Video Screencast Help

LLT over or UDP or Ethernet

Created: 11 Dec 2013 • Updated: 27 Dec 2013 | 9 comments
mokkan's picture
This issue has been solved. See solution.

Hello,

 

When to setup hearbeat Link, which one we need to choose LLT over Ethernet or UDP? Can you explain the senario when to use Ethernet and when to use UDP?

 

Operating Systems:
Discussion Filed Under:

Comments 9 CommentsJump to latest comment

mikebounds's picture

Usually you should use LLT over Ethernet - you only need to use UDP if  you need a route between your links as LLT over Ethernet is non routable.

Mike

UK Symantec Consultant in VCS, GCO, SF, VVR, VxAT on Solaris, AIX, HP-ux, Linux & Windows

If this post has answered your question then please click on "Mark as solution" link below

Gaurav Sangamnerkar's picture

Symantec recommends that you configure heartbeat links that use LLT over Ethernet, unless hardware requirements force you to use LLT over UDP. If you want to configure LLT over UDP, make sure you meet the prerequisites.

UDP makes LLT packets routable and thus able to span longer distances more economically.

Reder to admin guide for building the understanding

https://sort.symantec.com/public/documents/sfha/6....

 

G

 

PS: If you are happy with the answer provided, please mark the post as solution. You can do so by clicking link "Mark as Solution" below the answer provided.
 

SOLUTION
Gaurav Sangamnerkar's picture

Also to note, The LLT-over-UDP configuration works over the IP layer, and is therefore a little slower than the LLT-over-Ethernet configuration

G

PS: If you are happy with the answer provided, please mark the post as solution. You can do so by clicking link "Mark as Solution" below the answer provided.
 

SOLUTION
mokkan's picture

Thank you Very much for all the info.  If I understand correctly,  if we are configuring LLT in same subnet don't need the UDP.  If we are confiuguring LLT and needs to be routed through different network, then need to configure UDP. Am I right?

mikebounds's picture

Thats correct.

UK Symantec Consultant in VCS, GCO, SF, VVR, VxAT on Solaris, AIX, HP-ux, Linux & Windows

If this post has answered your question then please click on "Mark as solution" link below

SOLUTION
mokkan's picture

There is a document to add low priority link using public network. What does it mean by public network?

If we are using public network I can't use LLT over ethernet right ? I need to  use LLT over UDP right? I need to have mix of LLT over thernet and UDP ?

Gaurav Sangamnerkar's picture

After configuring 2 high priority link for LLT, you can keep addition redundancy by having a low pri link. This low pri link is usually the public network link on server which is configured for accessing applications or database on server.

High priority links are used for cluster communications to GAB as well as heartbeat signals. Low priority links, during normal operation, are used for heartbeat and link state maintenance only, and
the frequency of heartbeats is reduced to 50% of normal to reduce network overhead.
If there is a failure of all configured high priority links, LLT will switch all cluster communications traffic to the first available low priority link. Communication traffic will revert back to the high priority links as soon as they
become available.

Also, note, if its a SFRAC setup, Symantec does not recommend using low pri link as it may flood SFRAC data if high pri links fail

https://sort.symantec.com/public/documents/vcs/5.1...

As long as connection is made for low pri link & LLT can detect it, I don't believe there is any specific recommendation to use low pri link on UDP

 

G

PS: If you are happy with the answer provided, please mark the post as solution. You can do so by clicking link "Mark as Solution" below the answer provided.
 

mikebounds's picture

"public network" means it is a network used by other things (i.e it has IP addresses assigned) as oppose to a private network which is private just for LLT.

A low-pri heartbeat on a "public network" can still use LLT over Ethernet (so LLT doesn't use the IPs on the interfaces) and this is the norm.

You cannot use a mix of LLT over ethernet and UDP - you must use one or the other for all links (including low-pri)

Mike

UK Symantec Consultant in VCS, GCO, SF, VVR, VxAT on Solaris, AIX, HP-ux, Linux & Windows

If this post has answered your question then please click on "Mark as solution" link below

SOLUTION
mokkan's picture

thank you very much for all the answers