In Clustering
In Citrix ADC 13.0
In Citrix ADC
In All products
Product documentation
In Clustering
In Citrix ADC 13.0
In Citrix ADC
In All products
Clustering
13.0 12.1 12.0 11.1 10.5
View PDF

Communication in a cluster setup

September 21, 2020
Contributed by: 
S

The interfaces of Citrix ADC appliances that are added to a cluster, are prefixed with a node ID. This helps identify the cluster node to which the interface belongs. Therefore, the interface identifier c/u, where c is the controller number and u is the unit number, now becomes n/c/u, where n is the node ID. For example, in the following figure, interface 1/2 of node n1 is represented as 0/1/2, interface 1/1 of node n2 is represented as 1/1/1, and interface 1/4 of node n3 is represented as 2/1/4.

Figure 1. Interface naming convention in a cluster

localized image

  • Server communication- The cluster communicates with the server through the physical connections between the cluster node and the server-side connecting device. The logical grouping of these physical connections is called the server data plane.
  • Client communication- The cluster communicates with the client through the physical connections between the cluster node and the client-side connecting device. The logical grouping of these physical connections is called the client data plane.
  • Inter-node communication- The cluster nodes can also communicate with each other. The manner in which they communicate depends on whether the node exists on the same network or across networks.
    • Cluster nodes within the same network communicate with each other by using the cluster backplane. The backplane is a set of interfaces in which one interface of each node is connected to a common switch, which is called the cluster backplane switch. The different types of traffic that goes through backplane, which is used by internode communication are:
      • Node to Node Messaging (NNM)
      • Steered traffic
      • Configuration propagation and synchronization
    • Each node of the cluster uses a special MAC cluster backplane switch address to communicate with other nodes through the backplane. The cluster special MAC is of the form: 0x02 0x00 0x6F <cluster_id> <node_id> <reserved>), where cluster_id is the cluster instance ID, node_id is the node number of the Citrix ADC appliance that are added to a cluster.

The following figures shows the communication interfaces in L2 clusters and L3 clusters.

Figure 2. Cluster communication interfaces - L2 cluster

localized image

Figure 3. Cluster communication interfaces - L3 cluster

localized image

Communication in a cluster setup

September 21, 2020
Contributed by: 
S
September 21, 2020
Contributed by: 
S

In this article