WCCP or In Line???

[Dan Loring]

I do not know why any one would go the route of WCCP, other than a limitation of existing router/Switch design.  Can someone shed some more light on the basic advantages of both.  It seems to me that WCCP would create more capacity on the edge router slowing it down??

[Gavin Barber]

I find WCCP is much easier to implement for High Availability and Redundancy. It also allows you to do maintenance works easier than an inline solution. You can simply add another device to the WCCP service group.

When you operate inline, the inline device also has to work harder to inspect all traffic before passing it to the edge, whereas with WCCP you specify what traffic gets redirected for proxying. With my experience of setting up WCCP this adds little overhead to the edge device.

I have had to convert quite a few systems from inline deployments to WCCP due to issues inline creating interface failures and generating some really weird scenarios where devices would flap between each other. I've never had this experience once I've converted to WCCP deployment.

I will admit I've never been involved in the original inline deployments and they could have been bad installs but when I've converted to WCCP the benefits were easily seen. The only major hurdle with WCCP is troubleshooting traffic paths to make sure WCCP is redirecting traffic as you expect it to.

[Dan Loring]

I can see the service being easier, but with using inline or wccp I would want it to inspect all the packets coming threw, isn't it designed to sit on the edge of the WAN and optimize all packets going accross it(WAN)??  Also with WCCP it is using one nic to pull the packets down optimize and use the same nic to send the packets accross the WAN, with inline it is using two nics to send receive. Not trying to be a pain just trying to sell myself on WCCP, because that is what we are using and I am not too impressed with it. 

Thanks,

Dan

[Gavin Barber]

If you are wanting to inspect all packets then inline is definitely the way to go forward, but be warned if your inline device fails all outbound connectivity is going to be lost with it. That is my major caution with inline, although some hardware will support open pass through failure.

If you simply want to redirect specific ports/traffic and proxy them through an appliance then WCCP is what you want to do. You are correct in thinking WCCP host will only use on NIC for connectivity, but with multiple WCCP hosts in the service group that gives you the resililiency. Using the service group to target that traffic with an ACL you can be very specific on the edge device on what you want to redirect, reducing load.

What are the problems you are experiencing with WCCP? I have seen deployments where all traffic is getting WCCP redirected and then routed back to the edge device and this would create a significant overhead on both the edge device and the WCCP device as the traffic will be getting inspected twice. In my opinion the efficiency is in the detail when you setup WCCP.

Hope that helps.

[Bhavin Yadav]

Hi Dan,

To add little more value to what Gavin has said, there are lot of things that count and can help decide whether you want to use WCCP or inline.

Few of them are:

1. Hardware and software version of routers / switches that will work with WAAS.

2. IOS feature set of the routers or switches that will work with WAAS.

3. How much traffic and what traffic you want to optimize / pass through.

4. Redundancy and failover requirement.

5. Cost of appliances.

6. The reliability and fault tolerance requirements.

7. Redundacy, load sharing and load balancing requirements.

There are lot more other things that can play a key role in your decision.

The following link should help you understand the advantages and disadvantages of WCCP and inline.

http://www.cisco.com/en/US/docs/app_ntwk_services/waas/waas/v431/configuration/guide/planning.html#wp1041913

Hope this helps.

Regards.

PS: Please mark this as Answered, if this answers your question.