Channel Details

A channel is a combination of a Virtual IP (VIP) and a TCP port that the jetNEXUS ALB-X will listen on. Traffic arriving at the channel is directed to one of the content servers that are associated with that channel. The virtual IP address cannot be the same as the real address of the of the jetNEXUS ALB-X. i.e eth0, eth1 etc…

The jetNEXUS ALB-X determines how the traffic is distributed to the content servers based on a load balancing policy set within the Actions section.

To Create a new Channel

• 1.Click Add IP. The Status light will appear grey in colour and the Enabled box will be ticked.
• 2.Double click in the empty IP Address section. Enter the VIP address for your Channel. Example 192.168.1.100
• 3.Double click in the empty Subnet Mask section. Enter the subnet mask. Example 255.255.255.0
• 4.Double click in the empty Port section. Enter the TCP/UDP port the Channel will listen on.
• 5.Double click in the Service Type section. Choose the service type from the drop down menu.
• 6.Click Update.

Note: You may use the Tab key to move to the next box when configuring. For example, type in the IP Address and press the Tab key to move to the Subnet Mask section and so on.

Filtering and Sorting Columns

To the far right of each column is small down arrow (see the red box below). Clicking on this will reveal an extra submenu that allows you to “Sort Ascending”, “Sort Descending” and “Columns”. Add and remove the tick to show/hide the columns listed below.

Example

Primary

This column will remain empty unless the ALB-X is part of a High Availability (H/A) cluster. When in a H/A cluster a tick box will appear. Double click on the tick box to edit, single click to add a tick if you wish the ALB-X to be the primary ALB-X for the channel. Leave this blank if you wish the ALB-X to be a secondary for the channel. To configure high availability see Failover.

Status

• Online
• Failover-Standby. This virtual service is hot-standby
• Indicates a “secondary” is holding off for a “primary”
• Offline. Content servers are unreachable or no content servers enabled
• Finding status
• Not licensed or licensed Virtual IPs exceeded

Enabled

By default the box is ticked to enable the channel. Double click on the box to edit and single click to remove the tick. This will disable the channel.

IP Address

Double click to edit the column. Add in your IPv4 address in decimal dotted notation. This is the Virtual IP address for your service. Example “192.168.1.100”.

Subnet Mask

Double click to edit the column. Add in your subnet mask in decimal dotted notation. Example “255.255.255.0”.

Port

Double click to edit the column. Add in the port number associated with your service. This may be TCP or UDP port number. Example “80” for Web Traffic.

Service Name

Double click to edit the column. Add in a friendly name to identify your service. Example “Production Web Servers”.

Service Type

Layer 4 TCP:

Any TCP port (Layer 4)

Layer 4 UDP:

Any UDP port (Layer 4) This will change the connectivity to Basic and is only available in this mode

Layer TCP/UDP:

Any TCP or UDP port (Layer 4) This will change the connectivity to Basic and is only available in this mode. This is ideal if your service has a primary protocol such as UDP but will fall back to TCP

Accelerate HTTP:

HTTP(s) Protocol (Layer 7) with compression on the client side

HTTP:

HTTP(s) Protocol (Layer 7) without compression

FTP:

FTP Protocol (Layer 7)

SMTP:

Simple Mail Transfer Protocol (Layer 4)

POP3:

Post Office Protocol (Layer 4)

IMAP:

Internet Message Access Protocol (Layer 4)

RDP:

Remote Desktop Protocol (Layer 4)

RPC:

Remote Procedure Call (Layer 4)

RPC/ADS:

Exchange 2010 Static RPC for Address Book Service (Layer 4)

RPC/PF:

Exchange 2010 Static RPC for Public Folders (Layer 4)

DICOM:

Digital Imaging and Communications in Medicine (Layer 4)

Destination

The destination section contains the real content server details associated with the highlighted channel. You must add at least one content server to a channel. If you wish to weight a server then simply add in the same IP address and port more than once.

