Release Notes : BIG-IP Link Controller Release Note, version 4.3

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Link Controller

  • 4.3.0
Release Notes
Original Publication Date: 04/26/2002 Updated Date: 04/18/2019


This release note documents version 4.3 of the BIG-IP Link Controller software.  This release supports the BIG-IP 2000 platform.


Minimum system requirements

This release is supported only on the BIG-IP 2000 platform.

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Installing the software

This procedure describes how to install the Link Controller software on the BIG-IP 2000. Typically, the software is pre-installed and this procedure is not required.

This procedure describes how to boot the BIG-IP from a CD that is mounted on a remote host, as a way to perform a full installation onto the BIG-IP hardware.

To perform a network boot, you must complete the following tasks:

Designate a remote host to be a Pre-boot Execution Environment (PXE) server

The first task in performing a network boot is to select a remote host to function as a Pre-boot Execution Environment (PXE) server.  This host can be any machine that has a CD-ROM drive, supports booting from the CD ROM, and resides on the same network as the BIG-IP client. Note that the PXE server must be connected to the Mgmt (3.1) port on the IP Application Switch.

Boot the remote host from the CD

The second task is to insert the CD into the drive on the remote host and reboot the system from the CD-ROM drive in the normal manner for that host.

Configure the remote host as a Pre-boot Execution Environment (PXE) server host

When you boot from the CD, the remote host displays the following prompt:

    Select installation option:
    1 Install software onto hard disk
    2 Setup server to provide network installation
    Enter choice [1]?

  1. Select 2, Set up server to provide network installation.
    A list of available network interfaces on the machine appears.  You are prompted to select one for the PXE server interface.

  2. Select the interface to be used as the server interface. This produces the prompt: Use existing DHCP server on subnet [no]?

    • If there is an existing DHCP server on your subnet and you want to use this DHCP server to avoid possible conflicts, type yes, and the server configuration is automatically completed.

    • If you want to set up this server as the DHCP server, choose the default, no. This produces the following series of prompts.

      IP network [10.1.10]?
      IP address of server  10.1.10[n] [199]?
      Lower range for clients 10.1.10.[n] [199]?
      Upper range for clients 10.1.10.[n] [200]?

  3. If your subnet consists of the server and the target Link Controller only, or is otherwise a private subnet, use the default IP addresses provided.  If the subnet is shared by other machines and there is a possibility of conflict, substitute the appropriate unique addresses and ranges.  When you are done, the settings you have entered are displayed and you are asked to accept or reject them.

  4. If the settings displayed are correct, enter yes. If they are not, enter no and the prompts are repeated.  When you have accepted your settings, the server configuration is complete.

Boot the client from the remote Pre-boot Execution Environment (PXE) server

You are now ready to perform the network boot at the client console.

  1. Boot the IP Application Switch as follows:
    • If the machine is powered down, power it up, and within the first ten seconds actuate the NETboot switch on the front panel using a paper clip.

    • If the machine is already booted, type the following two commands:

      bigpipe global net_reboot enable

    The machine now attempts to discover the PXE host. When it does, the following timed message appears on the screen.
    Press F8 or Control-space to view menu...

  2. Press F8 or Control-space before the prompt times out. (If it times out, the choice defaults to BIG-IP Install.)  The following menu of options appears if you press F8 or Control-space:

    BIG-IP Install
    Local Boot

  3. If you want to perform a Link Controller installation, select BIG-IP Install.
    The client creates and mounts an image of the Link Controller install CD, and initiates the installation process, returning the following prompt:

    Select installation option:
    1 Install software onto hard disk
    2 Setup server to provide network installation
    Enter choice [1]?

  4. Type 1 to select the Install software onto hard disk option. From this point on, the process is identical to that using a local CD. Follow the prompts for installing the software from the CD.

  5. If you want to boot from your local hard drive, select Local Boot.
    The machine boots from its hard drive.

  6. If you want to run DOS for the purpose of flashing the BIOS, select DOS.
    The machine boots as a DOS platform and returns a DOS prompt.

