Spanning Tree Protocol (STP) in NetScaler Appliance

来源 https://support.citrix.com/article/CTX112341

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Information

This contains information about Spanning Tree Protocol (STP) in the NetScaler Appliance.

Spanning Tree Protocol

STP is a link layer network protocol used to avoid Layer 2 loops (bridge loops) which is commonly used on network switches. The best practice is to disable STP on the interfaces that are connected to the NetScaler appliance because STP can interfere with proper operation during 30 to 50 seconds that the ports are in the LISTENING or LEARNING states. For instance, while the switch ports are in Listening/Learning states:

• The NetScaler appliances that are in a High Availability (HA) setup cannot receive HA heartbeats from their neighbor, which results in both nodes going into the PRIMARY state.
• The NetScaler appliance might reset its interfaces to resolve an interface problem. It resets the port back to LISTENING state on the switch and this cycle could continue forever.
• ARPs and GARPs might be lost, interfering with the operation between the primary and secondary appliances.

With L2 mode disabled (the default setting), the appliance does not switch packets between interfaces in the same virtual LAN, a layer 2 loop cannot exist. Therefore, enabling STP on the interfaces connected to the appliance is not necessary. However, if it is a requirement to enable STP on the ports connected to the appliance, configure Rapid Spanning Tree Protocol (RSTP),to resolve the preceding issues.

In cases where L2 mode on the appliance should be enabled, you must consider the following aspects:

• The NetScaler appliances do not participate in the spanning tree.
• With mode Bridge BPDUs: OFF (the default mode), or with older NetScaler software releases that did not have the Bridge BPDUs mode as an option, the NetScaler appliance drops all BPDUs received on an interface.
• With L2 mode enabled, the appliance switches other frames (such as broadcasts) between two interfaces configured in and connected to the same VLAN.

When you consider the preceding aspects, it could lead to a switching loop that spanning tree might not be able to resolve. You must ensure that a loop-free network at layer 2 before enabling L2 mode. Additionally, if L2 mode is a requirement, it is recommended to ensure that the NetScaler software release installed on the appliance includes the Bridge BPDUs mode in the ON state.

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信息

其中包含有关NetScaler Appliance中生成树协议（STP）的信息。

生成树协议

STP是一种链路层网络协议，用于避免在网络交换机上常用的第2层环路（网桥环路）。最佳做法是在连接到NetScaler设备的接口上禁用STP，因为STP可能会在端口处于“收听”或“学习”状态的30到50秒内干扰正常操作。例如，当交换机端口处于侦听/学习状态时：

• 处于高可用性（HA）设置的NetScaler设备无法从其邻居接收HA心跳，这导致两个节点都进入PRIMARY状态。
• NetScaler设备可能会重置其接口以解决接口问题。它将端口重置为交换机上的LISTENING状态，此循环可以永久持续。
• ARP和GARP可能会丢失，从而干扰主设备和辅助设备之间的操作。

禁用L2模式（默认设置）后，设备不会在同一虚拟LAN中的接口之间切换数据包，不能存在第2层环路。因此，无需在连接到设备的接口上启用STP。但是，如果要求在连接到设备的端口上启用STP，请配置快速生成树协议（RSTP）以解决上述问题。

如果应启用设备上的L2模式，则必须考虑以下方面：

• NetScaler设备不参与生成树。
• 对于模式桥接BPDU：OFF（默认模式），或者没有选择Bridge BPDU模式的旧NetScaler软件版本，NetScaler设备会丢弃接口上收到的所有BPDU。
• 启用L2模式后，设备会在配置并连接到同一VLAN的两个接口之间切换其他帧（例如广播）。

当您考虑前面的方面时，它可能会导致生成树可能无法解析的切换循环。在启用L2模式之前，必须确保第2层的无环路网络。此外，如果需要L2模式，建议确保设备上安装的NetScaler软件版本包含处于ON状态的Bridge BPDU模式。

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NetScaler 集成的 ZebOS 网络模块。

ZebOS 7.8.1 support Protocol Daemons
Each routing and switching protocol supported in the ZebOS suite runs in a separate daemon, built from individual source files. Code updates, patches and enhancements are applied on a module-by-module basis without disrupting other running protocols. The following table lists the daemon file names for the operating systems (OS) supported by ZebOS. No indicates that a protocol is not supported for an OS.

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