Cisco Catalyst 8500 Series Multiservice Switch Routers

This document provides a list of frequently asked questions on the ATM Router Module (ARM) module.

A. Yes, ARM supports Integrated Routing and Bridging (IRB). This provides a means to route a given protocol between routed and bridged interfaces. Bridged Virtual Interfaces (BVIs) configured with IRB can be used to route a protocol between bridge groups.

A. The original ARM (ARM I) does not support traffic shaping. It only supports unspecified bit rate (UBR). The ARM for 8510 MSR supports variable bit rate (VBR). The enhanced ARM (ARM II) only supports constant bit rate (CBR) traffic shaping which starts with Cisco IOS® Software Release 12.1(7a)EY. ARM does not support traffic shaping by itself. Shaping is achieved by configuring a Shaped or Hierarchical VP Tunnel (HVPT) on the ATM interface and directing the traffic from ARM through the tunnel. Once the tunnel is configured, all the service classes are supported. Traffic shaping is supported in the hardware with the help of a Traffic-Shaping Carrier Access Module (TSCAM) on the Catalyst 8510 MSR and LS1010.

A. ARM I is C8510-ARM-64K or C8540-ARM-64K

ARM II is C8510-ARM2 or C8540-ARM2

A. These hardware restrictions apply to the Catalyst 8540 MSR, Catalyst 8510 MSR, and LS1010 ARMs, and the ARM II on Catalyst 8540 MSR:

• The ARM is installed in any slot except a route processor slot. In Catalyst 8540 MSR, it is installed in a switch processor slot.
• The ARM is only supported on LS1010 ATM switches with a multiservice ATM switch route processor with Feature Card Per Flow Queuing (FC-PFQ), and the Catalyst 8510 MSR system software image. On LS1010 switches, ARM is supported only with FC-PFQ ATM Switch Processor (ASP-C).
• The ARM does not operate with FC-PCQ on the processor card. FC-PCQ provides a subset of the ATM Forum traffic management features provided by FC-PFQ.
• You can install up to two ARMs per chassis on 8540MSR in slot 0-3 and 9-13 (either two ARM II or a combination of ARM I and II).
• A maximum of one ARM is installed on 8510MSR and LS1010.
• When you hot swap an ARM, wait for one minute after you remove the module before you insert a new module.
• The ARM is only supported on ATM switches which have a multiservice ATM switch processor installed.

A. LAN Emulation (LANE) needs Cisco IOS Software Release 12.0(4a)W5(11a) or later. Request for Comments (RFC) 1483 needs Cisco IOS Software Release 12.0(10)W5(18) or later. For ARM II, the minimum Cisco IOS Software Release is 12.1(5)EY.

A. There are some Cisco IOS software restrictions that apply to ARM in the Catalyst 8500 MSR Series. They are listed here:

• Use tag switching functionality with caution. Do not distribute routes learned through tag switching to Fast Ethernet or Gigabit Ethernet, or the other way around. Otherwise, the route destinations might be unreachable.
• The ARM does not initialize if it replaces an ATM port adapter or interface module when Hierarchical VP Tunnels (HVPTs) are globally enabled. Reboot the switch to initialize the ARM.
• ATM Director does not support any permanent virtual circuit (PVC) commands.
• Only LAN Emulation Clients (LECs) or Request for Comments (RFC) 1483, not both, can be configured on an ARM interface.
• RFC 1483 on the ARM supports only ATM adaptation layer 5 (AAL5) Subnetwork Access Protocol (SNAP) encapsulation.
• Even though each ARM interface supports a maximum of 2048 virtual circuits (VCs), only 1400 to 1500 external VCS are configured. Internal VCS use up the rest.
• IP multicast is only supported over 1483 LLC/SNAP encapsulated PVCs.
• You can have a maximum of 64 LECs per chassis.
• Do not install an ARM in a slot pair where HVPTs are configured. Slot pairs 0 and 1, 2 and 3, 9 and 10, and 11 and 12 use the same switching modules for scheduling. For example, do not install an ARM in slot 10 when HVPTs are configured on the slot. HVPT and ARM cannot co-exist on LS1010/8510 MSR.

