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Table of Contents

CLAW Packing

Feature Summary

Platforms

Prerequisites

Supported MIBs and RFCs

Configuration Task

Configuration Examples

Command Reference

CLAW Packing

Feature Summary

The Cisco IOS implements the Common Link Access to Workstation (CLAW) channel protocol to transport data between the mainframe and the Cisco CIP in TCP/IP environments. The CLAW packing feature is an enhancement to the CLAW protocol support which enables the transport of multiple IP packets in a single channel operation.

Benefits

The CLAW packing feature significantly increases throughput performance between a mainframe and a Cisco CIP.

Restrictions

Currently, IBM's TCPIP stack does not support the CLAW packing feature. However, the original implementation of the CLAW IP datagram support will continue to work with IBM's stack, even concurrently with the CLAW packing feature.

Platforms

This feature is supported on the following platform:

Prerequisites

The CLAW packing feature requires changes to the mainframe CLAW driver support. In partnership with Cisco Systems, Interlink Computer Science has made the corresponding CLAW driver change to IOS for S/390 Release 2 and Interlink TCPaccess 5.2. Customers must make the necessary changes to their host configurations in order to enable the CLAW packing feature.

Supported MIBs and RFCs

This feature supports the following MIB:

For descriptions of supported MIBs and how to use MIBs, see Cisco's MIB website on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.

No RFCs are supported by this feature.

Configuration Task

To specify CLAW packing, perform the following task in interface configuration mode:

Task Command
Define the CLAW parameters for this device. claw path device-address ip-address host-name device-name packed packed

You must configure the host application and the CIP application names. For guidelines on matching interface configuration values with host system values see the section "Select Host System Parameters" in the "Configuring IBM Channel Attach" chapter of the Cisco IOS Release 11.3 Bridging and IBM Networking Configuration Guide. For more detailed information about configuring or tuning the mainframe TCP IP application, refer to Interlink's TCPAccess 5.2 documentation.

Configuration Examples

The following example configures the IBM channel attach interface to support CLAW packing on HOSTA and HOSTC, and the non-packed version of CLAW on HOSTB:

interface Channel0/0
  ip address 172.18.4.49 255.255.255.248
  no keepalive
  claw C010 F2 172.18.4.50 HOSTA RTRA PACKED PACKED
  claw C020 F4 172.18.4.52 HOSTB RTRA TCPIP TCPIP 
  claw C030 F6 172.18.4.53 HOSTC RTRA PACKED PACKED

The following is an example of a CLAW definition in the host configuration file.

000100 *---------------------------------------------
000200 * Member: IOS390R2.V510.PARM(TCPCFGxx)
000300 * Description: TCP task group configuration 
000400 *---------------------------------------------
000500
000600 * Define the virtual medium
000700
000800 MEDIA VIRTUAL MTU(4096) NAME(LOOPBACK)
000900
001000 * Define the physical medium
001100
001200 MEDIA CLAW    MTU(4096) NAME(ROGCLAW) ASSIST
001300
001400 * Define the host
001500
001600 NETWORK IPADDRESS(172.18.4.50)
001700      SUBNET(255.255.255.248)
001800
001900 *
002000
002100 CLAW DEVADDR(8f2)
002200      BUFSIZE(32768)
002300      IBUF(5)
002400      OBUF(5)
002500      RESTART(60)
002600      HOSTNAME(HOSTA)
002700      WSNAME(RTRA)
002800      START
002900      PACKED
003000
003100 * Define gateway
003200
003300 ROUTE DEST(0.0.0.0) ROUTE(172.18.4.49)
003400
003500 * Define the transport pr
003600
003700 TCP  MAXRCVBUF(131072)
003800      MAXSNDBUF(131072)
003900      DEFRCVBUF(131072)
004000      DEFSNDBUF(131072)
004100      DELAYACK(2)
004200      FASTRX(3)
004300      MAXRXMIT(18)
004400      MINDEV(90)
004500      PORTUSE(1:4095)
004600      PORTASGN(4096:8191)
004700
004800 UDP  MAXRCVBUF(64000)005200      PORTUS
004900      MAXSNDBUF(64000)
005000      DEFRCVBUF(64000)
005100      DEFSNDBUF(64000)005300      PORTAS
005200      PORTUSE(1:4095)
005300      PORTASGN(4096:8191)
005400
005500 RAW  MAXRCV
005600      MAXSND
005700

Command Reference

This section documents new or modified commands. All other commands used with this feature are documented in the Cisco IOS Release 11.2 command references.

