (STS-Xc) mode, the ATM interface sends unassigned cells for cell-rate decoupling. |
To change the framing type and configure optional parameters, perform the following procedure beginning in global configuration mode:
SUMMARY STEPS
- Router(config)# interface atm slot/ subslot/ port
- Router(config-if)# atm clock internal
- Router(config-if)# atm framing {sdh | sonet }
- Router(config-if)# [no ] atm sonet report {all | b1-tca | b2-tca | b3-tca | default | lais | lrdi | pais | plop | pplm | prdi | ptim | puneq | sd-ber | sf-ber | slof | slos}
- Router(config-if)# [no] atm sonet-threshold {b1-tca value | b2-tca value | b3-tca value | sd-ber value | sf-ber value}
- Router(config-if)# end
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 |
Router(config)# interface atm slot/ subslot/ port |
Enters interface configuration mode for the indicated port on the specified ATM SPAs. |
Step 2 |
Router(config-if)# atm clock internal |
(Optional) Configures the interface to use its own internal (onboard) clock to clock transmitted data. The default (no atm clock internal ) configures the interface to use the transmit clock signal that is recovered from the receive data stream, allowing the switch to provide the clocking source. |
Step 3 |
Router(config-if)# atm framing {sdh | sonet } |
(Optional) Configures the interface for either SDH or SONET framing. The default is SONET. |
Step 4 |
Router(config-if)# [no ] atm sonet report {all | b1-tca | b2-tca | b3-tca | default | lais | lrdi | pais | plop | pplm | prdi | ptim | puneq | sd-ber | sf-ber | slof | slos} |
(Optional) Enables ATM SONET alarm reporting on the interface. The default is for all reports to be disabled. You can enable an individual alarm, or you can enable all alarms with the all keyword. This command also supports a none [ignore ] option, which cannot be used with any of the other options. See the Configuring AToM VP Cell Mode Relay Support |
Step 5 |
Router(config-if)# [no] atm sonet-threshold {b1-tca value | b2-tca value | b3-tca value | sd-ber value | sf-ber value} Example:
|
(Optional) Configures the BER threshold values on the interface. The value specifies a negative exponent to the power of 10 (10 to the power of minus value ) for the threshold value. The default values are the following:
|
Step 6 |
Router(config-if)# end Example:
|
Exits interface configuration mode and returns to privileged EXEC mode. |
Verifying the SONET and SDH Framing Configuration
To verify the framing configuration, use the show controllers atm command:
Router# show controllers atm 0/2/2
Interface ATM0/2/2 (SPA-3XOC3-ATM-V2[0/2]) is up
Framing mode: SONET OC3 STS-3c
SONET Subblock:
SECTION
LOF = 0 LOS = 1 BIP(B1) = 0
LINE
AIS = 0 RDI = 1 FEBE = 55 BIP(B2) = 0
PATH
AIS = 0 RDI = 1 FEBE = 21 BIP(B3) = 0
LOP = 1 NEWPTR = 0 PSE = 0 NSE = 0
Active Defects: None
Active Alarms: None
Alarm reporting enabled for: SF SLOS SLOF B1-TCA B2-TCA PLOP B3-TCA
ATM framing errors:
HCS (correctable): 0
HCS (uncorrectable): 0
APS
not configured
COAPS = 0 PSBF = 0
State: PSBF_state = False
Rx(K1/K2): 00/00 Tx(K1/K2): 00/00
Rx Synchronization Status S1 = 00
S1S0 = 00, C2 = 13
PATH TRACE BUFFER : STABLE
BER thresholds: SF = 10e-3 SD = 10e-6
TCA thresholds: B1 = 10e-6 B2 = 10e-6 B3 = 10e-6
Clock source: line
Configuring AToM VP Cell Mode Relay Support
To configure Any Transport over MPLS (AToM) Cell Mode Relay, perform the following procedure beginning in global configuration mode:
SUMMARY STEPS
- Router(config)# interface atm slot/ subslot/ port. subinterface multipoint
- Router(config-if)# no ip address ip-address mask
- Router(config-if)# atm pvp vpi l2transport
- Router(config-if)# xconnect peer-ip-address vc-id {encapsulation mpls | pw-class pw-class-name }