A. Configuring bridging on ARM is done in the same way as the Cisco router platforms. Only the bridge-group number at the interface and the bridge protocol in global configuration need to be specified. A sample of this is shown in this output:

Switch(config)# interface atm 3/0/0
Switch(config-if)# atm PVC 2 200 interface atm 1/0/0 0 200

!---  The virtual path identifier (VPI) number on the ARM interface must be "2."

Switch(config-if)# bridge-group 5
Switch(config-if)# end
Switch(config)# interface fastethernet 0/0/0
Switch(config-if)# no cdp enable
Switch(config-if)# bridge-group 5
Switch(config-if)# end
Switch(config)# bridge 5 protocol ieee

A. These are some of the most useful show commands used to troubleshoot ARM. However, these two issues must be taken care of:

1. Use regular LAN Emulation (LANE), Request for Comments (RFC) 1483, and RFC 1577 debugging techniques and commands.
2. Verify different flags in the if-entry for that interface/sub-interface of the ARM port.

Issue the show epc if-entry interface atm command. Test the Content-Addressable Memory (CAM) information between the egress Gigabit Ethernet interface and the ingress ATM interface.

Check for the information shown in this example :

• The Broute VC field status is "up."
• Notice the Broute VC number. In the example, the Broute VC is "322."
• IP routing is "on."

  Switch# show epc if-entry interface atm 10/0/0 entry gigabitEthernet 3/0/1
  IF Entry for GigabitEthernet3/0/1 on atm10/0/0 
     Mac(hex) - 00:90:21:41:88:38 
     isMyInteface : False isSubInterface : False< 
     Status Up Broute VC - 322 Bcast VC - 0 
     Netmask: 24< 
     FEC disabled 
     Trunking Disabled 
     State : Not-Applicable/Listening/Blocking 
     IP routing on bridging off 
     IPX routing off bridging off 
     Appletalk routing off 
     In Encapsulation: 
     ICMP Redirect enabled Unreachable enabled

• Verify the CAM entries for that IP address/network. Issue the show epc ip-address command with the IP address of the egress interface to display the status of the Media Access Control (MAC) address rewrite and the virtual channel identifier (VCI) number, as shown in this example:

  Switch# show epc ip-address interface atm 10/0/0 128.250.0.1
  IPaddr: 128.250.0.1 MACaddr: 0000.0c07.ac01  Routed to VC(940)
  
  !--- Check the Routed to VC field (in this example, the VC is "940").
  
  
  !--- The value is used in the next step.
  
  

• Issue the show atm vc traffic interface atm command with the virtual path identifier (VPI) and VCI parameters to see the receive (RX) and transmit (TX) cell counts. Check the RX and TX counters on the VC. Verify if the traffic flows through. This example shows this situation:

  Switch# show atm vc traffic interface atm 10/0/0 0 940
  Interface         VPI  VCI   Type      rx-cell-cnts     tx-cell-cnts
  atm10/0/0          0    940   SVC      18               25
  

• Issue the show atm vc traffic interface atm command with the VPI and VCI parameters, to confirm that the receive and transmit cell counts are incrementing, as shown in this example:

  Switch# show atm vc traffic interface atm 10/0/0 0 940
  Interface         VPI  VCI   Type      rx-cell-cnts     tx-cell-cn
  TM10/0/0           0   940   SVC       33               40

• Verify that the rx-cell-cnts and tx-cell-cnts fields on all eight channels are incrementing (from 128/34 up to VPI 135/34), as shown in this example:

  Switch# show atm vc traffic int a12/0/0 128 34
  Interface         VPI  VCI   Type      rx-cell-cnts     tx-cell-cnts
  atm12/0/0         128  34    PVC       2521             6961
  
  ar02_m84_01# show atm vc traffic int a12/0/0 128 34
  Interface         VPI  VCI   Type      rx-cell-cnts     tx-cell-cnts
  atm12/0/0         128  34    PVC       2530             6979
  .
  .
  ar02_m84_01# show atm vc traffic int a12/0/0 135 34
  Interface         VPI  VCI   Type      rx-cell-cnts     tx-cell-cnts
  atm12/0/0         135  34    PVC       2691             5382    
  
  ar02_m84_01# show atm vc traffic int a12/0/0 135 34
  Interface         VPI  VCI   Type      rx-cell-cnts     tx-cell-cnts 
  atm12/0/0         135  34    PVC       2697             5394