Cisco CSS 11501 - High-Availabilty

jdanrich · ‎03-17-2003

We have a single CSS 11501 and were thinking about just buying a new one and putting it online as the standby with statefull (hopefully) failover, but weren't sure that this would work.

Does anyone know what is needed to create a high-availability Cisco CSS 11501 environment?

Do you only need 2 CSS 11501 and then configure them with one being active and the other being in a standby mode, like a PIX?

Is there a HA Cable that would need to be connected between the 2 CSS's?

Thanks in Advanced.

Joe

pknoops · ‎03-17-2003

Joe,

The answer to your question is yes and yes.

You can have the CSS boxes as active/backup as we call it which is what you describe above. One box is active, the other is in standby mode with an identical config and a cross-over cable between them.

The other option is to go with an active/active senario whereby both boxes are active and each has dedicated VIP addresses on them whereby they back each other up. This would be termed VIP redundancy. In this case if a packet comes in on box a and the active vip is actually being served on box b, boz a will L2 forward the packet over to box b.

It certainly gets alot more involved but you certainly gain alot by purchasing another box and go with either method.

Regards

Pete Knoops

Cisco Systems

jdanrich · ‎03-17-2003

Peter,

Thanks for the information.

With the purchase of a new unit, is there some sort of license that would have to be purchased to use the unit in one of the environments that you described?

Also, when you talk about a cross-over cable, is this a special cable that is needed or is this a standard Cat5 X-Over?

Thanks,

Joe

pknoops · ‎03-17-2003

Joe,

No special license is needed and the cable is a simple Cat5 X-over

Pete..

dcayer · ‎03-17-2003

Peter,

With box-to-box redundancy, is statefull fail-over support? i.e.: will the CSS exchange flow tables so that fail-over can be completely transparent for end-users browsing pages on the web servers? (in our case, we also have SCA's attached in the one-armed-transparent configuration).

Thanks,

Daniel Cayer

EDS Canada

jdanrich · ‎03-17-2003

So from what I can gather here, all I would need is another CSS that would be set as an active or passive backup to the one that is always on-line.

Does this sound correct?

pknoops · ‎03-17-2003

That is correct. It sounds easy, and quite honestly it is. I have been working on this box for 3yrs (including when I worked for Arrowpoint Communications) and it is as easy as it sounds :)

Pete..

pknoops · ‎03-17-2003

Daniel,

There is a new stateful failover mechanism for the Cisco CSS 11500.

This description is a bit "salesy" I know, but it covers the question asked :-)

The Cisco CSS 11500 delivers ASR—the industry's first stateful Layer 5 session redundancy feature that enables failover of important flows while maximizing performance. Some flows—such as a long-lived File Transfer Protocol (FTP) or a database session — may be mission critical, but many are not. Most solutions on the market today require all traffic—important or not—to be backed up from one box to another. If the majority of flows are not critical, then most of system performance is wasted on unnecessary back

ups. With ASR, the Cisco CSS 11500 may be configured so critical flows are marked as replication worthy, whereas others do not need to be so marked. ASR focuses traffic management resources precisely where needed.

Better yet, have a look at the following link focusing on the section on Stateless Redundancy.

http://www.cisco.com/univercd/cc/td/doc/product/webscale/css/css_510/advcfggd/redndncy.htm

Regards

Pete..

jdanrich · ‎03-17-2003

Thanks for all of the info... Even if it was a bit "Salesy" 8^P

Looks like what we will do is purchase a second one and place it into passive mode as the backup.

dcayer · ‎03-18-2003

Thanks Pete!

PS: We're expecting a new 11500 soon, which I'll be able to play with for a while... but I won't have a 2nd one to test the stateful redundancy! :-(