- Router(config-if)# end
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 |
Router(config)# interface atm slot/ subslot/ port. subinterface multipoint |
Enters interface configuration mode for the indicated port on the specified ATM SPA |
Step 2 |
Router(config-if)# no ip address ip-address mask |
Removes the IP address that is assigned to this interface (if one has been configured). |
Step 3 |
Router(config-if)# atm pvp vpi l2transport |
Creates a permanent virtual path (PVP) used to multiplex (or bundle) one or more virtual circuits (VCs). |
Step 4 |
Router(config-if)# xconnect peer-ip-address vc-id {encapsulation mpls | pw-class pw-class-name } |
Routes Layer 2 packets over a specified point-to-point VC by using ATM over multiprotocol label switching (AToM). |
Step 5 |
Router(config-if)# end |
Exits interface configuration mode and returns to privileged EXEC mode. |
VP Mode Configuration Guidelines
When configuring ATM Cell Relay over MPLS in VP mode, use the following guidelines:
- You do not need to enter the encapsulation aal0 command in VP mode, but only AAL0 encapsulation is supported with MPLS l2transport.
- One ATM interface can accommodate multiple types of ATM connections. VP cell relay and VC cell relay can coexist on one ATM interface.
- If a VPI is configured for VP cell relay, you cannot configure a PVC using the same VPI.
- VP trunking (mapping multiple VPs to one emulated VC label) is not supported in this release. Each VP is mapped to one emulated VC.
- Each VP is associated with one unique emulated VC ID. The AToM emulated VC type is ATM VP Cell Transport.
- The AToM control word is supported. However, if a peer PE does not support the control word, it is disabled. This negotiation is done by LDP label binding.
- VP mode (and VC mode) drop idle cells.
VP Mode Configuration Example
The following example transports single ATM cells over a virtual path:
Router(config)# pseudowire-class vp-cell-relay
Router(config-pw)# encapsulation mpls
Router(config-pw)# exit
Router(config)# interface atm 1/2/0.1 multipoint
Router(config-if)# atm pvp 1 l2transport
Router(config-if)# xconnect 10.0.0.1 123 pw-class vp-cell-relay
Verifying ATM Cell Relay VP Mode
The following show atm vp command shows that the interface is configured for VP mode cell relay:
Router# show atm vp 1
ATM5/0 VPI: 1, Cell Relay, PeakRate: 149760, CesRate: 0, DataVCs: 1, CesVCs: 0, Status:
ACTIVE
VCD VCI Type InPkts OutPkts AAL/Encap Status
6 3 PVC 0 0 F4 OAM ACTIVE
7 4 PVC 0 0 F4 OAM ACTIVE
TotalInPkts: 0, TotalOutPkts: 0, TotalInFast: 0, TotalOutFast: 0,
TotalBroadcasts: 0 TotalInPktDrops: 0, TotalOutPktDrops: 0
the ATM SPAs on the Cisco ASR 1000 Series Aggregation Services Routers support the following two areas of QoS:
- ATM SPA QoS—QoS on the ATM SPA is implemented in the segmentation and reassembly (SAR) function using the ATM traffic classes (CBR, VBR-nrt, VBR-rt, and UBR) configured with PCR and SCR values.
- Modular QoS CLI (MQC)—Supports per-VC policy maps with class-based weighted fair queueing (CBWFQ), weighted random early detection (WRED), priority, shaping, bandwidth remaining ratio, bandwidth remaining percent, and policing.
Configuring PPPoEoA on ATM SPAs
Beginning in Cisco IOS XE Release 2.5, you can configure PPP over Ethernet (PPPoE) on ATM (PPPoEoA) to connect a network of hosts over a simple bridging-access device to a remote access concentrator. For more information about this feature, refer to the “PPPoE on ATM” feature from the New Features in Cisco IOS XE Release 2.5 at:
http://www.cisco.com/en/US/products/ps9587/products_feature_guides_list.html
For a sample configuration, see the PPPoEoA VC Class and PVC Range Configuration Example.
