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Community Member

waas appliance and manager setup

Hi all

we have waas in my new company, we use wccp on the router.

Can anyone explain simply how my traffic will be optimized? will my waas appliance not be an inline appliance, does the traffic flow to the appliance then back to the router? how will the physical connections and traffic flow look? and how does the wccp work ?

hope someone can help



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Cisco Employee

waas appliance and manager setup

hi Carl,

WAAS and WCCP work as follows,

the idea is that we should configure WCCP on the router and the WAAS appliance first take care of that analisys before addressing the traffic from your clients.

things to keep in mind when configuring WCCP:

- will the WAAS device be L2 connected to the Router or there will be devices in between the two of them? ( L3 connected)  this is very important to understand what type of WCCP design works the best on your network.

for example if I had a swith directly connected to my WAAS box I will definelty use WCCP L2 redirection which incurs in less CPU utilization.

if I had a Router directly connected to the WAAS box I will be probably force to use WCCP software redirection which is more CPU utilization.

please review the following WCCP and WAAAS design guide:

once WCCP desing has been address, we can start thinking on how the traffic coming from the remote site goes to the data center

based  on a simple  design where you have a Remote WAAS box at the  remote location and you  also  have a Core WAAS appliance at the Data  Center it goes like this:

remote clients > Remote Router>     cloud     < Core Router <   Core Servers

                            WAAS                                   WAAS

1- it does not matter if you have WCCP and an inline mode on each site of your network, you can use either one or even PBR but I see it more difficult to manage  than WCCP or inline mode.

2- there is what we called " WAAS 3 way handshake"  basically what it means is that WAAS needs to know that there is another WAAS appliance at the other site of the network and vicersa.

3- how does the WAAS handshake works, that is where your traffic comes into play


remote client is trying to access his email, let's suppose that all your email exchange servers are at the Data Center on the other site of the client's network.

so that initial request comes from the remote client to Remote Router, WCCP will redirect the traffic coming from the "LAN" interface to the WAAS remote appliance , WAAS will just add a "Hello field" to the client email request.

then WCCP/WAAS remote appliance will just return the traffic back to the router and  the router send it out to his "WAN" interface


once the packet cross the cloud and gets to the Data Center the same way the Core Router will redirect the remote client request to the WAAS appliance ( as I said either inline or WCCP) and then WAAS will know that there is another  WAAS appliance at the other site.

at the core site is the same way WAAS will return the traffic back to the router and then the final destination the email server.

once the traffic comes back it should follow the same path ( no asynchronous paths!!!) and that is how WAAS starts adding optimization to your traffic.

this is explain on my own words and I hope I can address some of your doubst let me know if you have any specific questions.

good luck!

Cisco Employee

waas appliance and manager setup

in addition to my previous post. feel free to provide your design network( if you don't have one  a word description should be enough) and the WAAS/Router hardware and software version.



Community Member

waas appliance and manager setup

Hi there

the setup is exactly as you said, however we are using ip wccp redirect in command, so i guess this is layer 3 setup.

My question to you is, when you say it follows the same path, do you mean every ip packet has this "hello" in it, or does it just do that for the first time a new protocol etc passes through it ?

so how does the traffic flow once it knows there are 2 WAAS devices each side? all traffic must pass through the WAAS or ?


Cisco Employee

waas appliance and manager setup


so there are two processes in here, the one that explain already which is how WAAS discovery itself (  "hello packets and "here I am" response ) and now I need to mention the  WAAS "tcp options" which is basically telling what type of acceleration is being apply to the traffic, this needs to happen to every new connection for WAAS to be able to apply optimization to the traffic.

in the case of asymmetric routing or firewalls in between blocking  WAAS tcp options  there will be issues with WAAS not doing any optimization, but the traffic will still be routed to the client and the server, remember that WAAS redirection methods are transparent to the applications and traffic.

here are some posts that talk about the WAAS initial handshake, firewalls and TCP options in a more formal way.


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