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New features and enhancements

This section describes new features and enhancements included in this release of the Link Controller software.

Link load balancing enhancements

This release includes the following link management enhancements:

Link Performance features
With the BIG-IP Link Controller, you can configure multiple Internet connections for Internet/network high availability. You can also increase the bandwidth to and from your network by adding additional links.

  • Link Capacity load balancing
    The Link Capacity load balancing method uses the link capacity and limit threshold you define for each link. You can define the link capacity and threshold when you create a link object. You can set independent thresholds for inbound, outbound, and concurrent traffic.

  • Network Proximity load balancing
    This load balancing method uses the round trip time, completion rate, and number of router hops to calculate which link is best for inbound traffic.

  • Static link load balancing options
    There are three primary static link load balancing options available in the Link Controller. The first one, Global Availability, allows you to direct all traffic down a primary link. The traffic is shifted to another link if the main link fails. The second static option is Round Robin. Round Robin allows you to distribute traffic evenly across your links. If a link fails, the Link Controller shifts traffic to the other links in the load balancing pool. The third static method is Ratio. Ratio allows you to send a defined percentage of traffic through a particular link. For example, you might want to send a larger portion of the traffic down a T3 link than down a DSL connection.

Link Cost analysis features
These features allow you to configure cost values associated with each ISP link you have to the Internet. You can set cost limits for links, limit bandwidth usage, and control incoming and outgoing traffic based on the dynamic bandwidth costs of sending traffic over a link.

  • Link Cost load balancing
    The Link Cost load balancing method uses the costs you define for a link. You define the link costs when you create a link object. This load balancing method sends traffic through the most economical link before sending traffic over a more costly connection.

  • Variable Cost link load balancing
    The Variable Cost link load balancing method provides the ability to define pricing tiers for a link, depending on bandwidth usage. For example, you might have a link that costs $1000 per Mbps for the 0 to 3 Mbps range, and $1400 per Mbps for the 3 to 6 Mbps range. The Link Controller factors the costs into the Quality of Service scores, which is an integral element in the Dynamic Ratio load balancing algorithm. The Link Controller then distributes traffic to the link with the best overall score, resulting in lower costs and more efficient bandwidth usage.

For more information on the link load balancing and link cost features, see the online help for the Modify Links screen. To view the Modify Links screen, click Links on the navigation pane, and then click a link name in the link list. To view detailed information about a screen, click Help on the toolbar.

Monitoring links and viewing link statistics

  • Transparent monitoring
    You can monitor the routers for your links using transparent monitoring. Transparent monitoring ensures that you are alerted to traffic anomalies on the router so that you can direct traffic to functional links.

  • Internet Link Evaluator
    The Internet Link Evaluator shows the average round trip times, completion rates, and router hops over the links managed by the Link Controller and the local DNS servers on any of the seven continents. You can use the Internet Link Evaluator to determine which links best serve users in a particular global region. You can also use the Internet Link Evaluator to compare link performance to a particular global region.

    To view the Internet Link Evaluator, on the navigation pane, click Link Statistics, and then click Link Evaluator. The Internet Link Evaluator screen opens, where you can view average round trip times, completion rates, and router hops for your links.

  • Link Statistics screen
    The Link Statistics screen provides a summary of status, current traffic and limits, and costs for your links.

    To view the Link Statistics screen, on the navigation pane, click Link Statistics, and then click Links. The Link Statistics screen opens, where you can view a real-time analysis of your links.

  • Configuration Checker
    The Configuration Checker evaluates your Link Controller configuration and lists any errors or warnings that may exist. Use the Configuration Checker to verify that you have correctly configured the Link Controller for inbound and outbound link load balancing.

    To view the Configuration Checker, on the navigation pane, click Link Statistics, and then click Config Checker. The Configuration Checker screen opens, where you can view an analysis of your configuration.

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Configuring and using the new software

This section provides information about both required and optional configuration changes.

Required configuration changes

The current release has no required configuration changes.

