Product Documentation

Configuring a CloudBridge Connector Tunnel between two Datacenters

Dec 01, 2015

You can configure a CloudBridge Connector tunnel between two different datacenters to extend your network without reconfiguring it, and leverage the capabilities of the two datacenters. A CloudBridge Connector tunnel between the two geographically separated datacenters enables you to implement redundancy and safeguard your setup from failure. The CloudBridge Connector tunnel helps achieve optimal utilization of infrastructure and resources across datacenters. The applications available across the two datacenters appear as local to the user.

To connect a datacenter to another datacenter, you set up a CloudBridge Connector tunnel between a NetScaler appliance in one datacenter and a NetScaler appliance in the other datacenter.

As an illustration of CloudBridge Connector tunnel between datacenters, consider an example in which a CloudBridge Connector tunnel is set up between NetScaler appliance NS_Appliance-1 in datacenter DC1 and NetScaler appliance NS_Appliance-2 in datacenter DC2.

Both NS_Appliance-1 and NS_Appliance-2 function in L2 and L3 mode. They enable communication between private networks in datacenters DC1 and DC2. In L3 mode, NS_Appliance-1 and NS_Appliance-2 enable communication between client CL1 in datacenter DC1 and server S1 in the datacenter DC2 through the CloudBridge Connector tunnel. Client CL1 and server S1 are on different private networks.

Because client CL1 and server S1 are on different private networks, L3 mode is enabled on NS_Appliance-1 and NS_Appliance-2, and routes are updated as follows:
  • CL1 has a route to NS_Appliance-1 for reaching S1.
  • NS_Appliance-1 has a route to NS_Appliance-2 for reaching S1.
  • S1 has a route to NS_Appliance-2 for reaching CL1.
  • NS_Appliance-2 has a route to NS_Appliance-1 for reaching CL1.

The following table lists the settings on NetScaler appliance NS_Appliance-1 in datacenter DC1.

Entity Name Details
The NSIP address 198.51.100.12
SNIP address 198.51.100.15
CloudBridge Connector tunnel Cloud_Connector_DC1-DC2
  • Local endpoint IP address of the CloudBridge Connector tunnel: 198.51.100.15
  • Remote endpoint IP address of the CloudBridge Connector tunnel: 203.0.113.133
GRE Tunnel Details
  • Name = Cloud_Connector_DC1-DC2
IPSec Profile Details
  • Name = Cloud_Connector_DC1-DC2
  • Encryption algorithm = AES
  • Hash algorithm = HMAC SHA1
The following table lists the settings on NetScaler appliance NS_Appliance-2 in datacenter DC2.
Entity Name Details
The NSIP address 203.0.113.131
SNIP address 203.0.113.133
CloudBridge Connector tunnel Cloud_Connector_DC1-DC2
  • Local endpoint IP address of the CloudBridge Connector tunnel: 203.0.113.133
  • Remote endpoint IP address of the CloudBridge Connector tunnel: 198.51.100.15
GRE Tunnel Details
  • Name = Cloud_Connector_DC1-DC2
IPSec Profile Details
  • Name = Cloud_Connector_DC1-DC2
  • Encryption algorithm = AES
  • Hash algorithm = HMAC SHA1
Following is the traffic flow in the CloudBridge Connector tunnel:
  1. Client CL1 sends a request to server S1.
  2. The request reaches NetScaler appliance NS-Appliance-1.
  3. NS_Appliance-1 checks its routing table and finds that the destination IP address of the request packets belong to a subnet in datacenter DC2.
  4. NS_Appliance-1 uses the GRE protocol to encapsulate each of the request packets by adding a GRE header and a GRE IP header to the packet. The GRE IP header has the destination IP address set to the IP address of the CloudBridge tunnel ( CC-DC1-DC2 ) end point in DC2. This IP Address is a public SNIP address configured on NS_Appliance-2.
  5. For CloudBridge Connector tunnel CC-DC1-DC2, NS_Appliance-1 checks the stored IPSec security association (SA) parameters for processing outbound packets, as agreed between NS_Appliance-1 and NS_Appliance-2. The IPSec Encapsulating Security Payload (ESP) protocol in NS_Appliance-1 uses these SA parameters for outbound packets to encrypt the payload of the GRE encapsulated packet.
  6. The ESP protocol ensures the packet's integrity and confidentiality by using the HMAC hash function and the encryption algorithm specified for CloudBridge Connector tunnel CC-DC1-DC2. The ESP protocol, after encrypting the GRE payload and calculating the HMAC, generates an ESP header and an ESP trailer and inserts them before and at the end of the encrypted GRE payload, respectively.
  7. The resulting packet is sent to NS_Appliance-2.
  8. NS_Appliance-2 checks the stored IPSec security association (SA) parameters for processing inbound packets, as agreed between NS_Appliance-1 and NS_Appliance-2 for the CloudBridge Connector tunnel CC-DC1-DC2. The IPSec ESP protocol on NS_Appliance-2 uses these SA parameters for inbound packets, and the ESP header of the request packet, to decrypt the packet.
  9. NS_Appliance-2 then decapsulates the packet by removing the GRE header.
  10. The resulting packet is the same packet as the one received by NS_Appliance-1 in step 2. This packet has the destination IP address set to the IP address of server S1. NS_Appliance-2 forwards this packet to server S1.
  11. S1 processes the request packets and sends response packets. The destination IP address in the response packets is the IP address of client CL1, and the source IP address is the IP address of server S1.
  12. The response packets reach NS_Appliance-2.
  13. NS_Appliance-2 encapsulates and encrypts the response packets in the same way that NS_Appliance-1 encrypted the request packets in steps 3-6.
  14. NS_Appliance-2 sends the resulting packets to NS_Appliance-1.
  15. NS_Appliance-1, upon receiving the packets from NS_Appliance-2, decrypts and decapsulates them in the same way that NS_Appliance-2 did with the request packets in steps 9-11.