claw

Use the claw interface configuration command to establish the IBM channel attach configuration for an ESCON Channel Adapter (ECA) interface or bus-and-tag Parallel Channel Adapter (PCA) interface on the Cisco 7000 with RSP7000 and Cisco 7500 series.

claw path device-address ip-address host-name device-name host-app device-app [broadcast] [backup]
no claw
path device-address
Syntax Description
path Hexadecimal value in the range 0x0000 to 0xFFFF. This value specifies the data path and consists of two digits for the physical connection (either on the host or on the ESCON director switch); one digit for the control unit logical address, and one digit for the channel logical address. If not specified in the IOCP, the control unit logical address and channel logical address default to 0.
device-address Hexadecimal value in the range 0x00 to 0xFE. This is the unit address associated with the control unit number and path as specified in the host IOCP file. The device address must have an even value.
ip-address IP address specified in the HOME statement of the host TCP/IP application configuration file.
host-name Host name specified in the device statement in the host TCP/IP application configuration file.
device-name CLAW workstation name specified in the device statement in the host TCP/IP application configuration file.
host-app Host application name as specified in the host application file. If connected to the IBM TCP host offerings, or if the CLAW packing feature is not enabled on the mainframe TCPIP stack, this value will be tcpip, which is the constant specified in the host TCP/IP application file. When attached to other applications, this value must match the value hard coded in the host application.

To enable the CLAW packing feature, specify this value as packed.

device-app CLAW workstation application specified in the host TCPIP application. If connected to the IBM TCP host offerings, or if the CLAW packing feature is not enabled on the mainframe TCPIP stack, this value will be tcpip, which is the constant specified in the host TCP/IP application file. When attached to other applications, this value must match the value hard coded in the host application.

To enable the CLAW packing feature, specify this value as packed.

broadcast (Optional) Enables broadcast processing for this subchannel.
backup (Optional) Enables this CLAW connection to be used as part of a backup group of CLAW connections for the specified IP address.
Default

This command has no defaults.

Command Mode

Interface configuration

Usage Guideline

This command first appeared in Cisco IOS Release 10.3.

This command defines information that is specific to the hardware interface and the IBM channels supported on the interface.

CLAW devices are used to switch IP packets between a mainframe and a channel attached router.

At most, 128 statements can be configured per interface because each port adapter is limited to
256 subchannels. Each CLAW device uses a read channel and a write channel. There is also a restriction of 64 unique paths.

Duplicate IP addresses are invalid for non-backup configurations.

Duplicate IP addresses are permitted if they appear within a backup group of only claw or offload interface configuration commands. All configuration commands in one backup group must specify the backup keyword.

You can use the path interface configuration command to specify a number of paths that belong to a backup group. In that case, a claw IP host backup configuration command is used that needs no path variable or backup keyword.

The CLAW packing feature is supported on the Cisco 7500 series routers.

Example

The following example shows how to enable IBM channel attach routing on the CIP port 0, which is supporting an ESCON direct connection to the mainframe channel:

interface channel 3/0
ip address 172.18.4.49 255.255.255.248
claw c020 F4 172.18.4.52 HOSTB RTRA TCPIP TCPIP

The following example shows how to enable CLAW packing:

interface Channel 3/0
ip address 172.18.4.49 255.255.255.248
claw c010 F2 172.18.4.50 HOSTA RTRA PACKED PACKED
Related Commands

show extended channel packing names

show extended channel packing stats

show extended channel packing names

Use the show extended channel packing names privileged EXEC command to display CLAW packing statistics.

show extended channel slot/port packing names [path [device-address]]
Syntax Description
slot Slot number.
port Port number.
path (Optional) Hexadecimal value in the range 0x0000 to 0xFFFF. This specifies the data path and consists of two digits for the physical connection (either on the host or on the ESCON Director switch): one digit for the control unit address, and one digit for the channel logical address. If not specified, the control unit address and channel logical address default to 0.
device-address (Optional) Hexadecimal value in the range 0x00 to 0xFE. This value is the unit address associated with the control unit number and path as specified in the host IOCP file. For CLAW and offload support, the device address must have an even value.
Default

The data path default for the control unit address and the channel logical address is 0.

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.2BC.