Optional configuration changes

For details on configuring and using the software, refer to the BIG-IP Link Controller Solutions Guide. For details in the specific components of the Link Controller, refer to the BIG-IP Link Controller Reference Guide. Both of these documents are available on the Welcome screen in the Configuration utility.

Wildcard forwarding virtual server

If you are currently using IP forwarding, for BIG-IP version 4.0 and higher we strongly recommend that you use a wildcard forwarding virtual server instead of or in addition to IP forwarding. With the additional features in BIG-IP 4.x, using a wildcard forwarding virtual server is faster than using IP forwarding. A wildcard forwarding virtual server also allows you to get statistics on the exact amount of traffic flowing through the system.

If you want to configure a wildcard forwarding virtual server to handle IP forwarded traffic, use the following procedure on your 4.x system. You can perform this procedure on-the-fly without causing any interruption of service.

  1. To set up timeouts type the following commands:

  2. bigpipe service 0 tcp enable
    bigpipe service 0 timeout tcp 30
    bigpipe service 0 udp enable
    bigpipe service 0 timeout udp 30

  3. Set up a wildcard forwarding virtual server by typing the following command:

  4. bigpipe virtual forward

  5. If you want to allow protocols other than TCP and UDP through the forwarding virtual server, use the following command. The default timeout is 15 seconds.
    bigpipe virtual any_ip enable
    If you want to change the default timeout for this setting, use this syntax:
    bigpipe virtual any_ip timeout <seconds>
    For example, if you want to change the default timeout to 5 seconds, type this command:
    bigpipe virtual any_ip timeout 5

  6. To save your new configuration, type:

  7. bigpipe save

For more information on wildcard forwarding virtual servers, see the BIG-IP Administrator Guide.

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Known issues

The following items are known issues in the current release.

Port mirroring on the IP Application Switch  (CR18435)
Ports not configured in a VLAN are not mirrored on the IP Application Switch platform.

proxy_arp does not fail over on VLAN group  (CR18928)
When the BIG-IP goes from active to standby and MAC masquerading is not configured, layer 2 forwarding VLAN groups continue to forward packets until the packet’s source ARP cache times out.

Sequence number tracking  (CR19392)
Out of order packets to a delayed binding virtual server may cause synchronization errors in sequence number tracking.

TCP 4-way close detection  (CR19591)
When an upstream device drops packets, or sends packets out of order, TCP 4-way close may not be properly detected.

Syslog pinger requires changes for increased resilience  (CR19874)
If you define, delete, and then redefine a monitor, without deleting the changes in the /etc/syslog.conf file, the monitor may not function properly.

Error message on Modify Wide IP screen is benign  (CR20204)
You may see an error message (# 331845) on the Modify Wide IP screen. This message is benign.

Unique self IP addresses with different masks are seen as being on the same network  (CR20378)
The Link Controller does not support supernetting. You cannot define two networks on the Link Controller where one of the networks includes the other.

Viewing link statistics and internal system traffic  (CR20689)
When you review the Link Statistics screen in the Configuration utility, the data transfer rates do not include internal system traffic.

Upgrading the software and the /etc/hosts.allow file  (CR20715)
When you upgrade the BIG-IP Link Controller version 4.3 software, and you use the im --force <filename>.im command, the /etc/hosts.allow file is deleted. You can resolve this issue by adding the following line to the /etc/hosts.allow file after you perform the upgrade:
big3d : ALL.

Values for Link Limits  (CR20744)
When you type values for bandwidth limits, on the Modify Link screen in the Configuration utility, and you type a number that is not divisible by 8, the Configuration utility rounds the value to the next lowest number that is divisible by 8.

SNMP and link statistics  (CR20849)
When you switch from internal statistics to SNMP gathered statistics the metrics display a 10 second long Mbps incongruity. This may result in very large rate values. This data value may take some time to flush out of the history averages. However, it will only effect the load-balancing algorithm for one 10 second period.

Redundant system failover behavior  (CR20851)
If you synchronize the Link Controller configuration from the standby unit to the active unit, failover occurs, and the standby unit becomes active. If you synchronize the Link Controller configuration from the active unit to the standby unit, no failover occurs.

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