Prerequisites for Configuring a CloudBridge Connector tunnel between two Datacenters

Before setting up a CloudBridge Connector tunnel, verify that the following tasks have been completed:

  1. Deploy and set up a NetScaler appliance in each of the two datacenters.
  2. Make sure that the CloudBridge Connector tunnel end-point IP addresses are accessible to each other.

Configuration Procedure

To set up a CloudBridge Connector tunnel between a NetScaler appliance that resides in one datacenter and another NetScaler appliance that resides in the other datacenter, use the configuration utility or the command line interface of one of the NetScaler appliances.

When you use the configuration utility, the CloudBridge Connector tunnel configuration created on the first NetScaler appliance is automatically pushed to the other endpoint (the other NetScaler appliance) of the CloudBridge Connector tunnel. Therefore, you do not have to access the configuration utility of the other NetScaler appliance to create the corresponding CloudBridge Connector tunnel configuration on it.

The CloudBridge Connector tunnel configuration on each of the NetScaler appliances consists of the following entities:

  • IPSec profile—An IPSec profile entity specifies the IPSec protocol parameters, such as IKE version, encryption algorithm, hash algorithm, and PSK, to be used by the IPSec protocol in the CloudBridge Connector tunnel.
  • GRE tunnel—An IP tunnel specifies the local IP address (a public SNIP address configured on the local NetScaler appliance), remote IP address (a public SNIP address configured on the remote NetScaler appliance), protocol (GRE) used to set up the CloudBridge Connector tunnel, and an IPSec profile entity.
  • Create a PBR rule and associate the IP tunnel with it—A PBR entity specifies a set of conditions and an IP tunnel entity. The source IP address range and the destination IP range are the conditions for the PBR entity. You must set the source IP address range and the destination IP address range to specify the subnet whose traffic is to traverse the CloudBridge Connector tunnel. For example, consider a request packet that originates from a client on the subnet in the first datacenter and is destined to a server on the subnet in the second datacenter. If this packet matches the source and destination IP address range of the PBR entity on the NetScaler appliance in the first datacenter, it is sent across the CloudBridge Connector tunnel associated with the PBR entity.

To create an IPSEC profile by using the command line interface

At the command prompt, type:

add ipsec profile <name> [-ikeVersion ( V1 | V2 )] [-encAlgo ( AES | 3DES ) ...] [-hashAlgo <hashAlgo> ...] [-lifetime <positive_integer>] (-psk | (-publickey <string> -privatekey <string> -peerPublicKey <string>)) [-livenessCheckInterval <positive_integer>] [-replayWindowSize <positive_integer>] [-ikeRetryInterval <positive_integer>] [-retransmissiontime <positive_integer>]

Example

add ipsec profile Cloud_Connector_DC1-DC2 
-encAlgo AES -hashAlgo HMAC_SHA1

To create an IP tunnel and bind the IPSEC profile to it by using the command line interface

At the command prompt, type:

add ipTunnel <name> <remote><remoteSubnetMask> <local> [-protocol <protocol>] [-ipsecProfileName <string>]