Sample Display

The following is sample output from the show extended channel packing names command:

router# show extended channel 3/0 packing names
Path: C010  Devices: F2,F3 CLAW Link: 1 
    Sublink            Link Names
       0                 CONTROL
       1              IP        IP      
       2              CKSUM     CKSUM   
Path: C030  Devices: F6,F7 CLAW Link: N 
    Sublink            Link Names
  DISCONNECTED           CONTROL
  DISCONNECTED        IP        IP      
  DISCONNECTED        CKSUM     CKSUM   

Table 7 describes the fields shown in the display.


Table 7: Show Extended Channel Packing Names Field Descriptions
Field Description
Path The path from the CLAW, offload, or CSNA configuration. It indicates which port on the switch is used by the channel side of the configuration.
Devices The device address for each device. One CLAW connection requires 2 devices. You need only specify the even address.
CLAW Link The established CLAW link number used for all CLAW packing messages. A number value indicates that a CONTROL sublink is connected. "N" indicates that a control sublink is disconnected.
Sublink

  • DISCONNECTED indicates that a sublink connection for a particular link name is not established.

  • 0 indicates that the CONTROL sublink is established.

  • 1 - 15 indicates the negotiated sublink number for each application pair.

Link Names

The name used to represent the type of traffic that flows over a particular sublink.

  • CONTROL indicates the sublink used to transport CLAW packing control messages.

  • IP indicates the sublink used to transmit IP datagrams whose TCP checksum is handled by the host.

CKSUM indicates the sublink used to transmit IP datagrams that use the CMCC checksum assist feature.

show extended channel packing stats

Use the show extended channel packing stats privileged EXEC command to display CLAW packing statistics.

show extended channel slot/port packing stats [path [device-address]]
Syntax Description
slot Slot number.
port Port number.
path (Optional) Hexadecimal value in the range 0x0000 to 0xFFFF. This specifies the data path and consists of two digits for the physical connection (either on the host or on the ESCON Director switch): one digit for the control unit address, and one digit for the channel logical address. If not specified, the control unit address and channel logical address default to 0.
device-address (Optional) Hexadecimal value in the range 0x00 to 0xFE. This value is the unit address associated with the control unit number and path as specified in the host IOCP file. For CLAW and offload support, the device address must have an even value.
Default

The data path default for the control unit address and the channel logical address is 0.

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 10.3.

Sample Display

The following is sample output from the show extended channel packing stats command:

router# show extended channel 3/0 packing stats
Path: C010 Devs: F2,F3 CLAW Link: 1  Read Blks: 4584       Wrt Blks: 15054     
                  Packets               Bytes                Drops
Linkname       Read      Write      Read     Write       Read      Write   Err C
CONTROL           4          2       128        64          0          0     0 Y
IP                5          5       500       500          0          0     0 Y
CKSUM          4694      93584    187854  53889648          0          0     0 Y
  Total:       4703      93591    188482  53890212          0          0     0
Path: C030 Devs: F6,F7 CLAW Link: N  Read Blks: UNKNOWN    Wrt Blks: UNKNOWN   
                  Packets               Bytes                Drops
Linkname       Read      Write      Read     Write       Read      Write   Err C
CONTROL           0          0         0         0          0          0     0 N
IP                0          0         0         0          0          0     0 N
CKSUM             0          0         0         0          0          0     0 N
  Total:          0          0         0         0          0          0     0

Table 8 describes the fields shown in the display.


Table 8: Show Extended Channel Packing Stats Field Descriptions
Field Description
Path The path from the CLAW, offload, or CSNA configuration. It tells which port on the switch is used by the channel side of the configuration.
Devs The device address for each device. One CLAW connection requires 2 devices. You need only specify the even address.
CLAW Link The established CLAW link number used for all CLAW packing messages. A number value indicates that a CONTROL sublink is connected. "N" indicates that a control sublink is disconnected.
Read Blks The number of CLAW channel blocks read.
Write Blks The number of CLAW channel blocks written.
Linkname The name used to represent the type of traffic that flows over a particular sublink.

  • CONTROL indicates the sublink used to transport CLAW packing control messages.

  • IP indicates the sublink used to transmit IP datagrams whose TCP checksum is handled by the host.

CKSUM indicates the sublink used to transmit IP datagrams that use the CMCC checksum assist feature.

Packets
Read   Write
The total number of packets read and written for each sublink.
Bytes
Read   Write
The total number of bytes read and written for each sublink.
Drops
Read   Write
The total number of dropped read and write packets for each sublink.
Err The number of errors. Each error produces an error message at the router console.
C Connection state of a sublink. 'Y' indicates connected. 'N' indicates not connected.
Total The total for each of the recorded statistics.

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