Example: – this weights 25% to Web Server 1 and 75% to Web Server 2

IP Address	Port	Notes
10.1.1.1	80	Web Server 1
10.1.1.2	80	Web Server 2
10.1.1.3	80	Web Server 2
10.1.1.4	80	Web Server 2

To add a new content server to a channel

• 1.Click Add New.
• 2.A new line will appear with a grey Status light.
• 3.Double click on the empty IP Address section. Enter the real IP address for your Content Server. The Content Server can be on a local network or any network that your jetNEXUS ALB-X can route to. Example “10.1.1.1”.
• 4.Double click on the empty Port section. Enter the TCP/UDP port the Content Server is listening on.
• 5.Double click on the Notes section. Add in some useful information about your content server.

Content Server Details

Content Server Group Name:

• This is name you can associate with a particular group of servers. For Example “Exchange 2010 CAS Array”.
• Click the middle Update button on the right hand side to save the group name.

Content Server Status Lights

• Connected
• Draining
• Offline
• Standby
• Not connected
• Finding status
• Not licensed or licensed real servers exceeded

Activity

By double clicking on the Activity section you can assign one of the four activities below.

Online:

Any content servers assigned as Online will load balance traffic.

Drain:

Any content servers assigned as Drain will continue to serve existing connections but will not accept any new connections. The Status light will flash Green/Blue whilst draining. Once the existing connections have closed naturally the content servers will be taken offline and the Status light will be solid blue.

Offline:

Any content servers assigned as Offline will immediately be taken offline and will not load balance traffic.

Standby:

Any content servers assigned as Standby will remain offline until ALL of the Online group fail, at which point members of the Standby group will load balance traffic. If one of the Online group becomes available they will start serving content and the Standby group will no longer load balance traffic.

IP Address

Double click to edit the column. Add in your IPv4 address in decimal dotted notation. This is the Real IP address for your content servers. Example “192.168.1.200”.

Port

Double click to edit the column. Add in the port number associated with your service. This is a TCP port number and does not have to match the virtual port. Example “80” for Web Traffic.

Notes

Double click to edit the column. Add in some useful notes about the particular server. Example “IIS Server1 – London DC”.

Actions

Load Balancing Policy

Select from the drop down list how you would like the traffic to be load balanced.

Round Robin:

The simplest method, each back end server takes a turn.

Least Connections:

The load balancer will keep track of the number of connections a back end server has and send the next request to the server with the least connections.

IP Bound:

In this situation the clients IP address is used to select which back end server will receive the request. This provides persistence. It can be used with HTTP or layer 4 protocols. This method is useful for internal networks where the network topology is known and you can be confident that there are no “super proxies” upstream. With layer 4 and proxies, all the requests can look as if they are coming from one client, and as such the load would not be even. With HTTP, X-Forwarded-For information is used, if present, to cope with proxies.

IP List Based:

The initial connection to the content server is made using “Least connections” then session affinity is achieved based on Clients IP. A list is maintained for 2 hours.

Cookie Based:

This is the most popular persistence method for HTTP. In this situation, IP list based load balancing is used for each first request. A cookie is inserted into the headers of the first http response. Thereafter, jetNEXUS ALB-X uses the client cookie to route traffic to the same back end server. Again this is used for persistence, when the client must go to the same back end server each time.

Session Cookie:

Classic ASP Session Cookie:
Active Server Pages (ASP) is a Microsoft server-side technology. With this option selected the ALB-X will maintain session persistence to the same server if an ASP cookie is detected and is found in its list of known cookies. If a new ASP cookie is detected then it will be load balanced using the least connections algorithm.

ASP.NET Session Cookie:
ASP.NET is a Microsoft server-side technology. With this option selected the ALB-X will maintain session persistence to the same server if an ASP.NET cookie is detected and is found in its list of known cookies. If a new ASP.NET cookie is detected then it will be load balanced using the least connections algorithm.

JSP Session Cookie:
Java Server Pages (JSP) is an Oracle server-side technology. With this option selected the ALB-X will maintain session persistence to the same server if a JSP cookie is detected and is found in its list of known cookies. If a new JSP cookie is detected then it will be load balanced using the least connections algorithm.

JAX-WS Session Cookie:
Java web services (JAX-WS) is an Oracle server-side technology. With this option selected the ALB-X will maintain session persistence to the same server if a JAX-WS cookie is detected and is found in its list of known cookies. If a new JAX-WS cookie is detected then it will be load balanced using the least connections algorithm.