Example

add ipTunnel Cloud_Connector_DC1-DC2 203.0.113.133 255.255.255.255 198.51.100.15 -protocol GRE -ipsecProfileName Cloud_Connector_DC1-DC2

To create a PBR rule and bind the IPSEC tunnel to it by using the command line interface

At the command prompt, type:

  • add ns pbr <pbr_name> ALLOW -srcIP = <local_subnet_range> -destIP = <remote_subnet_range> -ipTunnel <tunnel_name>
  • apply ns pbrs

Example

  • add ns pbr PBR-DC1-DC2 ALLOW -srcIP 198.51.100.15 -destIP 203.0.113.133 ipTunnel Cloud_Connector_DC1-DC2
  • apply ns pbrs

To configure a CloudBridge Connector tunnel in a NetScaler appliance by using the configuration utility

  1. Type the NSIP address of a NetScaler appliance in the address line of a web browser.
  2. Log on to the configuration utility of the NetScaler appliance by using your account credentials for the appliance.
  3. Navigate to System > CloudBridge Connector.
  4. In the right pane, under Getting Started, click Create/Monitor CloudBridge.

    The first time you configure a CloudBridge Connector tunnel on the appliance, a Welcome screen appears.

  5. On the Welcome screen click Get Started.
    Note: If you already have a CloudBridge Connector tunnel configured on the NetScaler appliance, the Welcome screen does not appear, so you do not click Get Started.
  6. In the CloudBridge Connector Setup pane, click NetScaler.

     

  7. In the NetScaler pane, provide your account credentials for the remote NetScaler appliance. Click Continue.
  8. In the CloudBridge Connector Setting pane, set the following parameter:
    • CloudBridge Connector Name—Name for the CloudBridge Connector configuration on the local appliance. Must begin with an ASCII alphabetic or underscore (_) character, and must contain only ASCII alphanumeric, underscore, hash (#), period (.), space, colon (:), at (@), equals (=), and hyphen (-) characters. Cannot be changed after the CloudBridge Connector configuration is created.
  9. Under Local Setting, set the following parameter:
    • Subnet IP—IP address of the local endpoint of the CloudBridge Connector tunnel. Must be a public IP address of type SNIP.
  10. Under Remote Setting, set the following parameter:
    • Subnet IP—IP address of the peer endpoint of the CloudBridge Connector tunnel. Must be a public IP address of type SNIP.
  11. Under PBR Setting, set the following parameters:
    • Operation—Either the equals (=) or does not equal (!=) logical operator.
    • Source IP Low*—Lowest source IP address to match against the source IP address of an outgoing IPv4 packet.
    • Source IP High—Highest source IP address to match against the source IP address of an outgoing IPv4 packet.
    • Operation—Either the equals (=) or does not equal (!=) logical operator.
    • Destination IP Low*—Lowest destination IP address to match against the destination IP address of an outgoing IPv4 packet.
    • Destination IP High—Highest destination IP address to match against the destination IP address of an outgoing IPv4 packet.
  12. (Optional) Under Security Settings, set the following IPSec protocol parameters for the CloudBridge Connector tunnel:
    • Encryption Algorithm—Encryption algorithm to be used by the IPSec protocol in the CloudBridge tunnel.
    • Hash Algorithm—Hash algorithm to be used by the IPSec protocol in the CloudBridge tunnel.
    • Key—Select one of the following IPSec authentication methods to be used by the two peers to mutually authenticate.
      • Auto Generate Key—Authentication based on a text string, called a pre-shared key (PSK), generated automatically by the local appliance. The PSKs keys of the peers are matched against each other for authentication.
      • Specific Key—Authentication based on a manually entered PSK. The PSKs of the peers are matched against each other for authentication.
        • Pre Shared Security Key—The text string entered for pre-shared key based authentication.
      • Upload Certificates—Authentication based on digital certificates.
        • Public Key—A local digital certificate to be used to authenticate the local NetScaler appliance to the peer before establishing IPSec security associations. The same certificate should be present and set for the Peer Public Key parameter in the peer.
        • Private Key—Private key of the local digital certificate.
        • Peer Public Key—Digital certificate of the peer. Used to authenticate the peer to the local end point before establishing IPSec security associations. The same certificate should be present and set for the Public key parameter in the peer.
  13. Click Done.

The new CloudBridge Connector tunnel configuration on both the NetScaler appliances appears on the Home tab of the respective configuration utility. The current status of the CloudBridge connector tunnel is indicated in the Configured CloudBridge Connectors pane. A green dot indicates that the tunnel is up. A red dot indicates that the tunnel is down.