Saving the Configuration
To save your running configuration to nonvolatile random-access memory (NVRAM), use the following command in privileged EXEC configuration mode:
![]() Note |
To permanently save your configuration changes, you must write them to the nonvolatile RAM (NVRAM) by entering the copy running-config startup-config command in privileged EXEC mode. |
Command |
Purpose |
---|---|
Router# copy running-config startup-config |
Writes the new configuration to NVRAM. |
For more information about managing configuration files, refer to the Cisco IOS XE Configuration Fundamentals Configuration Guide, Release 2, and Cisco IOS Configuration Fundamentals Command Reference publications for your specific software.
Shutting Down and Restarting an Interface on a SPA
Shutting down an interface puts it into the administratively down mode and takes it offline, stopping all traffic that is passing through the interface. Shutting down an interface, though, does not change the interface configuration.
As a general rule, you do not need to shut down an interface if you are removing it and replacing it with the same exact model of SPA in an online insertion and removal (OIR) operation. However, we recommend shutting down an interface whenever you are performing one of the following tasks:
- When you do not need to use the interface in the network.
- Preparing for future testing or troubleshooting.
- Changing the interface configuration in a way that would affect the traffic flow, such as changing the encapsulation.
- Changing the interface cables.
- Removing a SPA that you do not expect to replace.
- Replacing an interface card with a different model of card.
Shutting down the interface in these situations prevents anomalies from occurring when you reinstall the new card or cables. It also reduces the number of error messages and system messages that might otherwise appear.
![]() Note |
If you plan to replace an existing ATM port adapter with an ATM SPA in the Cisco ASR 1000 Series Router and want to use the same configuration, save the slot’s configuration before physically replacing the hardware. This is because all slot configuration is lost when you replace one card type with another card type, even if the two cards are functionally equivalent. You can then re-enter the previous configuration after you have inserted the ATM SPA. |
To shut down an interface, perform the following procedure beginning in global configuration mode:
SUMMARY STEPS
- Router(config)# interface atm slot/ subslot/ port
- Router(config-if)# shutdown
- Router(config-if)# end
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 |
Router(config)# interface atm slot/ subslot/ port |
Enters interface configuration mode for the indicated port on the specified ATM SPA. |
Step 2 |
Router(config-if)# shutdown |
Shuts down the interface. |
Step 3 |
Router(config-if)# end |
Exits interface configuration mode and returns to privileged EXEC mode. |
What to do next
![]() Tip |
When you shut down an interface, the show interface command indicates that the interface is administratively down until the SPA is physically removed from the chassis or until the SPA is re-enabled. |
The following shows a typical example of shutting down an ATM SPA interface:
Router> enable
Router# configure
terminal
Router(config)# interface atm 0/2/2
Router(config-if)# shutdown
Router(config-if)# end
Router# show interface atm 0/2/2
ATM0/2/2 is administratively down, line protocol is down
Hardware is SPA-3XOC3-ATM, address is 000d.2959.d5ca (bia 000d.2959.d5ca)
Internet address is 10.10.10.16/24
MTU 4470 bytes, sub MTU 4470, BW 599040 Kbit, DLY 80 usec,
reliability 255/255, txload 42/255, rxload 1/255
Encapsulation ATM, loopback not set
Encapsulation(s): AAL0
4095 maximum active VCs, 1 current VCCs
VC idle disconnect time: 300 seconds
0 carrier transitions
Last input 01:01:16, output 01:01:16, output hang never
Last clearing of "show interface" counters 01:10:21
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/0 (size/max)
30 second input rate 0 bits/sec, 0 packets/sec
30 second output rate 702176000 bits/sec, 1415679 packets/sec
1000 packets input, 112000 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
2948203354 packets output, 182788653886 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out