PHP Session Cookie:
Personal Home Page (PHP) is an open source server-side technology. With this option selected the ALB-X will maintain session persistence to the same server if a PHP cookie is detected.

Connectivity

Your channel can be configured with four different types of connectivity. Please select one to apply to the channel.

Reverse Proxy:

This is the default setting for jetNEXUS ALB-X and works at Layer7 with compression and caching and also at layer4 without caching and compression. In this mode your jetNEXUS ALB-X acts as a reverse proxy and becomes the source address seen on the content servers.

Direct Server Return:

Direct Server Return or DSR as it’s widely known (DR – Direct Routing in some circles) allows the server behind the load balancer to respond directly to the client bypassing the edgeNEXUS on the response. DSR is suitable for using with Layer 4 load balancing only therefore Caching and Compression are not available when enabled.
Layer 7 load balancing with this method will not work therefore there is no persistence support other than IP List Based. SSL/TLS load balancing with this method is not ideal as there is only source IP persistence support. This method requires content server changes. Please refer to the content server changes section.

Transparency:

Transparency is suitable for Service Type Layer 4 load balancing only. Caching and Compression are not available when transparency is enabled. Transparency is used when you need the source address of the client making the request and X-Forwarded-For techniques are not sufficient. Layer 7 load balancing with this method will not work therefore there is no persistence support other than IP List Based. This method requires content server changes. Please refer to the content server changes section.

Gateway:

Gateway mode allows you to route all traffic through the jetNEXUS, this allows traffic from the content servers to be routed via the edgeNEXUS to other networks via the interfaces on the edgeNEXUS unit. Using the device as a gateway device for content servers should be used when running in multi interface mode. Layer 7 load balancing with this method will not work therefore there is no persistence support other than IP List Based. This method requires that the content server sets its default gateway to the local interface address (eth0, eth1, etc….) of the jetNEXUS ALB-X. Please refer to the content server changes section.

Basic:

Basic mode is a very low latency low CPU mode that will provide simple load balancing. The load balancing policy is restricted to Round Robin or if you require session persistence IP List Based. This mode is only available with the 64bit platform which is available from here.

Content SSL Certificate (Encrption between ALB-X and Content Server)

By default this is set to No SSL. If your server requires an encrypted connection then this must be set to anything other than No SSL. Certificates that have been created or imported will appear in this list.

No SSL:

Traffic from the ALB-X to the content server will not be encrypted.
If a certificate has been selected – on the browser side, “No SSL” can be selected client-side to provide what is known as “SSL Offload”.

UserCertificate1:

Traffic from the ALB-X to the content server will be encrypted provided the named certificate is presented by the content server.
If a certificate has been selected – on the browser side, “UserCertificate1” can be selected to provide what is known as “SSL Bridging” or “SSL Re-Encryption”.

Any:

The ALB-X acts as a client and will accept any certificate the content server presents. Traffic from the ALB-X to the content server will be encrypted if this is selected.
If a certificate has been selected – on the browser side, “Any” can be selected to provide what is known as “SSL Bridging” or “SSL Re-Encryption”.

Enable Connection Pooling

When this is ticked the ALB-X maintains connections to the content server so they can be reused when future requests to the content servers are requested. This setting is only valid for Service Type “HTTP” and should be used for stateless web connections only.

Connection Pool Size

Set the number of connections to maintain.

flightPATH

• flightPATH rules are designed to manipulate HTTP(s) traffic. As such, the option for flightPATH is not visible for non HTTP protocols.
• The list of available rules is on the right and the current rules applied to the channel are on the left.
• To add a new rule drag and drop the rule into position.
• The order for execution is important and will start with the top rule being executed fist. To change the order highlight a rule and use the arrows to move up or down the list.
• To remove a rule simply drag and drop it back to the rule inventory.
• You can add, remove and edit flightPATH rules in the Configure flightPATH section.
• Please note that any flightPATH rule with an Action that includes ‘Body Replace’ will effectively turn off compression for the channel to which it is applied.