FAQ: The "trunk" or "tagall" Option of NetScaler Appliance

FAQ: The "trunk" or "tagall" Option of NetScaler Appliance

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Article ID: CTX115575

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Description

Q: What is the "trunk" or "tagall" option on a NetScaler interface used for?

A: NetScaler software release earlier than version 9.2 referred to the tagall option as trunk.

Different network equipment vendors use the term tagall differently. Some use it to describe a switch port on which you can define more than one Virtual Local Area Network (VLAN) in compliance to the Institute of Electrical and Electronics Engineers (IEEE) 802.1q guidelines. Other vendors use this term to describe a bandwidth-aggregating port, such as Link Aggregation Control Protocol (LACP). In NetScaler appliance, tagall option previously called the trunk option, mainly relates to tagging the VLAN traffic through interfaces.

When you enable the tagall option on a NetScaler interface, all the VLAN traffic on that interface, including that of the Native VLAN (VLAN1), is tagged. This is necessary because some switch vendors tag all VLANs when the trunk option is enabled on these switches.

You must disable the tagall option on the NetScaler appliance, if you do not want all the VLAN traffic through a particular interface to be tagged. Additionally, a VLAN can be bound to an interface and tagged individually.

Examples

Tags all the VLANs going out of the interface 1/1 including the native VLAN:
set interface 1/1 -tagall ON

None of the VLANs are tagged through the interface 1/1 but with an exception:
add vlan 3
add vlan 4
set interface 1/1 -tagall OFF

VLANs 3 and 4 are tagged through the interface 1/1 even if the –tagall option is OFF:
bind vlan 3 -ifnum 1/1 –tagged
bind vlan 4 –ifnum 1/1 –tagged

The preceding commands configures the NetScaler appliance to receive the VLAN frames on VLAN 3 and 4 through interfaces with IEEE 802.1q tags.

The NetScaler appliance uses the native VLAN for the high availability traffic, which includes the heartbeats packets, synchronization, and command propagation. Therefore, you must ensure that the native VLAN has connectivity through all connected interfaces. By default, the native VLAN, VLAN1, is bound to an interface if you do not explicitly bind the interface to a VLAN.

If the tagall option is enabled on the NetScaler appliance, and the connecting switch does not allow or tag frames on the native VLAN, then there might be issues arising with high availability communication. This situation can lead to major problems with the high availability functionality. The following are some of the probable issues that can result from this situation:

  • The configuration synchronization failures between the high availability nodes.
  • Missing heartbeat packets leading to failovers.
  • Split-Brain scenario where both the appliances become the primary appliance, which can lead to service outages.

Q: Can each interface of the NetScaler be assigned a separate native VLAN?

A: Yes, each interface of the NetScaler can be assigned a separate native VLAN. 

Complete the following steps to change the native VLAN associated with interface 1/1 to VLAN 500:

  1. Create VLAN 500 on NetScaler:
    add vlan 500

  2. Bind VLAN 500 to interface 1/1 (ensure that you DO NOT use the -tagged option while binding)
    bind vlan 500 -ifnum 1/1

  3. Verify the configuration using the following command:
    show interface 1/1

    1)      Interface 1/1 (NetScaler Virtual Interface) #0
flags=0xe060 <ENABLED, UP, UP, HAMON, 802.1q>
MTU=1500, native vlan=500, MAC=9e:b9:8c:ab:e0:22, uptime 92h53m37s
LLDP Mode: NONE,                 LR Priority: 1024

RX: Pkts(1691709) Bytes(264035416) Errs(0) Drops(513720) Stalls(0)
TX: Pkts(1352731) Bytes(162819216) Errs(0) Drops(0) Stalls(0)
NIC: InDisc(0) OutDisc(0) Fctls(0) Stalls(0) Hangs(0) Muted(0)
Bandwidth thresholds are not set.

  4. Use the tagall option to tag the native VLAN on the interface.

Issue/Introduction

This article is an FAQ on "trunk" or "tagall" option in a NetScaler appliance.

Additional Information

Refer to Citrix Documentation for all operations that can be performed on "interface" command.

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