Configuring Link Aggregation

Configuring Link Aggregation

Link aggregation combines incoming data from multiple ports into a single high speed link. Configuring the link aggregate channel increases the capacity and availability of the communication channel between a NetScaler and other connected devices. An aggregated link is also referred to as a channel. You can configure the channels manually or by using Link Aggregation Control Protocol

(LACP).

Configuring Link Aggregation Manually

This section describes the procedures to configure a link aggregate channel manually.

Topics include:

• Creating channels

• Binding a channel to a network interface

• Verifying the configuration

Creating Link Aggregate Channels

You can create a channel manually and bind network interfaces to it. The new channel is in the DOWN state until you bind one or more active network interfaces to the channel.

Note: Adding a channel without specifying the network interface number parameter can cause a failover.

Use either of the following procedures to add a channel.

To create a link aggregate channel using the configuration utility

1. In the navigation pane, expand Network and click Channels. The Channels page appears in the details pane.

2. Click Add. The Add Channel dialog box appears.

3. In the Channel ID drop-down list, select the link aggregate ID that you want to add, for example,

LA/1.

4. Click Create and click Close. The link aggregate channel you added appears in the Channels page.

To create a link aggregate channel using the NetScaler command line

At a NetScaler command prompt, type:

add channel LA/1

Binding a Network Interface to a Link Aggregate Channel

When a network interface is bound to a channel, the channel parameters have precedence over the network interface parameters. A network interface can be bound to only one channel.

Note: The state of the channel is UP only when the state of any of the interfaces bound to it is UP.

Binding a network interface to a link aggregate channel changes the VLAN configuration. That is, binding network interfaces to a channel, manually or using LACP, removes them from the VLANs that they originally belonged to and adds them to the default VLAN. However, you can bind the channel back to the old VLAN, or to a new one. For example, if you have bound network interfaces 1/2 and 1/3 to a VLAN with ID 2, and then you bind them to link aggregate channel LA/1, the network interfaces are moved to the default VLAN, but you can bind them to VLAN 2. Use either of the following procedures to bind a network interface to a link aggregate channel.

To bind a link aggregate channel using the configuration utility

1. In the navigation pane, expand Network and click Channels. The Channels page appears in the details pane.

2. Select the channel that you want to bind to a network interface, for example, LA/1.

3. Click Open. The Modify Channel dialog box appears.

4. In the Available Interface list box, select the network interface, for example, 1/8.

5. Click Add. The network interface you selected appears in the Configured Interface list.

6. Click OK.

To bind a link aggregate channel using the NetScaler command line

At a NetScaler command prompt, type:

bind channel LA/1 1/8

Verifying the Configuration

Viewing the channels enables you to troubleshoot any problem in the configuration. You must follow the procedures described in this section to view the configured channels.

Viewing the Properties of Link Aggregate Channels

You can view channel properties such as channel ID, description, uptime, virtual router identification (VRID), and state. Use either of the following procedures to view the properties of the configured channels. The LACP settings appear as a part of the output.

To view the properties of link aggregate channels using the configuration utility

1. In the navigation pane, expand Network and click Channels. The Channels page appears in the details pane. The details of the available channels appear on this page.

2. Verify that the configured channel (LA/1 if you used the example in the previous procedure) appears.

3. Select the configured channel and, in the Details section, and verify that the parameters displayed are correctly configured.

To view the properties of link aggregate channels using the NetScaler command line

At a NetScaler command prompt, type:

show channels

For more information about channels, see the Citrix NetScaler Networking Guide.

Configuring Clock Synchronization

You can configure your NetScaler to synchronize its local clock with a Network Time Protocol (NTP) server. This ensures that its clock has the same date and time settings as the other servers on your network. NTP uses User Datagram Protocol (UDP) port 123 as its transport layer. You have to add NTP servers in the NTP configuration file so that the NetScaler periodically gets updates from these

servers.

To enable clock synchronization on your system

1. Log on to the Citrix NetScaler command line.

2. Change to the shell prompt.

3. Copy the /etc/ntp.conf file to /nsconfig/ntp.conf.

4. Edit /nsconfig/ntp.conf to add the IP address for the desired NTP server under the file’s server and restricting entries.

5. Edit /nsconfig/rc.conf by adding the text ntpd_enable="YES", or, if necessary, create an nsconfig/rc.conf file that includes this text.

6. Reboot the NetScaler to enable clock synchronization.

If you do not have a local NTP server, you can find a list of public, open access, NTP servers at the official NTP site, http://www.ntp.org, under Public Time Servers List. Before configuring your system to use a public NTP server, be sure to read the Rules of Engagement page, (link included on all Public Time Servers pages).

Configuring DNS

You can configure a NetScaler to function as an Authoritative Domain Name Server (ADNS), DNS proxy server, End Resolver, or Forwarder. You can add DNS resource records such as SRV Records, AAAA Records, A Records, MX Records, NS Records, CNAME Records, PTR Records, and SOA Records. Also, the NetScaler can balance the load on external DNS servers.

This section describes the steps you take to configure a NetScaler as a forwarder.

To configure a NetScaler as a forwarder, you need to add external name servers.

Topics include:

• Adding a Name Server (includes an example that you can use in your initial configuration)

• Verifying the Configuration