Network Products
Updated: 17 April 1997
 

IP Switching Tech Tips


Setting the Default VCI for IP Switching


Introduction

ATM based networking protocols use a series of low numbered VCIs, or Virtual Channel Identifiers, to do various dedicated tasks such as signaling, and flow control. Ipsilon originally designated VCI 15 for IFMP. Other users of VCI 15 include Digital, who uses it for FLOWmaster, and FORE systems who uses it for their proprietary SPANS protocol.

Digital provides a means of solving potential interoperability problems by enabling the network administrator to designate the VCI for IFMP at the Switch, the Gateway, and the end station. This tech tip details the steps necessary to set the IFMP VCI to a value that works for your particular installation. Digital recommends the use of VCI 32 for IFMP.

Once you designate a VCI for IFMP, each device that participates in IP Switching needs to use the same VCI. You must ensure that every Controller, Gateway, GIGAswitch/ATM, and ATM adapter, that is participating directly in IP Switching, use the same VCI for IFMP. If you do not do this, IP Switching simply will not work.

Setting the IFMP VCI on the GIGAswitch/ATM

All aspects of IP Switching configuration for the GIGAswitch/ATM are handled using the command configure_ipswitch. This procedure shows how to use this command to set the IFMP VCI for the GIGAswitch/ATM.

  1. Activate the GIGAswitch console using either a directly connected terminal, or a TELNET connection.
  2. From the Clock Card Console prompt, issue a ^O to enter Line Card Forwarding mode. Look for the GIGAswitch/ATM-> prompt to indicate that you have entered line card forwarding mode.
  3. Enter the configure_ipswitch command to start the IP switching configuration process.
  4. The first question you are asked is the default VCI that you wish to use for IFMP. To accept the current value shown, press return. To change it, enter a new value.
  5. The second question concerns the port that connects the GIGAswitch to the IP Switch Controller. This triplet of numbers identifies the slot number and port number where the controller link is attached to the GIGAswitch. The third number identifies the VCI over which the IP Switch Controller communicates with the GIGAswitch using GSMP. Although not an explicit requirement, the value entered here for this VCI should be the same as the IFMP VCI entered in the previous step.
  6. Press return to accept the default values for the remaining IP Switching options.
  7. When asked to save the new configuration, select 1 for save, if you wish to save your changes, or 2 to discard them.
The changes you have made take effect after you reboot the GIGAswitch.

Setting the IFMP VCI on the IP Switch Controller and Gateway

To set the IFMP VCI on the IP Switch Controller and Gateway, use the following procedure:
  1. Attach a VT compatible terminal, or PC running a terminal emulator, to the console port of the machine.
  2. Log into the root account on the machine. The root account has unrestricted system privilege, so move cautiously when logged into the root account, as your ability to render the system unusable is unlimited.
  3. Use vi to edit the file /etc/rc.local
  4. Add the following line to the bottom of the file, or simply modify it if it is there already:

    /usr/ips/change_llc ips0 32

    The 32 in the above example is the designated VCI for IFMP. Replace the 32 with the VCI you have designated for your site.

Save the file, and exit the editor. Issue the command reboot from the command prompt to reboot the system.

This procedure needs to take place on the controller, and all gateways that will be working together.

Setting the IFMP VCI on the ATMworks350 under NT

To set the IFMP VCI for an ATMworks350 running under Windows NT, use the following procedure:

  1. Apply power to your system, and boot the Windows NT operating system. Version 3.51 or greater is required.
  2. Log in to the administrator account, or other such account that has administrator privilege.
  3. NOTE: To set the IFMP VC, you need to alter the contents of the Windows NT registry database. This is can be a complex and error prone task. Care must be taken when modifying the registry, as indiscriminately changing values in the registry can render the system inoperable.
  4. Start the registry editor application regedt32 either from the start menu or from a command prompt.
  5. Expand the tree of registry keys under hkey_local_machine\system\CurrentControlSet\services and look for entries of the form dglpb* where the star may be any number from 1 to 9.
  6. Each dglpb entry represents an ATMworks350 adapter. Identify those that you wish to have working in the IP Switching environment. For each of the adapters you identify, do the following.
  7. Expand the dglpb tree, and under the parameters key, add the value IpsilonSNAPVCI. The entry must follow exactly this case and spelling.
  8. Associate with this value entry the new value you wish to use for the IFMP VC.
  9. When you have completed updating all of your adapters, exit the registry editor and restart the system.