Using separate interface for replication

I have 1 ip on either site to use as a replication link. I have 2 nodes in primary site and 1 node in secondary site. There is no issue creating a replication link at DR site but in Primary site having 2 nodes to select one ip to replicate is a challenge I have.

The key point is: you should not normally select one physical node’s IP as the replication IP when the Primary site has two nodes.

For your topology:

Primary Site: Node 1 + Node 2
DR Site: Node 3
Replication IP: 1 IP at Primary + 1 IP at DR

The preferred design is to use a virtual/cluster IP (VIP) at the Primary site for replication. That VIP should be able to move between Node 1 and Node 2 if one node fails.

So the communication would look like:

Primary Cluster VIP → DR Node IP

If your replication product specifically requires a replication IP configured on each node, then you would need:

Node 1 → Replication IP 1
Node 2 → Replication IP 2
DR Node → Replication IP

With only one Primary-site IP, the correct approach depends on whether your replication software supports a cluster/virtual replication IP.

If you tell me the exact product/technology you're using for replication, I can give you the exact configuration for your 2-node Primary → 1-node DR setup.

Hi,

Yes—there are two nodes at the Primary site with a single IP address available for use as the replication endpoint, whereas the Secondary/DR site has only one node.
Given that only one physical IP address is available at the Primary site, a Virtual IP (VIP) or a different replication architecture is required, depending on the specific Sangfor features and version. However, using a VIP alone does not necessarily resolve the inter-node replication issue, as the replication service may require each physical node to have its own accessible address.

Let's assume that the IP layout is as follows. One DR node and two primary nodes.
One IP address from each site that has the same subnet and vlan ID has been provided by the NOC team.

VLAN ID: 50; primary: 10.10.50.50
DR: 10.20.50.50 and VLAN ID: 50

Does this work? GW 10.10.50.1 10.20.50.1 Primary Site DR Site Node1 10.10.50.3 10.20.50.3 Node2 10.10.50.4 Cluster 10.10.50.2 SCP 10.10.50.6 10.20.50.6

Solvia confirms that same subnet/vlan as management interface could not be used for another interface on the same host.

I would set it up like this if you are unable to make another VLAN or subnet:

Site,           Node,          Management IP,     DR Role,
Primary      Node 1,      10.x.x.11,                 DR Transmission/Controller,
Primary      Node 2,      10.x.x.12,                 DR Proxy,
DR,             Node 3,      10.x.x.21,                 DR Transmission

The specific IPs are merely illustrations.

What matters is:

Never attempt to give both primary nodes the same DR IP. Every node has a management IP already. While the second node employs the DR proxy method, the DR mechanism can make use of the transmission interface/IP of the controller.

Just an update tried configuring the IP at DR site and got this error message. The node's interface channel1 ip address is conflicting. Please modify it and try again. Error code: B1400604

So hypothetically lets say the IP layout is as follows. 2 nodes in primary 1 node in DR.
The NOC team has provided 1 ip from each site which shares the same subnet and vlan ID.

Primary - 10.10.50.50 with VLAN ID - 50
DR - 10.20.50.50 with VLAN ID - 50

Will this work?


        Primary Site        DR Site
GW        10.10.50.1        10.20.50.1
Node1        10.10.50.3        10.20.50.3
Node2        10.10.50.4       
Cluster        10.10.50.2       
SCP        10.10.50.6        10.20.50.6
               
VLAN ID        50        50
Subnet         /26        /26

i agree, it's for better and for easy access and management purpose, it help my organization a lot, especially in replica and redundant site

If you cannot create another VLAN/subnet, I would configure it like this:

Site        Node        Management IP        DR Role
Primary        Node 1        10.x.x.11        DR Transmission / Controller
Primary        Node 2        10.x.x.12        DR Proxy
DR        Node 3        10.x.x.21        DR Transmission

The exact IPs are only examples.

The important thing is:

Do not try to assign the same DR IP to both Primary nodes. Each node already has its own Management IP. The DR mechanism can use the controller's transmission interface/IP while the second node uses the DR proxy mechanism.

The challenge is we need to use the same VLAN and the subnet as the management interface.